Beneficial arthropods: entomophages and pollinators

Pollination

Main page: Pollination and fertilization

Pollination is one of the key ecosystem services ensuring plant reproduction and crop yield. The vast majority of higher flowering plants depend to some degree on animal pollinators, and among them insects occupy first place (Zakhvatkin, 2001). Entomophilous pollination is especially important for fruit, vegetable, oilseed and legume crops and a number of industrial crops. According to estimates, the contribution of entomophilous pollination to global food production amounts to 235–577 billion USD annually (Borghi et al., 2025).

Many crops not only benefit from pollination but require it for normal fruiting. These include fruits, vegetables, nuts, legumes, as well as stimulant crops such as cocoa and coffee. Among them there are self-incompatible species, plants with morphological prezygotic barriers preventing self-pollination, and seed-propagated crops (Borghi et al., 2025). Pollination by insects affects not only the quantity but also the quality of the harvest: it promotes synchronous ripening of fruits, formation of fruits uniform in shape and size, which are more valued by consumers (Borghi et al., 2025).

The role of pollinators is especially evident in seed production. For example, in the production of seeds of Apiaceae, including carrot, celery, fennel, parsnip and coriander, pollination is carried out by insects; among the most important pollinators are bees, hoverflies, calliphorids, muscids and nectar beetles. For hybrid seed plantings, increased hive placement rates are recommended — up to 5–10 hives per hectare (Geoffriau and Simon, 2021). In open-field and protected vegetable growing, honey bees and bumblebees are also widely used. For cucurbit crops such as cucumber, pumpkin, watermelon and melon, insect pollination is obligatory; it is recommended to place 1–2 colonies per acre, and to obtain a marketable fruit at least eight visits to a female flower are required (Kemble et al., 2022).

However, pollination deficits are increasingly observed in modern agrocenoses. They are characteristic of almond, apple, blueberry, cherry, watermelon and other crops, especially when grown in large monoculture blocks (Borghi et al., 2025). To compensate for the deficit, farmers increasingly use commercial hives of honey bees and bumblebees. In some crops, for example almond, this practice has become necessary for decades (Borghi et al., 2025). Nevertheless, even with hives present, pollination may be insufficient if flowers are unattractive to pollinators or poor in nectar and pollen.

From the standpoint of systematics, it is important to distinguish groups of pollinators not only by taxonomic position but also by functional traits: proboscis length, ability for vibratory pollen collection, temperature tolerance, behavioral plasticity. For example, bumblebees are active at lower temperatures than honey bees and can pollinate crops in unfavorable weather (Kemble et al., 2022). Solitary bees are often more effective for certain flowers than honey bees, but their abundance is harder to maintain over large areas. Therefore, choosing a pollinator is not only a taxonomic but also an agronomic task.

Biological pest control

Biological control is the second most important ecosystem service associated with beneficial arthropods. It is realized through the activity of predators and parasitoids that reduce the abundance of phytophages and thereby reduce crop losses. Unlike parasites, a parasitoid necessarily kills the host during development; predators consume several prey over their lifetime (Van Emden, 2013; McGavin and Davranoglou, 2022). In agrocenoses, both specialized and generalized entomophages occur. The former are confined to a narrow range of hosts; the latter feed on a wide spectrum of prey and can persist in the absence of the main crop.

Among parasitoids, Hymenoptera play a leading role. The families Ichneumonidae and Braconidae include thousands of species parasitizing caterpillars of butterflies, larvae of sawflies, beetles, Diptera and other insects (Van Emden, 2013; McGavin and Davranoglou, 2022). The superfamily Chalcidoidea unites small parasitoids, among which Trichogrammatidae are especially known — egg parasitoids; Aphelinidae — parasitoids of whiteflies and scale insects; Encyrtidae — parasitoids of mealybugs and scale insects; Eulophidae — parasitoids of leaf-mining flies and gall-formers (Van Emden, 2013). In protected ground, Trichogramma, Aphelinus, Encarsia, Eretmocerus, Habrobracon and other species are widely used (Akhatov et al., 2013; Vallad et al., 2018).

Predatory arthropods are represented not only by insects but also by mites, spiders and other arachnids. In greenhouses and gardens, Phytoseiulus and Neoseiulus are used en masse to control spider mites and thrips; Macrolophus — to control whiteflies, aphids and thrips; Orius — to control thrips; Aphidius and Aphidoletes — to control aphids (Akhatov et al., 2013; Vallad et al., 2018). In open ground, ladybirds, ground beetles, rove beetles, green lacewings, hemerobiids, hoverflies, predatory bugs and spiders play an important role (Van Emden, 2013; Albajes and Madeira, 2019).

The economic importance of biocontrol is well illustrated by estimates of pest losses. On average, potential crop losses from animal pests are about 18%, actual losses about 11%, and protection efficiency about 39% (Albajes and Madeira, 2019). At the same time, excessive use of pesticides leads to resistance development, destruction of natural enemies and secondary pest outbreaks. Biological control makes it possible to reduce pesticide load, preserve beneficial fauna and make plant protection more sustainable (Albajes and Madeira, 2019).

Decomposition of organic matter

The third group of ecosystem services is associated with the decomposition of organic matter. In agrocenoses, plant residues, root exudates, animal corpses and excrement accumulate. Their processing is ensured by saprophages, necrophages and coprophages, among which arthropods constitute a significant share. Soil insects and mites accelerate the biogenic cycle of substances, decompose persistent organic compounds and increase soil fertility (Zakhvatkin, 2001).

Classic examples are dung beetles (Scarabaeidae, Geotrupidae) and burying beetles (Silphidae). Dung beetles utilize the excrement of large mammals, bury it in the soil and thereby return nutrients to the soil layer; the introduction of European and African dung beetles into Australia solved the problem of manure accumulation and reduced fly numbers (Van Emden, 2013). Burying beetles, in turn, use the corpses of small animals as a food resource for larvae, accelerating their decomposition and preventing the development of pathogens (Van Emden, 2013).

The soil also contains numerous springtails, mites, larvae of Diptera and beetles that feed on plant residues and fungal mycelium. Their activity improves soil structure, increases its biological activity and promotes mineralization of organic matter (Zakhvatkin, 2001; Ghersa and Martinez-Ghersa, 2019). In agroecosystems with a high proportion of perennial grasses, cover crops and organic fertilizers, the abundance and diversity of soil saprophages increase, which positively affects soil fertility and sustainability.

General characteristics

Ichneumonidae is one of the largest families of Hymenoptera, numbering, according to various estimates, from 60,000 to 100,000 species (McGavin and Davranoglou, 2022). They are predominantly parasitoids of larvae and pupae of other insects, primarily Lepidoptera, sawflies, beetles and Diptera. Adult ichneumonids feed on nectar, honeydew and other sugary secretions, while larvae develop at the expense of the host (Van Emden, 2013).

Morphologically, ichneumonids are characterized by an elongated body, long filiform antennae often exceeding body length, and a well-developed ovipositor, which in some species can be very long. For example, in Rhyssa persuasoria, a parasitoid of horntail larvae, the ovipositor reaches a length comparable to body length and is used to drill wood to a depth of several centimeters (Van Emden, 2013). The wings of ichneumonids have characteristic venation: the presence of the second transverse mediocubital vein (2m-cu) on the forewing and the position of the radial-medial vein (r-m) on the hindwing are diagnostic characters of the family (Van Emden, 2013).

Ichneumonids are distributed worldwide but reach greatest diversity in the tropics and temperate latitudes. In agrocenoses they play an important role as natural regulators of the abundance of butterfly caterpillars, sawfly larvae and other phytophages. However, their effectiveness is often limited by narrow specificity and dependence on the presence of alternative hosts and nectar sources (Albajes and Madeira, 2019).

Biology and ecology

The life cycle of ichneumonids includes egg, larva, pupa and adult stages. The female lays eggs in the host body or on its surface, depending on species and parasitism strategy. Ichneumonid larvae are usually endoparasitoids (developing inside the host body) or ectoparasitoids (developing on the host body surface, often under its integument). Some species are hyperparasitoids, that is, they parasitize other parasitoids (Van Emden, 2013; McGavin and Davranoglou, 2022).

An important feature of many ichneumonids is the presence of polydnaviruses (PDV) — symbiotic viruses integrated into the parasitoid genome. These viruses are injected by the female along with the egg into the host body and suppress its immune response, ensuring successful development of the parasitoid larva. Each ichneumonid species has its own unique type of PDV, making this system one of the most studied examples of parasitoid-host coevolution (McGavin and Davranoglou, 2022).

Ichneumonids demonstrate diverse host-searching strategies. Some species use olfactory signals emanating from damaged plants or the hosts themselves; others orient to vibrations, sounds or visual cues. For example, females of Rhyssa persuasoria place their antennae against tree bark and detect vibrations created by horntail larvae, after which they drill through with the ovipositor and lay an egg directly on the host (Van Emden, 2013). Such precision of searching makes ichneumonids effective biocontrol agents but at the same time limits their use in mass rearing.

Use in biocontrol

Ichneumonids are rarely used in mass-rearing programs because they are difficult to culture under laboratory conditions and production costs are high. However, they play an important role in maintaining natural regulation of pest abundance in agrocenoses. For example, in forest ecosystems ichneumonids control the abundance of sawflies and other phytophages; in orchards, caterpillars of codling moths and leafrollers (Van Emden, 2013; Albajes and Madeira, 2019).

To increase the effectiveness of ichneumonids in agrocenoses, it is recommended to create conditions for their conservation: sow nectar-bearing plants, maintain vegetation diversity, and avoid widespread use of nonselective insecticides. In integrated plant protection, ichneumonids are considered an important component of conservation biocontrol (Albajes and Madeira, 2019).

General characteristics

Braconidae is the second largest family of parasitoid Hymenoptera, numbering about 40,000 described species (McGavin and Davranoglou, 2022). Braconids are close to ichneumonids but differ from them in wing venation: braconids lack the second transverse mediocubital vein (2m-cu) on the forewing, and the radial-medial vein (r-m) on the hindwing is located no farther than half the wing length (Van Emden, 2013). Braconid sizes vary from 1 to 15 mm; most species are smaller than ichneumonids.

Braconids parasitize a wide range of hosts: Lepidoptera, beetles, Diptera, Hymenoptera, Hemiptera and even spiders. Some species are specialized on certain host families or genera; others are polyphages. Braconids play an especially important role in regulating the abundance of aphids, butterfly caterpillars and Diptera larvae (Van Emden, 2013; Akhatov et al., 2013).

Most important genera and species

One of the best-known genera of braconids is Cotesia. Cotesia glomerata parasitizes caterpillars of cabbage whites (Pieris spp.) and can lay up to 100 eggs in one caterpillar; the emerging larvae pupate in yellow silky cocoons on the host body (Van Emden, 2013). Cotesia plutellae is an important biocontrol agent of diamondback moth (Plutella xylostella), one of the most dangerous pests of crucifers (Abrol, 2009; Van Emden, 2013).

The genus Aphidius includes specialized aphid parasitoids. Aphidius colemani is a polyphage used to control melon aphid, green peach aphid and other aphids in greenhouses; Aphidius ervi is a parasitoid of potato aphid and other large aphids (Akhatov et al., 2013; Van Emden, 2013). Females of Aphidius lay eggs in the aphid body; the larva develops inside the host and then pupates, forming a characteristic “mummy” — a swollen aphid body with the parasitoid pupa inside. The appearance of mummies is a visual sign of successful parasitism (Akhatov et al., 2013).

Another important genus is Praon. Unlike Aphidius, Praon larvae leave the aphid body before pupation and form a cocoon under the mummy, often attaching it to a leaf with a silk thread. The mummy remains on top, forming a characteristic “tent” (Akhatov et al., 2013; Van Emden, 2013). Praon volucre is one of the most widespread aphid parasitoids in Europe.

Braconids also include parasitoids of beetle larvae, sawflies and other insects. Some species are used for biocontrol of seed beetles, weevils and leaf-eating beetles. In general, braconids are considered one of the most promising groups for biological pest control due to their high specificity, ability to reproduce rapidly and relatively low cost of mass rearing (Van Emden, 2013; Albajes and Madeira, 2019).

Biology and ecology

The life cycles of braconids are similar to those of ichneumonids. Most species are koinobionts, that is, they allow the host to continue development after infection; the parasitoid larva develops inside the host body, gradually consuming its tissues. Some species are idiobionts, paralyzing or killing the host immediately after infection (McGavin and Davranoglou, 2022).

Braconids parasitizing aphids often possess symbiotic viruses that suppress the host immune response, similar to ichneumonid polydnaviruses. However, the mechanisms of action of these viruses in braconids are less studied. It is also known that some braconids can regulate host behavior: for example, infected caterpillars may leave the host plant and pupate in protected places, which increases parasitoid survival (Van Emden, 2013).

Use in biocontrol

Braconids are widely used in biological control programs both in open ground and in greenhouses. The best-known examples: Aphidius colemani and Aphidius ervi for aphid control; Cotesia plutellae for diamondback moth control; Cotesia glomerata for cabbage white control; Praon volucre as an additional agent against aphids (Akhatov et al., 2013; Van Emden, 2013; Abrol, 2009).

Braconids are usually released as mummies or adults. Mummies are glued to cards or placed in containers that are hung in the greenhouse or field. Adult parasitoids actively search for hosts and lay eggs. The effectiveness of releases depends on temperature, humidity, nectar availability and host density. Under favorable conditions, braconids can completely suppress an aphid population in 30–40 days (Akhatov et al., 2013).

A limitation to the use of braconids is their sensitivity to insecticides. Many neonicotinoids, pyrethroids and organophosphates are highly toxic to parasitoids. Therefore, in integrated plant protection, braconids are used in combination with selective preparations and biological methods (Albajes and Madeira, 2019; Akhatov et al., 2013).

General characteristics

Chalcidoidea is a huge superfamily of parasitoid Hymenoptera, including, according to various estimates, from 22,000 to 500,000 species (McGavin and Davranoglou, 2022). Chalcidoids are predominantly small or very small insects, from 0.2 to 10 mm in length. Many species have bright metallic coloration — green, blue, bronze. Wings usually have reduced venation, often without closed cells; the forewing may have only one anterior vein leading to the pterostigma (Van Emden, 2013).

Chalcidoids parasitize eggs, larvae and pupae of insects from many orders, as well as mites and spiders. Some species are hyperparasitoids. A number of chalcidoids are phytophages forming galls or feeding on seeds. In agrocenoses, chalcidoids play a key role in regulating pest abundance, especially in greenhouses (Van Emden, 2013; Akhatov et al., 2013).

Trichogrammatidae

Trichogrammatidae is a family of the smallest chalcidoids, 0.2–1.5 mm in length. They are egg parasitoids that infect eggs of butterflies, beetles, bugs, thrips, Diptera and other insects. Trichogrammatids are among the most widely used biocontrol agents in the world. Their mass rearing is established on eggs of the Mediterranean flour moth (Ephestia kuehniella), which are sold as cards with parasitized eggs (Van Emden, 2013).

The best-known genus is Trichogramma. Different species of Trichogramma are specialized on different hosts: T. evanescens is a polyphage used against many Lepidoptera; T. brassicae against cabbage moth and other crucifer pests; T. pintoi against European corn borer; T. dendrolimi against pine silkworm (Van Emden, 2013; Akhatov et al., 2013). Trichogramma is released in fields and greenhouses as cards with eggs from which adult parasitoids emerge. Females lay eggs in host eggs; the larva develops inside the egg, killing the embryo. Adults feed on nectar and honeydew.

Trichogramma is effective against egg-laying pests but does not act on larvae and adults. Therefore, its use is most effective in combination with other biocontrol agents, for example braconids or predators (Van Emden, 2013; Akhatov et al., 2013).

Aphelinidae

Aphelinidae is a family of small chalcidoids parasitizing whiteflies, scale insects, aphids, mealybugs and other Sternorrhyncha. Aphelinids demonstrate unique biology: in some species males develop as hyperparasitoids on larvae of their own species, while females develop as primary parasitoids of the host (Van Emden, 2013). This phenomenon is known as “aphelinid biology” and is of interest for understanding the evolution of parasitism.

The best-known species is Encarsia formosa, a parasitoid of greenhouse whitefly (Trialeurodes vaporariorum). Females lay eggs in whitefly larvae of the 2nd–3rd instar; development of the parasitoid is completed inside the nymph, which turns black — a characteristic sign of parasitism. Encarsia formosa is used in greenhouses worldwide to control whitefly on cucumber, tomato, eggplant and ornamental crops (Van Emden, 2013; Akhatov et al., 2013). The effectiveness of Encarsia depends on temperature: at 25–30 °C development is completed in 10–12 days; at 12–14 °C it is much slower. Therefore, in winter, Encarsia releases are less effective.

Another important species is Eretmocerus eremicus, a parasitoid of tobacco whitefly (Bemisia tabaci) and greenhouse whitefly. Eretmocerus is more resistant to high temperatures and low humidity than Encarsia and is used in southern regions and in greenhouses with hot climates (Akhatov et al., 2013; Vallad et al., 2018).

Aphelinus mali is a parasitoid of woolly apple aphid (Eriosoma lanigerum), a dangerous pest of apple. The introduction of A. mali into Europe and North America significantly reduced losses from this pest. The species is used in biocontrol programs in orchards (Van Emden, 2013).

Encyrtidae

Encyrtidae is a large family of chalcidoids parasitizing mealybugs, scale insects, whiteflies, aphids, mites and other arthropods. Encyrtids are characterized by a spur on the middle tibia and often bright metallic coloration. Many species are used in biocontrol (Van Emden, 2013).

The best-known example is Anagyrus lopezi, a parasitoid of the cassava mealybug (Phenacoccus manihoti). The introduction of A. lopezi from South America to Africa in the 1980s completely suppressed populations of this dangerous cassava pest over vast territories (Van Emden, 2013). This is one of the most successful examples of classical biological control.

Other encyrtids are used against scale insects (Comperiella bifasciata), mealybugs (Leptomastix dactylopii), whiteflies (Metaphycus spp.) and other pests. Encyrtidae are an important component of natural regulation of Sternorrhyncha abundance in agrocenoses (Van Emden, 2013; Albajes and Madeira, 2019).

Eulophidae

Eulophidae is a family of small chalcidoids parasitizing leaf-mining flies, gall-formers, psyllids, thrips and other insects. Eulophids are often used to control leaf-mining flies in greenhouses. The best-known genera are Diglyphus, Dacnusa, Opius (Van Emden, 2013; Akhatov et al., 2013).

Diglyphus isaea is a parasitoid of leaf-mining fly larvae, including the tomato leafminer (Liriomyza bryoniae) and other Liriomyza. The female Diglyphus finds a fly larva in the mine, paralyzes it and lays an egg nearby; the parasitoid larva feeds on the paralyzed victim. Diglyphus is also capable of feeding on larval tissues, killing them without laying eggs (Akhatov et al., 2013). Dacnusa sibirica is another important parasitoid of leaf-mining flies, laying eggs inside larvae. Dacnusa is more effective at low temperatures, Diglyphus at high temperatures. Joint use of these two species allows control of leaf-mining flies throughout the season (Akhatov et al., 2013).

Eulophids also include parasitoids of gall-formers, for example Pediobius foveolatus, used against the Mexican bean beetle (Epilachna varivestis) (Van Emden, 2013).

Other families of chalcidoids

Among other chalcidoids important for biocontrol, mention should be made of Pteromalidae, Torymidae, Mymaridae and Trichogrammatidae. Pteromalids parasitize larvae and pupae of Diptera, beetles, butterflies and Hymenoptera; some species are used against flies and pest beetles. Torymids parasitize gall-formers and seed-eaters; mymarids are the smallest chalcidoids, parasitizing eggs of leafhoppers and other insects (Van Emden, 2013).

Parasitism and hyperparasitism

Parasitoids are organisms whose larvae develop at the expense of one host individual, necessarily killing it. Unlike true parasites, parasitoids cannot coexist with the host for a long time; unlike predators, they use only one victim per lifetime (Van Emden, 2013; McGavin and Davranoglou, 2022). Parasitoids can be ectoparasitoids (developing on the host body surface) or endoparasitoids (developing inside the host body). Ectoparasitoids often paralyze the host and feed on its tissues from outside; endoparasitoids lay eggs inside the host body, and larvae develop inside, gradually consuming its tissues (McGavin and Davranoglou, 2022).

Hyperparasitism is a phenomenon in which a parasitoid develops at the expense of another parasitoid. Hyperparasitoids can be obligate or facultative. They play a dual role in agrocenoses: on the one hand, they reduce the abundance of primary parasitoids, weakening biocontrol; on the other hand, they can regulate the abundance of parasitoids themselves, preventing their excessive reproduction. In biocontrol programs, hyperparasitoids are often considered an undesirable factor reducing the effectiveness of releases (Van Emden, 2013; Akhatov et al., 2013).

Specificity of parasitoids

Specificity is one of the key characteristics of parasitoids determining their suitability for biocontrol. Highly specific species infect only one or several closely related host species; polyphages infect a wide range of hosts from different families and orders. Specificity is determined by physiological, behavioral and ecological factors: the female’s ability to find the host, the larva’s ability to overcome the host immune defense, and synchrony of life cycles (McGavin and Davranoglou, 2022; Van Emden, 2013).

For biocontrol, highly specific parasitoids are preferable because they do not destroy nontarget species and do not disturb ecological balance. However, narrow specificity limits the use of a parasitoid only to those agrocenoses where its host is present. Polyphages are more universal but may attack beneficial species, including other entomophages and pollinators. Therefore, choosing a biocontrol agent always requires precise species identification and assessment of its specificity (Albajes and Madeira, 2019; Van Emden, 2013).

Interaction with the host

The interaction between parasitoid and host is a complex coevolutionary process including adaptations on both sides. The host develops protective reactions: immune response, encapsulation, melanization, behavioral avoidance reactions. The parasitoid, in turn, develops mechanisms to overcome defense: injection of symbiotic viruses (polydnaviruses), suppression of the immune response, manipulation of host behavior (McGavin and Davranoglou, 2022).

For example, in many braconids and ichneumonids, the female injects polydnaviruses into the host body along with the egg, which suppress the cellular immune response and prevent encapsulation of the parasitoid larva. In some parasitoid species, the larva secretes factors that suppress melanin synthesis, preventing melanization and death of the parasitoid (McGavin and Davranoglou, 2022). The host, in turn, can develop resistance to the parasitoid, leading to an “arms race” and the appearance of new strains and races of parasitoids.

Mass rearing

Mass rearing of parasitoids is the basis for their use in biocontrol. For rearing, hosts that are easily cultured under laboratory conditions are needed. For example, Trichogramma is reared on eggs of the Mediterranean flour moth (Ephestia kuehniella); Aphidius on grain aphid (Schizaphis graminum) or black bean aphid (Aphis fabae); Encarsia on greenhouse whitefly (Trialeurodes vaporariorum) (Van Emden, 2013; Akhatov et al., 2013).

The rearing process includes several stages: maintaining the host culture, infecting hosts with parasitoids, collecting and storing biomaterial. For storage, diapausing stages are often used (for example, Trichogramma pupae), which can be stored at low temperatures for several months. This allows biomaterial to be accumulated and used as needed (Van Emden, 2013).

The quality of biomaterial is a critical factor in biocontrol success. Parasitoids reared in the laboratory for many generations may lose the ability to search for hosts, reduce fecundity and viability. Therefore, in biocontrol programs regular quality control is carried out: assessment of fecundity, sex ratio, ability to search for and infect hosts (Van Emden, 2013; Albajes and Madeira, 2019).

Introduction (classical biocontrol)

Classical biocontrol is the introduction of exotic parasitoids to control invasive pests. This method involves searching for natural enemies of the pest in its homeland, quarantining and evaluating them, and releasing them in a new region. Successful examples include the introduction of Rodolia cardinalis to control the Australian cottony cushion scale in California; Anagyrus lopezi to control the cassava mealybug; Encarsia formosa to control greenhouse whitefly in Europe (Van Emden, 2013; McGavin and Davranoglou, 2022).

Classical biocontrol requires careful risk assessment: an introduced parasitoid may attack nontarget species, compete with local entomophages or spread beyond the agrocenosis. Therefore, before release, laboratory and field tests are conducted to assess specificity, effectiveness and potential risks (Albajes and Madeira, 2019; Van Emden, 2013).

Seasonal colonization (augmentative biocontrol)

Seasonal colonization is the release of parasitoids into an agrocenosis for rapid suppression of a pest. This method is used when natural parasitoid populations are absent or insufficient to control the pest. Releases can be inoculative (a small number of individuals to establish a population) or inundative (mass release for immediate pest suppression) (Van Emden, 2013).

For example, in greenhouses Encarsia formosa is released prophylactically (5,000 individuals per 1 ha every 10 days) or into whitefly foci (100,000 individuals per 1 ha) (Akhatov et al., 2013). Aphidius colemani is released against aphids at a rate of 5,000–10,000 individuals per 1 ha at weekly intervals (Akhatov et al., 2013). Trichogramma is released in fields as cards with eggs; the release rate depends on the crop and pest density (Van Emden, 2013).

Monitoring effectiveness

Monitoring the effectiveness of releases is an obligatory element of biocontrol programs. It includes assessing pest abundance before and after release, assessing the level of parasitism (share of infected hosts), and assessing parasitoid survival and spread. For monitoring, visual observations, pheromone traps, yellow sticky traps and molecular methods (PCR, sequencing) for species identification are used (Albajes and Madeira, 2019; McGavin and Davranoglou, 2022).

Biology and social organization

The honey bee Apis mellifera is the best-known and most widely used pollinator in the world. It is a social insect living in colonies that can number from 20,000 to 80,000 individuals (Van Emden, 2013). The colony includes one queen (fertile female), several hundred drones (males) and tens of thousands of worker bees (sterile females). Worker bees perform all functions of nest care, foraging and colony defense. The queen lays eggs, from which workers, drones or new queens develop depending on the type of cell and larval nutrition.

A honey bee colony is a single “superorganism” capable of complex communication. One of the best-known communication mechanisms is the “dance” — a system of signals by which scout bees inform other workers of the direction and distance to a food source (Van Emden, 2013). The round dance means that food is nearby (up to 100 m); the waggle dance indicates direction and distance, with the angle of the dance relative to the vertical corresponding to the angle between the direction to the sun and the direction to the food. Such a system allows the colony to quickly mobilize a large number of foragers to a promising area.

Collection of pollen and nectar

Honey bees collect nectar and pollen. Nectar accumulates in the honey stomach and is then processed into honey, which serves as a reserve carbohydrate food. Pollen is collected on the body, combed off with special brushes on the legs and packed into corbiculae — “baskets” on the hind tibiae. A bee can carry up to 20–40 mg of pollen per flight (Van Emden, 2013). When collecting pollen, bees often contact stigmas and stamens, providing cross-pollination. However, when collecting only nectar, bees may avoid contact with anthers, so pollination efficiency depends on the ratio of pollen and nectar collection. Beekeepers use techniques stimulating pollen collection (for example, installing pollen traps) to increase pollination activity.

Use in agriculture

Honey bees are universal pollinators used on hundreds of crops: fruit (apple, pear, cherry, plum, almond), berry (blueberry, cranberry, strawberry), vegetable (cucumber, pumpkin, watermelon, melon, pepper, tomato), oilseed (rapeseed, sunflower, mustard), legume (alfalfa, clover, pea) and many others. For effective pollination, hives must be placed near fields or in greenhouses. Placement rates depend on the crop, flowering density and colony strength.

For example, for cucurbit crops 1–2 colonies per acre (2.5–5 colonies per hectare) are recommended, with each colony containing 40,000–50,000 bees; to obtain a marketable fruit at least 8 visits to a female flower are required (Kemble et al., 2022). For seed plantings of rapeseed and mustard, 3–5 colonies per hectare are recommended (Abrol, 2009). In tomato greenhouses, honey bees are less effective than bumblebees due to flower structure and behavior, so bumblebees are preferred there.

Honey bees are active at temperatures above 12–14 °C, but the most intensive flight is observed at 20–30 °C. They work poorly in windy, rainy and cold weather, so in regions with a cool climate or in early spring their effectiveness may be limited. In such cases, bumblebees and solitary bees come to the rescue.

Biology and social organization

Bumblebees are social bees, but their colonies are significantly smaller than those of honey bees: usually 200–300 workers, rarely up to 500 (Van Emden, 2013; McGavin and Davranoglou, 2022). The colony is founded by an overwintered queen, which in spring builds a nest in soil, under plant residues or in abandoned rodent burrows. Bumblebees do not store large amounts of honey, so their colonies exist for only one season; by autumn new queens and males appear, they mate, after which males and workers die, and queens go to overwinter.

Bumblebees have several advantages over honey bees. They are larger, covered with denser hairs and able to fly at lower temperatures (from 5–10 °C), as well as in windy and cloudy weather. They have a longer proboscis, allowing pollination of flowers with deep corollas (for example, clover, alfalfa, tomato). In addition, bumblebees are capable of vibratory pollen collection (buzz pollination, or sonication): they contract thoracic muscles, causing vibration that shakes pollen out of poricidal anthers (for example, in tomato, eggplant, blueberry, cranberry). This makes them indispensable for pollinating greenhouse tomatoes and a number of other crops.

Use in agriculture

Bumblebees are widely used in greenhouses and open ground. The most frequently used species is Bombus terrestris, which is commercially reared and sold as colonies in special hives. For pollinating tomatoes in greenhouses, one colony per 1,000–2,000 m² is sufficient; for blueberry, cranberry, clover, 2–4 colonies per hectare are recommended (Kemble et al., 2022; Van Emden, 2013). Bumblebees are also effective for pollinating pepper, eggplant, strawberry, raspberry, apple, pear, cherry, alfalfa and many other crops.

Unlike honey bees, bumblebees are not afraid to fly in greenhouses and do not orient by the sun, so they can be used in protected ground year-round. They are also less aggressive and do not sting unless necessary. However, bumblebees are sensitive to insecticides, especially neonicotinoids, which can cause death of workers and disruption of colony development. Therefore, in greenhouses with bumblebees, only selective preparations compatible with pollinators should be used (Vallad et al., 2018; Akhatov et al., 2013).

Problems and limitations

Commercial rearing of bumblebees has led to the spread of parasites and pathogens that can infect wild bumblebees. For example, Nosema bombi and Crithidia bombi have been found in commercial colonies and can be transmitted to wild species. In addition, the introduction of Bombus terrestris into regions where it is not native can lead to displacement of local bumblebee species and disruption of ecological balance. Therefore, when using bumblebees, it is recommended to prefer local species and observe quarantine measures (McGavin and Davranoglou, 2022; Ghersa and Martinez-Ghersa, 2019).

Diversity and biology

Solitary bees constitute the majority of bee species (more than 90%). They do not form colonies, although some species may nest in groups (aggregations). Each female builds her own nest, stores pollen and nectar in it, lays an egg and leaves the offspring without further care. Nests are made in soil (Andrenidae, Halictidae, Colletidae), in stem and wood cavities (Megachilidae, some Apidae), in mollusk shells, in ready-made insect burrows and other shelters (McGavin and Davranoglou, 2022; Van Emden, 2013).

The sizes of solitary bees vary from 2 to 30 mm. Many species have bright coloration resembling wasps or bumblebees. Adults feed on nectar and pollen; larvae develop on reserves left by the female. Adult lifespan is from several weeks to several months; usually larvae or pupae overwinter, less often adults.

Most important families and their role in pollination

Andrenidae — a large family of solitary soil-nesting bees. Andrena spp. are active in early spring and pollinate fruit trees (apple, pear, cherry, plum), berry crops, alfalfa, clover. They are important pollinators in regions with cool climates because they emerge earlier than honey bees (Van Emden, 2013).

Halictidae — bees often called sweat bees. They can be solitary or social (primitive eusociality). Halictus and Lasioglossum are common genera pollinating many vegetable, fruit and forage crops. Some species are used for pollinating alfalfa and clover (McGavin and Davranoglou, 2022).

Megachilidae — include leafcutter bees (Megachile) and mason bees (Osmia). Megachile rotundata (alfalfa leafcutter bee) is one of the most important managed pollinators of alfalfa in North America and Europe. Osmia cornuta and Osmia lignaria (mason bee) are used for pollinating apple, pear, cherry, almond. They are more effective than honey bees at low temperatures and in rainy weather (Van Emden, 2013; McGavin and Davranoglou, 2022). Megachile builds nests from cut pieces of leaves; Osmia uses mud or clay for partitions.

Colletidae — primitive solitary bees nesting in soil or stems. They secrete a film from the mouth with which they line cells. They occur on many flowers but are less often used in managed pollination.

Apidae — besides honey bees and bumblebees, include solitary bees such as carpenter bees (Xylocopa), small carpenter bees (Ceratina), and cleptoparasites (Nomada). Xylocopa spp. pollinate many tropical and subtropical crops, including eggplant, tomato, pepper, passionflower.

Advantages and limitations of use

Solitary bees have several advantages: they are often more effective than honey bees for specific crops; they do not require complex care; they are less susceptible to mass diseases; they can work at low temperatures. However, their abundance is difficult to control, and mass rearing is limited to a few species (Megachile rotundata, Osmia spp., Nomia melanderi). In addition, solitary bees are sensitive to pesticides and need suitable nesting substrates and forage plants. To support them, it is recommended to create “bee hotels” (nesting houses), preserve areas with open soil, and sow nectar-bearing plants (Ghersa and Martinez-Ghersa, 2019; Abrol, 2009).

Crops dependent on pollination

Many agricultural crops depend on insect pollinators for yield formation. These include fruit crops (apple, pear, cherry, plum, peach, apricot, almond), berry crops (blueberry, cranberry, strawberry, raspberry, blackberry, currant), vegetables (cucumber, pumpkin, watermelon, melon, pepper, tomato, eggplant), oilseeds (rapeseed, sunflower, mustard, flax), legumes (alfalfa, clover, pea, bean), as well as some industrial crops (coffee, cocoa, tea). The vast majority of these crops require cross-pollination, and insects provide pollen transfer between flowers (Borghi et al., 2025; Klein et al., 2007).

Economic importance

The contribution of entomophilous pollination to global food production is estimated at 235–577 billion USD annually (Borghi et al., 2025). For individual crops, the share of pollination in yield formation can be very high. For example, for blueberry, 65–75% of variation in fruit set, size and mass of berries, as well as ripening synchrony, is due to pollination (Borghi et al., 2025). For almond, apple, cherry and watermelon, crop losses with insufficient pollinators can reach 50% or more. In vegetable seed production (carrot, onion, cabbage, radish), insect pollination is critically important for obtaining seeds (Geoffriau and Simon, 2021; Abrol, 2009).

Examples of yield increase

Numerous studies show that pollination by bees and bumblebees increases yield and product quality. For example, in experiments with rapeseed (Brassica napus), the presence of bees increased the number of pods per plant by 53%, pod length by 6%, number of seeds per pod by 13%, and total seed yield by more than two times (Abrol, 2009). For mustard (Brassica juncea), pollination by Apis cerana increased pod set by 239% compared with isolation from insects and by 2.65% compared with open pollination; oil content in seeds increased by 21.3% (Abrol, 2009). For white mustard (Sinapis alba), the presence of bees doubled the number of seeds per pod and increased pod set by 50% (Abrol, 2009).

In fruit growing, pollination by bumblebees and solitary bees produces larger, more uniform fruits with better taste. For example, in apple orchards the use of Osmia cornuta increases fruit set and reduces the share of deformed fruits. In greenhouse tomato production, bumblebees provide vibratory pollination, without which fruit set is extremely low (Vallad et al., 2018; Akhatov et al., 2013).

Colony collapse disorder

Colony collapse disorder (CCD) is a syndrome in which worker bees leave the hive and do not return, leaving the queen and brood. The causes of CCD are not fully understood, but a complex effect of several factors is assumed: parasites (especially the mite Varroa destructor), viral infections (deformed wing virus, acute bee paralysis virus), pesticides, lack of food, stress from transportation and monoculture nutrition (Van Emden, 2013; McGavin and Davranoglou, 2022). CCD causes enormous economic damage to beekeeping and agriculture because it leads to mass death of colonies and reduced pollination activity.

Pesticides

Pesticides are one of the main threats to pollinators. Insecticides, especially neonicotinoids (imidacloprid, thiamethoxam, clothianidin), pyrethroids and organophosphates, are toxic to bees and bumblebees. They can cause acute death, as well as sublethal effects: impaired orientation, reduced learning ability, worsened memory, reduced fecundity, disrupted thermoregulation and immunity (Vallad et al., 2018; Akhatov et al., 2013). Even low concentrations of neonicotinoids in nectar and pollen can accumulate in the colony and lead to its weakening.

Pesticides applied during crop flowering, when bees actively collect nectar and pollen, are especially dangerous. In such cases, it is recommended either to temporarily remove hives from the field or to apply preparations only in the evening, after bee flight has ended. In greenhouses with bumblebees, only selective insecticides safe for pollinators should be used (Kemble et al., 2022; Abrol, 2009).

Parasites and pathogens

The mite Varroa destructor is the most dangerous parasite of honey bees. It feeds on the hemolymph of adults and larvae, transmits viruses and weakens the colony. Without control, varroosis leads to colony death within 1–3 years (Van Emden, 2013). Other parasites: Nosema apis and N. ceranae (microsporidia causing nosemosis), Acarapis woodi (tracheal mite), as well as various viruses (deformed wing virus, sacbrood virus, chronic bee paralysis virus). Bumblebees are also susceptible to parasites: Nosema bombi, Crithidia bombi, Apicystis bombi. Commercial rearing of bumblebees contributes to the spread of these pathogens into wild populations (McGavin and Davranoglou, 2022).

Habitat and forage base loss

Intensive agriculture leads to a reduction in the diversity of flowering plants and the disappearance of field margin habitats, hedgerows, meadows and wastelands. Monocultures provide pollinators with food only during a short flowering period, while at other times bees experience a shortage of nectar and pollen. In addition, plowing, herbicide use and urbanization destroy nesting substrates for solitary bees and bumblebees (Ghersa and Martinez-Ghersa, 2019; Borghi et al., 2025).

Climate change

Climate change affects pollinators through shifts in plant flowering times, changes in the quantity and quality of nectar and pollen, and direct temperature stresses. Droughts reduce nectar volume and sugar concentration, decrease pollen quantity and its nutritional value (Brunet et al., 2025). This can lead to a mismatch between the period of pollinator activity and the period of crop flowering (phenological mismatch), reducing pollination efficiency. In addition, rising temperatures can contribute to the spread of parasites and pathogens.

Creation of flower strips and hedgerows

Sowing flower strips (wildflower strips) along fields and in gardens is one of the most effective ways to support pollinators. Such strips provide a continuous source of nectar and pollen throughout the season and also serve as shelter for nesting and overwintering. It is recommended to sow mixtures of local plant species flowering at different times: for example, clover, phacelia, mustard, sweet clover, cornflower, chamomile, sunflower. Hedgerows of shrubs and trees also create favorable conditions for pollinators and natural enemies of pests (Ghersa and Martinez-Ghersa, 2019; Abrol, 2009).

Nesting houses and substrates

For solitary bees and bumblebees, artificial nests can be created: “bee hotels” made of drilled wooden blocks, bundles of reeds, ceramic tubes; bumblebee boxes — boxes with dry grass or moss buried in the ground. It is important that nests are protected from rain and wind and located in warm, well-warmed places. For ground-nesting bees, areas with open, untreated soil must be preserved (Van Emden, 2013; McGavin and Davranoglou, 2022).

Reducing pesticide load and choosing selective preparations

In integrated plant protection, priority is given to biological and agrotechnical methods. If pesticides must be used, preparations with low toxicity for pollinators should be chosen, applied in the evening after bee flight has ended, and spraying of flowering crops should be avoided. In greenhouses with bumblebees and predatory mites, only compatible preparations should be used; many neonicotinoids are prohibited for use under such conditions (Vallad et al., 2018; Akhatov et al., 2013; Kemble et al., 2022).

Organic farming and integrated plant protection

Organic farming is generally more favorable for pollinators because it excludes synthetic pesticides and mineral fertilizers and preserves plant diversity and soil fauna. However, problems are also possible in organic farming: for example, the use of sulfur or copper preparations can be toxic to bees. Integrated plant protection (IPM) combines biological, cultural, physical and chemical methods, minimizing impact on beneficial fauna. Key elements of IPM: pest monitoring, economic thresholds, selective insecticides, conservation of natural enemies and pollinators (Albajes and Madeira, 2019).

Citizen science and monitoring

Monitoring the abundance and diversity of pollinators is an important task for assessing the effectiveness of support measures. Citizen science allows volunteers to be involved in collecting data on flower visits, nesting and species distribution. There are international programs such as Global Pollinator Watch, BeeWatch, iNaturalist, which help track the state of pollinator populations. In agrocenoses, it is recommended to conduct regular surveys of fields and gardens, use yellow sticky traps, visual observations, and molecular methods for species identification (McGavin and Davranoglou, 2022; Ghersa and Martinez-Ghersa, 2019).

Breeding pollinator-friendly crops

Modern breeding programs are often oriented toward agronomic traits (yield, disease resistance, transportability) but ignore traits attractive to pollinators: aroma, abundant nectar and pollen, ease of access to reward. As a result, some commercial varieties become unattractive to bees. For sustainable pollination, it is necessary to include selection of genotypes with rich floral rewards and flower morphology convenient for pollinators in breeding programs. This is especially important for crops that strongly depend on insect pollination: blueberry, apple, almond, cucurbits (Borghi et al., 2025).

General characteristics

Chrysopidae is the largest and best-known family of Neuroptera, including about 1,200–2,000 species. Adult green lacewings usually have a green body and transparent wings with green veins; eyes in many species are golden or reddish-golden, which gave the family its name. Body size varies from 5 to 20 mm, wingspan from 15 to 40 mm (Van Emden, 2013; McGavin and Davranoglou, 2022).

Adult green lacewings are predominantly crepuscular or nocturnal and often fly to light. They feed on nectar, pollen and honeydew, but some species (for example, Chrysopa septempunctata, C. perla, C. formosa) remain predators as adults. Larvae of all Chrysopidae species are active predators armed with long sickle-shaped mandibles that form sucking mouthparts: through them the larva injects digestive enzymes into the prey body and sucks out its contents (Van Emden, 2013; McGavin and Davranoglou, 2022).

Biology and life cycle

Female green lacewings lay eggs on long thin stalks attached to leaves or stems. This design protects eggs from predators and reduces the risk of cannibalism among hatched larvae. Larvae emerge from eggs after a few days and immediately begin searching for prey. They pass through three larval instars, after which they pupate in a rounded white silk cocoon, often attached to a leaf or bark. Development duration depends on temperature: at 25 °C the cycle takes about 2–3 weeks; at lower temperatures, longer. In temperate latitudes, many species overwinter as adults or pupae, entering diapause induced by shortening photoperiod (Van Emden, 2013; McGavin and Davranoglou, 2022).

Green lacewing larvae are very voracious. One larva of Chrysoperla carnea destroys from 200 to 500 aphids during development, and larvae of Chrysopa septempunctata up to 500–800 aphids. They also feed on mites, thrips, whiteflies, butterfly eggs, small caterpillars and other soft-bodied insects. Some species are capable of cannibalism, especially when food is scarce. Adult predatory green lacewings also eat aphids, but their contribution to reducing pest abundance is smaller than that of larvae (Van Emden, 2013; Akhatov et al., 2013).

Most important species and their use

Chrysoperla carnea (common green lacewing) is the most widespread and studied species. Adults are green, with a brownish-red stripe on the cheeks and a yellow stripe on the back. Larvae feed on aphids, mites, thrips and insect eggs. This species is used in biocontrol in greenhouses and open ground against aphids, whiteflies, thrips and spider mites. Larvae are released into pest foci at a predator:prey ratio of 1:5–1:20 (Akhatov et al., 2013; Van Emden, 2013).

Chrysoperla sinica (Chinese green lacewing) is a species introduced from tropical regions of China. It differs from C. carnea in the transverse veins at the distal end of the forewing, which are black. It is more thermophilic and hygrophilic than C. carnea, which makes it effective in greenhouse conditions with high temperature and humidity. Larvae consume on average 358 aphids during development. For release, a predator:prey ratio of 1:10–1:20 is recommended (Akhatov et al., 2013).

Chrysopa septempunctata is a large green lacewing; adults and larvae prey. It is used in gardens and fields against aphids, mites and caterpillars. Adults need additional feeding on nectar and pollen, so the presence of flowering plants is important for their conservation (Van Emden, 2013).

Chrysopa perla and C. formosa are also predatory species found in Europe and Asia. They are used in biocontrol programs, but less often than C. carnea and C. sinica, due to difficulties in mass rearing.

Advantages and limitations of using green lacewings

Green lacewings have several advantages as biocontrol agents. They are polyphages, able to feed on different pests, actively search for prey and have high voracity. Larvae are easily reared under laboratory conditions on eggs of the Mediterranean flour moth (Ephestia kuehniella), which allows producing large volumes of biomaterial. Larvae can be released both in greenhouses and in open ground (Akhatov et al., 2013; Van Emden, 2013).

However, there are limitations. Green lacewings are sensitive to insecticides, especially neonicotinoids, pyrethroids and organophosphates. The use of such preparations can destroy both pests and entomophages. In addition, adults need nectar and pollen, so in monoculture agrocenoses without flowering plants their abundance quickly declines. Larvae may suffer from cannibalism at high density, reducing release effectiveness. Finally, the cost of mass rearing green lacewings remains relatively high, limiting their widespread use in open ground (Van Emden, 2013; Albajes and Madeira, 2019).

General characteristics

Hemerobiidae is the second most important family of Neuroptera in the agrosphere. Externally they resemble green lacewings but are usually smaller (wingspan 5–30 mm), have brownish or grayish coloration and are covered with short hairs. Wings have a dense network of veins but lack the characteristic green color of Chrysopidae. Eyes of hemerobiids are dark, without golden sheen (Van Emden, 2013; McGavin and Davranoglou, 2022).

Unlike many green lacewings, in hemerobiids both larvae and adults prey. They feed mainly on aphids, mites, thrips, whiteflies, eggs and small insect larvae. Hemerobiids are more cold-resistant than green lacewings and active at lower temperatures, making them valuable biocontrol agents in early spring and autumn periods (Akhatov et al., 2013; Van Emden, 2013).

Biology and ecology

Female hemerobiids lay eggs on leaves and stems, often along veins. Eggs do not have stalks, as in green lacewings, and are attached to the substrate by a short stalk or directly. Larvae emerge after a few days, actively search for prey and pass through three instars. They pupate in a thin silk cocoon on the plant or in plant residues. Development duration depends on temperature and species: at 20–25 °C the cycle takes 3–4 weeks. Adults or pupae overwinter (Van Emden, 2013; McGavin and Davranoglou, 2022).

Micromus angulatus is one of the best-known hemerobiid species, used in greenhouses against potato aphid and green peach aphid at reduced temperatures. Adults and larvae feed on aphids, as well as pollen and nectar. It develops over a wide temperature range from 15 to 35 °C, optimum 18–22 °C. Fecundity reaches 2,000 eggs. Larval voracity during development is 80–300 aphids. The preimaginal period at 25 °C and relative humidity 70–80% is about 16 days. For release, larvae of the 1st–2nd instar are recommended at a predator:prey ratio of 1:5–1:20 (Akhatov et al., 2013).

Other genera of hemerobiids — Hemerobius, Wesmaelius, Sympherobius — also occur in agrocenoses and participate in reducing the abundance of aphids, mites and other pests. They are especially important in gardens and forest plantations, where they persist on trees and shrubs.

Advantages and limitations of using hemerobiids

Hemerobiids have an advantage over green lacewings under low-temperature conditions: they are active at 10–15 °C, whereas green lacewings are sluggish at such temperatures. This makes them indispensable for biocontrol in early spring, when many pests are already active and specialized predators have not yet reproduced. In addition, hemerobiids are less demanding of humidity and can work effectively in dry conditions (Akhatov et al., 2013; Van Emden, 2013).

Limitations are associated with difficulties in mass rearing. Hemerobiids are more difficult to rear than green lacewings, and their biomaterial is more expensive. They are also sensitive to insecticides, especially pyrethroids and neonicotinoids. In open ground, their abundance strongly depends on the presence of alternative prey and shelters. Therefore, hemerobiids are more often used in conservation biocontrol programs than in mass releases (Albajes and Madeira, 2019; Van Emden, 2013).

Greenhouses

In greenhouses, Neuroptera are used to control aphids, whiteflies, thrips and mites. The most frequently used are Chrysoperla carnea, Chrysoperla sinica, Micromus angulatus. Larvae are released into pest foci, usually at a predator:prey ratio of 1:5–1:20. At high pest density the rate is increased. For prophylaxis, larvae are released over the entire greenhouse area at intervals of 1–2 weeks (Akhatov et al., 2013).

Neuroptera combine well with other entomophages: Phytoseiulus, Neoseiulus, Encarsia, Eretmocerus, Macrolophus. However, it must be taken into account that some predators may eat each other (intraguild predation), so in joint releases it is important to select compatible species and rates. In greenhouses with bumblebees, insecticides toxic to pollinators cannot be used; Neuroptera are also sensitive to such preparations (Vallad et al., 2018; Akhatov et al., 2013).

Gardens and open ground

In gardens, green lacewings and hemerobiids are important natural enemies of aphids, mites, psyllids and caterpillars. They persist on trees and shrubs, as well as on flowering plants between rows. To support their abundance, it is recommended to sow nectar-bearing plants, create hedgerows, and avoid widespread use of nonselective insecticides. In apple orchards, green lacewings can significantly reduce apple aphid numbers, and hemerobiids can reduce spider mites (Van Emden, 2013; Albajes and Madeira, 2019).

In open ground, mass releases of green lacewings are less common due to cost and difficulty of retaining them in the agrocenosis. Conservation methods are more often used: preserving natural populations, creating plant banks, reducing pesticide load. For example, in vegetable rotations with flowering green manures and strips of wild flowers, the abundance of green lacewings and hemerobiids increases, which positively affects pest control (Ghersa and Martinez-Ghersa, 2019).

Compatibility with other protection methods

Neuroptera are compatible with biological methods: releases of Trichogramma, braconids, aphidiids, predatory mites. They are also compatible with agrotechnical practices: crop rotation, cover crops, mulching. However, they are incompatible with widespread use of nonselective insecticides. If chemical treatment is necessary, preparations with low toxicity for entomophages should be chosen, applied in the evening after flight has ended, and spraying of flowering plants should be avoided. In greenhouses with bumblebees and predatory mites, only compatible preparations should be used (Vallad et al., 2018; Kemble et al., 2022).

General characteristics

Phytoseiidae is one of the most important families of predatory mites in agrocenoses. More than 2,500 species have been described in the world fauna, many of which are used in biological control. Phytoseiids are small mites, usually 0.2–0.5 mm in body length. They have an oval or pear-shaped body covered with setae and well-developed chelicerae adapted for grasping and piercing prey (Van Emden, 2013; Akhatov et al., 2013).

Phytoseiids feed on a wide range of small arthropods: spider mites, thrips, whiteflies, gall mites, as well as pollen and nectar. Some species are specialized predators of spider mites (for example, Phytoseiulus persimilis), others are polyphages (for example, Neoseiulus cucumeris, Amblyseius swirskii). The diet spectrum determines their suitability for controlling specific pests and the possibility of persisting in an agrocenosis in the absence of the main prey (Akhatov et al., 2013; Van Emden, 2013).

Most important species and their biology

Phytoseiulus persimilis is a specialized predator of spider mites, primarily Tetranychus urticae and T. cinnabarinus. It was first discovered in Algeria, then introduced into many countries. Adults and nymphs actively search for spider mite colonies and destroy eggs, larvae, nymphs and adults. One female destroys 20–25 prey individuals per day or up to 30 eggs. Development from egg to adult takes 5–7 days at 25–30 °C, which is 1.5–2 times faster than in the prey. This allows the predator to rapidly increase in number and suppress spider mite outbreaks (Akhatov et al., 2013; Van Emden, 2013).

Phytoseiulus is sensitive to low relative humidity: below 60% humidity, survival of eggs and nymphs sharply decreases. Optimal conditions for its use are temperature 25–30 °C and humidity above 70%. It is unable to persist for long in the absence of spider mites, so releases are carried out either prophylactically or into pest foci. The release rate depends on prey density: at a predator:prey ratio of 1:5–1:10 a rapid effect is achieved; at 1:20–1:50, a slower but more stable effect (Akhatov et al., 2013).

Neoseiulus cucumeris (formerly Amblyseius cucumeris) is a polyphage feeding on thrips, spider mites, whiteflies and pollen. It is widely used in greenhouses to control western flower thrips (Frankliniella occidentalis). Optimal conditions: temperature 20–25 °C, humidity 70–90%. Fecundity reaches 40–50 eggs. The predator can persist for a long time in the crop when pollen is available, allowing prophylactic releases. To support the population, it is recommended to sprinkle pollen (for example, alder or birch) on leaves (Akhatov et al., 2013; Vallad et al., 2018).

Neoseiulus californicus is a polyphage resistant to high temperatures and low humidity. It feeds on spider mites, thrips and small insects. It is used in greenhouses and gardens, especially in southern regions. It can persist on plants at low prey density, feeding on pollen and other alternative sources (Akhatov et al., 2013).

Amblyseius swirskii is a polyphage used to control whiteflies, thrips and spider mites. It is resistant to high temperatures and actively reproduces at 25–30 °C. It is widely used in greenhouses on vegetable and ornamental crops (Vallad et al., 2018).

Typhlodromus pyri is a predatory mite used in orchards to control European red mite (Panonychus ulmi). Unlike Phytoseiulus, it can persist for a long time in the orchard, feeding on pollen, fungal mycelium and small insects. It is released at a rate of 25,000 individuals per hectare. It is sensitive to insecticides, so selective preparations must be used in integrated orchards (Van Emden, 2013; Akhatov et al., 2013).

Use in biocontrol

Phytoseiids are used in greenhouses and open ground. In greenhouses, the most common are Phytoseiulus persimilis, Neoseiulus cucumeris, N. californicus, Amblyseius swirskii. Releases are carried out either prophylactically (over the entire area at intervals of 1–2 weeks) or into pest foci (at a predator:prey ratio of 1:5–1:20). To support predators, banker plants (for example, plants with pollen) and pollen supplementation are used (Akhatov et al., 2013; Vallad et al., 2018).

In gardens, phytoseiids persist naturally under low pesticide load. To support Typhlodromus pyri and other species, it is recommended to sow nectar-bearing plants, create hedgerows, and avoid broad-spectrum insecticides. In organic orchards, predatory mites are often the main factor restraining spider mite abundance (Van Emden, 2013; Albajes and Madeira, 2019).

General characteristics

Tetranychidae is a family of phytophages including more than 1,200 species. Spider mites are among the most dangerous pests of crops in greenhouses and open ground. They feed on the contents of plant cells, piercing the epidermis with chelicerae and sucking out sap. As a result, characteristic damage forms: small light spots (stippling), which merge into chlorotic areas; leaves yellow, brown and dry out. At high abundance, mites cover leaves with webbing, which impedes photosynthesis and respiration (Akhatov et al., 2013; Van Emden, 2013).

Spider mites are distinguished by high biotic potential: short life cycle (5–20 days depending on temperature), high fecundity (up to 100–150 eggs per female), ability to rapidly disperse with wind, animals and humans. Many species can enter diapause under unfavorable conditions, allowing them to survive winter cold or summer drought (Akhatov et al., 2013; Van Emden, 2013).

Most important species

Tetranychus urticae (two-spotted spider mite) is a cosmopolitan species damaging more than 200 plant species, including cucumber, tomato, pepper, eggplant, bean, soybean, cotton and many ornamental crops. The female body is oval, 0.4–0.5 mm, yellowish-green with dark spots on the sides. Diapausing females of orange-red color overwinter, hiding in bark cracks, under plant residues, in soil. In spring they emerge, feed and lay eggs. Development from egg to adult at 30 °C takes 7–8 days; at 20 °C, 14–20 days. Optimum temperature is 25–30 °C, humidity 40–60%. At high humidity (above 80%) development slows, and at 100% it stops (Akhatov et al., 2013; Van Emden, 2013).

Tetranychus cinnabarinus (carmine spider mite) is a closely related species, often considered a color form of T. urticae. It differs by constant red coloration and absence of diapause, allowing it to damage crops in greenhouses year-round. It prefers tomatoes but also damages cucumber, pepper, eggplant and ornamental crops. Optimum temperature is 29–33 °C. At 25 °C and humidity 80%, a female lays 100–150 eggs over 20–30 days (Akhatov et al., 2013).

Panonychus ulmi (European red mite) is a dangerous pest of fruit crops, especially apple. The female body is red, with long setae. Eggs overwinter, laid on branch bark. In spring larvae emerge and feed on the underside of leaves. Damage appears as silvering, then bronzing of leaves. At high abundance, mites can completely destroy the leaf apparatus, reducing yield and fruit quality. In orchards P. ulmi is controlled by predatory mites Typhlodromus pyri and other phytoseiids (Van Emden, 2013; Akhatov et al., 2013).

Panonychus citri (citrus red mite) is a pest of citrus crops. It damages leaves, young shoots and fruits. It causes silvering and necrosis of leaves and fruit drop. It is distributed in tropical and subtropical regions (Van Emden, 2013).

Oligonychus spp. — include pests of cereals, cotton, tea and coffee. For example, Oligonychus coffeee damages tea and coffee, and O. pratensis damages maize and sorghum (Van Emden, 2013).

Damage and harmfulness

Spider mites feed on the underside of leaves, where they are less noticeable. The first signs of damage are small light dots (stippling), which appear along veins. As mites multiply, the spots merge, leaves become marbled, then yellow and dry out. In some crops (for example, cucumber), damaged leaves become brittle and covered with webbing, on which mites spread. Crop losses can reach 30–50% or more, especially in greenhouses where mites reproduce year-round (Akhatov et al., 2013; Van Emden, 2013).

In addition to direct damage, spider mites can transmit viral diseases. For example, T. urticae is capable of transmitting tobacco necrosis virus, cucumber mosaic virus and others. This increases the economic damage from mites (Van Emden, 2013).

Laelapidae

Laelapidae is a family of soil predatory mites living in the upper soil layers, in compost, under plant residues. They feed on small invertebrates: nematodes, enchytraeids, Diptera larvae (including sciarids), springtails and mites. The best-known species is Hypoaspis aculeifer (formerly Geolaelaps aculeifer). It is a small mite 0.5–1 mm long, brownish, with well-developed chelicerae. It is used in greenhouses to control soil pests, especially larvae of fungus gnats (Bradysia spp.) and other sciarids (Akhatov et al., 2013; Van Emden, 2013).

Hypoaspis aculeifer is reared under laboratory conditions on nematodes or other small invertebrates. It is released into soil or substrate at a rate of 50–100 individuals per 1 m². It can persist in soil for a long time, feeding on alternative prey. Optimal conditions: temperature 20–25 °C, humidity 70–80%. The mite is sensitive to insecticides used against soil pests, so selective preparations must be chosen when using it (Akhatov et al., 2013).

Macrochelidae

Macrochelidae is another family of soil predatory mites close to Laelapidae. They also live in soil, compost, manure, feeding on small invertebrates, including fly larvae, nematodes and springtails. The best-known species is Macrocheles robustulus, used to control sciarids and other soil pests in greenhouses. Mites of this family are larger than Laelapidae (0.8–1.5 mm), have dark brown coloration and are clearly visible in the substrate. They are reared under laboratory conditions and released into soil or substrate (Van Emden, 2013; Akhatov et al., 2013).

Macrochelidae can play an important role in natural regulation of soil pest abundance. They are resistant to some insecticides but also sensitive to broad-spectrum preparations. In organic farming they are one of the key components of soil biota (Ghersa and Martinez-Ghersa, 2019).

Strategies for using predatory mites

Biocontrol of spider mites in greenhouses is based on the use of predatory mites, primarily Phytoseiulus persimilis and Neoseiulus californicus. The strategy depends on pest density and environmental conditions.

Prophylactic releases. Conducted at low pest density or before its appearance. For example, release of Neoseiulus cucumeris or Amblyseius swirskii over the entire greenhouse area at intervals of 2–4 weeks. These species can feed on pollen, so they persist in the crop even in the absence of spider mites (Akhatov et al., 2013; Vallad et al., 2018).

Release into foci. Conducted when the first foci of spider mites are detected. Phytoseiulus persimilis is released at a predator:prey ratio of 1:5–1:20. The higher the prey density, the more predator is needed. Release is carried out in the morning or evening to avoid overheating. The predator quickly finds mite colonies and destroys them. After 2–3 weeks, spider mite abundance sharply decreases, and then the predator leaves the focus or dies of starvation (Akhatov et al., 2013).

Joint releases. A combination of Phytoseiulus persimilis and Neoseiulus californicus is often used. The former quickly suppresses the outbreak, the latter persists longer and prevents repeated pest reproduction. It can also be combined with releases of green lacewings, hemerobiids, predatory bugs (Macrolophus, Orius) and parasitoids (Encarsia, Eretmocerus) (Akhatov et al., 2013; Vallad et al., 2018).

Monitoring and decision-making

Monitoring of spider mites and their predators is an obligatory condition for successful biocontrol. Visual inspections of leaves (especially the underside), yellow sticky traps, as well as washing or imprint methods are used. The economic threshold of harmfulness (ETH) for spider mites in greenhouses is usually 1–5 individuals per leaf (depending on crop and developmental stage). When the ETH is reached, a decision is made to release predators or apply acaricides (Albajes and Madeira, 2019; Akhatov et al., 2013).

Conditions for effectiveness

The effectiveness of predatory mites depends on temperature, humidity, presence of alternative prey and pollen, and compatibility with other protection methods. Optimal conditions for Phytoseiulus persimilis: 25–30 °C, humidity 70–80%. At low humidity (below 60%) its effectiveness decreases. Neoseiulus californicus is more resistant to dryness and high temperatures, so it is used in hot regions. In greenhouses with bumblebees, it is necessary to avoid insecticides toxic to pollinators and choose preparations compatible with predatory mites (Akhatov et al., 2013; Vallad et al., 2018).

The problem of resistance

Spider mites have a high ability to develop resistance to acaricides. This is due to their short life cycle, high fecundity and genetic variability. As a result, many preparations that were previously effective lose their activity. For example, T. urticae has developed resistance to organophosphates, pyrethroids, avermectins and some neonicotinoids. Therefore, in integrated plant protection it is recommended to alternate preparations with different mechanisms of action and use biological methods (Akhatov et al., 2013; Van Emden, 2013).

Selectivity of preparations

To preserve predatory mites, selective acaricides and insecticides that do not kill entomophages must be chosen. For example, preparations based on avermectins (Fitoverm, Akarin, Vertimek) have relatively low toxicity for phytoseiids but are highly toxic to spider mites. Preparations based on sulfur, soap and oils are also less dangerous for predators. In contrast, pyrethroids, organophosphates and neonicotinoids are often highly toxic to phytoseiids and must be used with caution (Akhatov et al., 2013; Kemble et al., 2022).

In tables of relative toxicity of insecticides for beneficial arthropods (for example, in Kemble et al., 2022) it is indicated that most pyrethroids and neonicotinoids have a high level of impact on predatory mites (H), whereas avermectins, spinetoram, methoxyfenozide have low or medium (L–M). This must be taken into account when planning treatments.

Application strategy

In integrated plant protection, the following strategy is recommended:

1. Prevention. Maintaining a high level of biodiversity, creating conditions for preserving natural populations of predatory mites (flower strips, hedgerows, banker plants).

2. Monitoring. Regular inspection of plants, assessment of pest and predator abundance. Use of ETH for decision-making.

3. Biological control. Release of predatory mites (Phytoseiulus persimilis, Neoseiulus californicus, N. cucumeris, Amblyseius swirskii) in accordance with recommendations.

4. Chemical control (if necessary). Use of selective acaricides only when ETH is exceeded, taking into account compatibility with predators. Alternation of preparations of different classes to prevent resistance.

5. Effectiveness assessment. Constant monitoring after treatments, adjustment of strategy.

Such an approach makes it possible to reduce pesticide load, preserve beneficial fauna and ensure sustainable production (Albajes and Madeira, 2019; Akhatov et al., 2013; Kemble et al., 2022).

Coccinellidae (ladybirds)

Ladybirds are one of the best-known families of predatory beetles. Adults usually have a rounded or oval body, convex elytra with a bright pattern of spots and bands. Ladybird larvae externally resemble small “crocodiles,” often dark gray or black with yellow or orange spots. Both adults and larvae of most species are active predators feeding on aphids, mites, whiteflies, scale insects, mealybugs and other soft-bodied insects (Van Emden, 2013; McGavin and Davranoglou, 2022).

The best-known species: seven-spotted ladybird Coccinella septempunctata, two-spotted Adalia bipunctata, ten-spotted A. decempunctata, and the invasive Asian ladybird Harmonia axyridis. In gardens and fields they destroy large numbers of aphids, especially during mass reproduction of the pest. Some species specialize on certain prey: Rodolia cardinalis is used to control the Australian cottony cushion scale, Cryptolaemus montrouzieri to control mealybugs in greenhouses (Van Emden, 2013; Kemble et al., 2022).

However, not all coccinellids are beneficial. The genus Epilachna and some other species are phytophagous and can damage crops; for example, the Mexican bean beetle Epilachna varivestis seriously damages legumes (Van Emden, 2013). In addition, Harmonia axyridis can displace local species and damage grapes, worsening wine taste (McGavin and Davranoglou, 2022). Therefore, accurate species identification is of practical importance.

Carabidae (ground beetles)

Ground beetles are a large family numbering more than 40,000 species worldwide. They are predominantly terrestrial predators active at night. Adult beetles and their larvae feed on eggs, larvae and pupae of Diptera, caterpillars, aphids, slugs, wireworms and other invertebrates. Many species are generalists and can consume both animal and plant food (Van Emden, 2013).

Ground beetles play an important role in agrocenoses as natural enemies of pests. For example, they destroy eggs of cabbage fly, bean seed fly and cutworms; adults can climb plants and feed on aphids. In studies they are often used as a “model” group of beneficial arthropods because they are easily recorded using pitfall traps (Van Emden, 2013). However, their effectiveness depends on habitat structure, availability of shelters and pesticide load.

Staphylinidae (rove beetles)

Staphylinidae is one of the largest beetle families, including more than 63,000 species. They are characterized by an elongated body and very short elytra, so that most of the abdomen remains exposed. Many staphylinids are predators or saprophages living in soil, litter, manure and decaying plant residues. They feed on small invertebrates, including Diptera larvae, springtails, mites, nematodes, as well as aphids and their larvae (Van Emden, 2013).

The best-known genera: Stenus, Tachyporus, Ocypus (including the “devil’s coach horse” Ocypus olens). Tachyporus is often found on the soil surface in agrocenoses and can feed on aphids, as well as fungal spores. Staphylinid larvae are active predators, often living in the same habitats as adults. Due to their abundance and diversity, staphylinids make a noticeable contribution to natural regulation of pest abundance, especially in soil and on its surface (Van Emden, 2013).

Anthocoridae (Orius and Anthocoris)

Anthocoridae is a family of small predatory bugs widely used in biological control. The best-known species are of the genus Orius: O. insidiosus, O. laevigatus, O. majusculus, O. albidipennis. These bugs feed on thrips, mites, aphids, small caterpillars and insect eggs. They actively search for prey in flowers, on leaves and in leaf axils. Orius is successfully used in greenhouses to control western flower thrips on vegetable and ornamental crops (Kemble et al., 2022; Akhatov et al., 2013).

Anthocoridae also include species of the genus Anthocoris, for example A. nemoralis, which is used to control pear psylla. These bugs are sensitive to insecticides, so selective preparations must be used in biocontrol programs. To support their populations, it is recommended to sow nectar-bearing plants and avoid broad-spectrum treatments (Akhatov et al., 2013; Van Emden, 2013).

Miridae (predatory plant bugs)

Miridae is a large family of Hemiptera, including both phytophages and predators. Predatory plant bugs of the genera Macrolophus and Nesidiocoris (for example, Macrolophus pygmaeus, Nesidiocoris tenuis) are zoophytophages: they feed on both animal and plant food. In greenhouses they effectively control whiteflies, aphids, thrips, spider mites, leafminers and even caterpillars of the tomato leafminer (Tuta absoluta) (Akhatov et al., 2013; Vallad et al., 2018).

These bugs are well adapted to pubescent plants such as tomato and can persist in the crop for a long time when alternative prey and plant sap are available. However, at high density and lack of animal food they can damage plants, causing necrosis and fruit deformation. Therefore, their release requires monitoring and population management (Akhatov et al., 2013; Vallad et al., 2018).

Nabidae (damsel bugs)

Nabidae is a family of predatory bugs living in herbage, fields, meadows and gardens. They feed on aphids, caterpillars, psyllids, leafhoppers, mites and other soft-bodied invertebrates. Damsel bugs are active throughout the season and can make a significant contribution to reducing pest abundance in open ground. They are sensitive to insecticides, so their conservation requires limiting chemical treatments (Kemble et al., 2022; Van Emden, 2013).

Opiliones (harvestmen)

Harvestmen are an order of arachnids externally resembling spiders with very long and thin legs. However, unlike spiders, their body is not divided into two parts but forms a single oval structure. Harvestmen are not venomous and do not build webs. They live in forest litter, under stones, in grass, feeding on small invertebrates, carrion and plant residues. In agrocenoses they participate in the decomposition of organic matter and regulation of small soil invertebrate abundance (Van Emden, 2013).

Pseudoscorpiones (pseudoscorpions)

Pseudoscorpions are small arachnids externally resembling scorpions but without a tail and sting. Their pedipalps are enlarged and resemble claws. They live under bark, in forest litter, in bird and mammal nests, in soil. Pseudoscorpions are predators feeding on small mites, springtails, insect larvae and other small invertebrates. They can be useful in agrocenoses as natural regulators of soil pest abundance, although their role is insufficiently studied (Van Emden, 2013).

Syrphidae (hoverflies)

Hoverflies are one of the most important families of pollinators among Diptera. Adults feed on nectar and pollen and often visit flowers with open, easily accessible nectaries. They are especially active in cool and cloudy weather, when honey bees and bumblebees fly little. This makes hoverflies indispensable pollinators in regions with cool climates and in early spring (Van Emden, 2013; Kemble et al., 2022).

Hoverflies pollinate many crops: rapeseed, mustard, carrot, dill, parsley, coriander, fruit and berry plants, clover, alfalfa. In studies on seed plantings of Apiaceae, hoverflies are among the most frequent and effective pollinators along with bees and other Diptera (Geoffriau and Simon, 2021). In experiments with rapeseed and mustard, hoverflies provided a significant part of pollination, especially under conditions unfavorable for bees (Abrol, 2009).

Hoverfly larvae occupy different ecological niches: many prey on aphids and other soft-bodied insects; others develop in decaying plant residues, water or ant nests. Predatory hoverfly larvae are important entomophages complementing the activity of green lacewings, ladybirds and predatory bugs (Van Emden, 2013).

Bombyliidae (bee flies)

Bee flies are large, often fluffy flies externally resembling bees or bumblebees. Adults feed on nectar and are pollinators of many plants, including fruit, vegetable and ornamental crops. Bee fly larvae are parasitoids or hyperparasitoids developing in nests of solitary bees, wasps, and also in grasshopper egg pods. Due to their hairiness, bee flies carry a large amount of pollen and can be effective pollinators in arid regions (Van Emden, 2013; McGavin and Davranoglou, 2022).

Bibionidae (March flies, or fever flies)

March flies are among the first insects to appear in spring. Adults feed on nectar and pollen and often form mass aggregations on flowering trees and shrubs. They can be important pollinators of fruit crops in early spring, when other pollinators are still little active. March fly larvae develop in soil, feed on plant residues and can be secondary pests of lawns and root crops (Van Emden, 2013).

Calliphoridae, Muscidae and other Diptera

Many flies from the families Calliphoridae (blow flies), Muscidae (house flies), Tachinidae (tachinids) and others also visit flowers and participate in pollination. They are less specialized than bees and hoverflies but can be important for plants with open, small flowers, for example Apiaceae, Asteraceae and Brassicaceae. In seed production of carrot, onion, cabbage and other crops, flies are often among the main pollinators along with bees (Geoffriau and Simon, 2021; Abrol, 2009).

Tachinids are predominantly parasitoids of butterfly caterpillars and other insects; adults feed on nectar and can be pollinators. However, their main role in agrocenoses is biological pest control (Van Emden, 2013; McGavin and Davranoglou, 2022).

Butterflies (Rhopalocera)

Butterflies are diurnal pollinators visiting flowers with deep corollas and abundant nectar. They possess a long proboscis allowing them to reach nectar from difficult-to-access flowers. Butterflies pollinate many wild and cultivated plants: alfalfa, clover, pea, bean, sunflower, viper’s bugloss, cornflower, lavender, buddleia and others. However, in agrocenoses their role is usually smaller than that of bees and hoverflies, due to lower abundance and greater confinement to natural habitats (Van Emden, 2013; McGavin and Davranoglou, 2022).

Butterflies are sensitive to pesticides and habitat loss. Their conservation requires nectar-bearing plants, host plants for caterpillars and areas with natural vegetation (Ghersa and Martinez-Ghersa, 2019).

Moths (Heterocera)

Many moths are also pollinators, especially nocturnal species. They visit flowers with light coloration and strong aroma, often opening at dusk or at night. Some plants are specialized for pollination by moths: for example, yucca is pollinated by moths of the genus Tegeticula, and some cacti and orchids by nocturnal butterflies. In agrocenoses, moths can pollinate tobacco, petunia, some fruit and berry crops, but their contribution is usually small (Van Emden, 2013; McGavin and Davranoglou, 2022).

It should be noted that many moths are pests (codling moths, leafrollers, cutworms, leaf-mining moths), and their larvae damage crops. Therefore, when assessing the role of Lepidoptera in an agrocenosis, it is necessary to take into account both the positive (pollination) and negative (phytophagy) significance of different species (Van Emden, 2013; Akhatov et al., 2013).

General characteristics

Beetles are one of the most ancient orders of pollinators. Many beetles visit flowers and feed on pollen, nectar or flower tissues. In tropical and subtropical ecosystems, beetles play an important role in pollinating magnolias, water lilies, some palms, cycads and other ancient plant groups. In temperate latitudes, beetles also visit flowers, but their contribution to pollination of crops is usually smaller than that of bees, hoverflies and butterflies (Van Emden, 2013; McGavin and Davranoglou, 2022).

Most important families

Nitidulidae (sap beetles) — small beetles often found on flowers. They feed on pollen and nectar and can be pollinators of fruit, berry and vegetable crops. However, some species (for example, pollen beetles, Meligethes aeneus) are pests of rapeseed and other crucifers: adult beetles feed on pollen and damage buds, reducing seed yield (Van Emden, 2013; Abrol, 2009).

Scarabaeidae (scarab beetles) — large beetles, many of which feed on flowers and can be pollinators. For example, flower chafers (Cetonia, Oxythyrea) visit flowers of fruit and ornamental plants. However, their larvae (white grubs) are soil pests damaging roots (Van Emden, 2013).

Cerambycidae (longhorn beetles) — some species feed on pollen and nectar on flowers and can participate in pollination. However, their larvae are xylophages damaging wood (Van Emden, 2013; McGavin and Davranoglou, 2022).

Cantharidae (soldier beetles) and Melyridae — predatory and phytophagous beetles often found on flowers. They feed on pollen, nectar and small insects and can be both pollinators and entomophages (Van Emden, 2013).

Importance for agriculture

Overall, beetles as pollinators of crops are inferior to bees, bumblebees, hoverflies and butterflies. However, in some crops and regions their role can be noticeable. For example, in tropical cocoa and coffee plantations, beetles participate in pollination along with other insects. In temperate latitudes, beetles can pollinate apple, pear, cherry, raspberry, blackberry, as well as many wild plants (Van Emden, 2013; McGavin and Davranoglou, 2022).

General characteristics

Thrips are small insects with fringed wings, many of which are phytophages. However, some thrips species visit flowers and feed on pollen, participating in pollination. For example, thrips of the genus Thrips and Frankliniella can transfer pollen to stigmas, especially in flowers with small anthers and open nectaries (Van Emden, 2013; McGavin and Davranoglou, 2022).

Role in pollination

Although thrips are usually considered pests (tobacco thrips, western flower thrips, ornamental thrips), some species can be beneficial as pollinators. The literature describes cases where thrips provide pollination of cocoa, some palms, and wild plants in the tropics. However, their contribution to crop pollination is generally small, and more often they act as pests damaging flowers and fruits (Van Emden, 2013; Akhatov et al., 2013; McGavin and Davranoglou, 2022).

Dual role

Thrips demonstrate a dual role in agrocenoses: on the one hand, they can pollinate some plants; on the other, they damage flowers, fruits and leaves and also transmit viral diseases (for example, tomato spotted wilt virus). Therefore, when assessing their significance, the specific species and crop must be taken into account (Akhatov et al., 2013; Van Emden, 2013).

Birds

Bird pollinators (ornithophily) are distributed mainly in the tropics and subtropics. The best known are hummingbirds (Trochilidae) in the Americas, sunbirds (Nectariniidae) in Africa and Asia, and honeyeaters (Meliphagidae) in Australia. They pollinate many tropical and subtropical crops: banana, papaya, mango, guava, some eucalyptus species. In temperate latitudes, birds practically do not play a role as pollinators (McGavin and Davranoglou, 2022).

Mammals

Mammal pollinators (therophily) include bats (Chiroptera) and some marsupials (for example, possums in Australia). Bats pollinate many tropical plants: agave, baobab, some cacti, durian, rambutan. They are active at night and are attracted by flowers with strong odor, light coloration and abundant nectar. In agrocenoses of tropical regions, bats can make a noticeable contribution to pollination of certain crops (McGavin and Davranoglou, 2022; Van Emden, 2013).

Types of specialization

Relationships between pollinators and plants vary from highly specialized (oligolecty, monotropy) to generalized (polylecty). Specialized pollinators are confined to a narrow range of plants and often possess morphological adaptations: long proboscis, special body structure, behavioral stereotypes. Generalists visit a wide range of plants and provide pollination for most crops (Abrol, 2009; Van Emden, 2013).

Examples of specialization

• Yucca and Tegeticula moths: moths lay eggs in the yucca ovary and simultaneously pollinate it; larvae feed on part of the seeds. This is an obligate mutualism (McGavin and Davranoglou, 2022).
• Fig trees and agaonid wasps: each fig species is pollinated by a specific wasp species; the interdependence is absolute (McGavin and Davranoglou, 2022).
• Alfalfa and leafcutter bees: Megachile rotundata is specialized in pollinating alfalfa; its use allows high seed yields (Van Emden, 2013).
• Tomato and bumblebees: vibratory pollination (buzz pollination) is necessary to release pollen from poricidal anthers; bumblebees are the main pollinators of tomatoes in greenhouses (Vallad et al., 2018).

Importance of specialization for the agronomist

Understanding specialization is important when choosing pollinators for a specific crop. For example, for alfalfa, leafcutter bees are preferable; for tomatoes, bumblebees; for apple, honey bees and solitary Andrena bees; for carrot, hoverflies and flies. Universal pollinators (honey bees) can be used on many crops, but their effectiveness depends on flower attractiveness and competition with wild plants (Borghi et al., 2025; Abrol, 2009; Geoffriau and Simon, 2021).

Fruit crops

Apple, pear, cherry, plum, peach, apricot, almond — all these crops depend on cross-pollination. Main pollinators: honey bees, bumblebees, solitary bees (Andrena, Osmia, Megachile), hoverflies, some beetles. In orchards with high flowering density, 2–4 hives per hectare are recommended; for almond, up to 5–8 hives per hectare (Kemble et al., 2022; Van Emden, 2013).

Vegetable crops

Cucumber, pumpkin, watermelon, melon, pepper, tomato, eggplant — require insect pollination. For cucurbit crops, bees (honey and solitary) and bumblebees are necessary; for tomatoes in greenhouses, bumblebees; for pepper and eggplant, bumblebees and bees. In open ground, hoverflies and wild bees also play an important role (Kemble et al., 2022; Vallad et al., 2018; Akhatov et al., 2013).

Oilseed crops

Rapeseed, sunflower, mustard, flax — pollinated by bees, hoverflies, flies and beetles. Pollination increases seed yield and oil content. For rapeseed, 3–5 hives per hectare are recommended; for sunflower, 2–4 hives per hectare (Abrol, 2009; Kemble et al., 2022).

Forage crops

Alfalfa, clover, sainfoin — pollinated by bees, bumblebees, solitary bees. For alfalfa, leafcutter bees (Megachile rotundata) are critically important; for clover, bumblebees with a long proboscis. Without adequate pollination, seed yield of these crops sharply declines (Van Emden, 2013; McGavin and Davranoglou, 2022).

Morphological identification and its limitations

Traditionally, identification of entomophages and acariphages is carried out by morphological characters: wing structure, venation, antenna shape, setae, coloration, genitalia. For many groups, keys and identifiers exist that allow species to be determined with sufficient accuracy. For example, for braconids and ichneumonids, wing venation characters are important: presence or absence of the second transverse mediocubital vein (2m-cu), position of the radial-medial vein (r-m) on the hindwing (Van Emden, 2013). For chalcidoids — structure of antennae, forewing venation, abdomen shape. For phytoseiids — location and number of setae on the idiosoma, cheliceral structure, spermatheca shape (Akhatov et al., 2013; Van Emden, 2013).

However, morphological identification has limitations. Many species are cryptic, that is, externally almost indistinguishable but genetically and ecologically distinct. For example, the complex Aphidius colemani / A. matricariae / A. transcaspicus includes species that differ in male genitalia and molecular markers, but females are often difficult to identify. The complex Trichogramma evanescens includes several sibling species differing in biochemical and molecular characters. Encarsia formosa and related species also require microscopic analysis (Van Emden, 2013; McGavin and Davranoglou, 2022). In such cases, the morphological method is insufficient, and additional approaches are needed.

Cryptic species, biotypes and races

A special difficulty is presented by intraspecific groupings: biotypes, races, strains. In parasitoids and predators, differences are often observed in preferred hosts, resistance to pesticides, temperature requirements, fecundity and behavior. For example, Trichogramma evanescens has several strains differing in effectiveness against different Lepidoptera. Phytoseiulus persimilis has races adapted to different spider mite species and different temperature conditions (Akhatov et al., 2013). Aphidius colemani may include biotypes specialized on different aphid species. Macrolophus pygmaeus and M. caliginosus were long considered one species, but molecular data showed their distinctness (Vallad et al., 2018).

For biocontrol practice, it is important not only to identify the species but also to choose the correct biotype or strain adapted to local conditions and the target pest. Using the “wrong” biotype can lead to reduced effectiveness or undesirable side effects.

Molecular identification methods

Modern systematics and biocontrol widely use molecular methods: polymerase chain reaction (PCR), DNA sequencing, DNA barcoding, analysis of ITS, COI, microsatellites, RAPD, AFLP. These methods allow:

• distinguishing cryptic species;
• identifying biotypes and races;
• determining the origin of introduced populations;
• assessing genetic diversity and inbreeding depression in laboratory cultures;
• diagnosing parasitoids inside hosts without rearing them;
• analyzing gut contents of predators to study their diet (Albajes and Madeira, 2019; McGavin and Davranoglou, 2022).

For example, for identifying Trichogramma species, ITS2 and COI are used; for phytoseiids, ITS and 12S rRNA; for braconids, COI and 28S rRNA. Molecular methods are especially important in quarantine checks, when the species of an imported agent must be determined quickly and accurately (Van Emden, 2013; Albajes and Madeira, 2019).

Deposition and quality of source material

Any biocontrol program should begin with deposition of reference specimens in museum collections and creation of genetic banks. This allows subsequent verification of the identity of released organisms, tracking their origin and avoiding errors. It is also important to control the quality of laboratory cultures: check fecundity, sex ratio, size, searching ability and resistance to diseases. Long-term rearing in the laboratory can lead to inbreeding depression and loss of useful traits (Van Emden, 2013; Albajes and Madeira, 2019).

Types of specificity

The specificity of parasitoids and predators varies from narrow (monophagy, oligophagy) to broad (polyphagy). Narrowly specialized species infect one or several closely related host species; polyphages infect a wide range of species from different families and orders. For biocontrol, narrowly specialized species are preferable because they do not destroy nontarget organisms and do not disturb ecological balance. However, narrow specificity limits the use of an agent only to those agrocenoses where its host is present. Polyphages are more universal but may attack beneficial species, including other entomophages and pollinators (Van Emden, 2013; Albajes and Madeira, 2019).

Classical biocontrol and risk to nontarget species

Classical biocontrol involves the introduction of exotic natural enemies to control invasive pests. This method has produced many successful examples: Rodolia cardinalis against the Australian cottony cushion scale, Anagyrus lopezi against the cassava mealybug, Encarsia formosa against greenhouse whitefly (Van Emden, 2013; McGavin and Davranoglou, 2022). However, the introduction of exotic species carries risks: they may attack nontarget species, compete with local entomophages, spread beyond the agrocenosis and disrupt ecosystems. The example of Harmonia axyridis — the Asian ladybird introduced to control aphids but becoming an invasive species that displaces local coccinellids and damages grapes — shows the need for careful risk assessment (McGavin and Davranoglou, 2022).

Methods for assessing specificity

Before release, laboratory and field tests are conducted:

• No-choice tests: the predator or parasitoid is offered only a nontarget species; ability to infect and develop is assessed.
• Choice tests: target and nontarget species are offered simultaneously; preference is assessed.
• Field tests: attack on nontarget species is assessed under semi-field or field conditions.
• Molecular gut content analysis: allows determining which species were eaten by a predator in nature.
• Life table analysis: assesses the effect of the agent on nontarget species populations (Albajes and Madeira, 2019; Van Emden, 2013).

Based on these data, a risk assessment is constructed: probability of establishment of the agent in a new region, its spread, impact on nontarget species and possibility of pathogen transfer. In a number of countries there are legislative requirements: import permits, quarantine, ecological risk assessment. International organizations (IOBC/WPRS, EPPO, FAO) develop standards and guidelines for the safe use of biocontrol (Albajes and Madeira, 2019; Van Emden, 2013).

Climatic compatibility and ecological requirements

Besides specificity, it is important to assess the climatic compatibility of the agent with the release region: temperature thresholds, humidity, photoperiod, availability of alternative prey, ability to diapause. For example, Phytoseiulus persimilis is effective at 25–30 °C and humidity above 70%, but works poorly at low humidity. Neoseiulus californicus is more resistant to dryness and high temperatures (Akhatov et al., 2013). Trichogramma has different species and strains adapted to different climatic zones (Van Emden, 2013). Incorrect choice of agent can lead to its death or ineffectiveness.

Compatibility with pesticides

One of the main factors limiting the effectiveness of biocontrol is the use of pesticides. Many insecticides and acaricides are toxic to entomophages. To assess compatibility, standardized IOBC tests are used, which classify preparations by degree of harmful effect on beneficial species: from harmless (L) to highly toxic (H). In tables of relative toxicity (for example, in Kemble et al., 2022) it is indicated that pyrethroids, neonicotinoids and organophosphates often have a high level of impact on predatory mites, green lacewings, parasitoids and pollinators, whereas avermectins, spinetoram and methoxyfenozide have low or medium (Kemble et al., 2022; Akhatov et al., 2013).

When planning treatments it is necessary to:

• choose selective preparations;
• apply them in the evening, after pollinator flight has ended;
• avoid treating flowering crops;
• use economic thresholds;
• alternate preparations of different classes to prevent resistance (Albajes and Madeira, 2019; Kemble et al., 2022).

Compatibility with other entomophages

When several biocontrol agents are used together, intraguild predation (eating of some entomophages by others), competition for prey and mutual interference are possible. For example, predatory bugs Macrolophus can eat larvae of green lacewings and predatory mites; Orius can feed on eggs of other entomophages. To reduce risks, it is necessary to select compatible species, regulate rates and timing of release, and create shelters and alternative food sources (Akhatov et al., 2013; Vallad et al., 2018). In greenhouses, combinations are often used: Encarsia formosa + Eretmocerus eremicus against whitefly; Phytoseiulus persimilis + Neoseiulus californicus against spider mites; Aphidius colemani + Aphidoletes aphidimyza against aphids (Akhatov et al., 2013).

Compatibility with pollinators

The use of bumblebees and bees in greenhouses imposes restrictions on insecticide application. Neonicotinoids, pyrethroids and organophosphates are highly toxic to pollinators. Therefore, in greenhouses with bumblebees, only selective preparations compatible with pollinators should be used, and they should be applied in the evening when bumblebees are inactive (Vallad et al., 2018; Kemble et al., 2022). Similarly, in orchards with bees and solitary bees, treatments during flowering should be avoided and preparations with low toxicity for pollinators should be used (Abrol, 2009; Kemble et al., 2022).

Compatibility with agrotechnics and GM crops

Agrotechnical practices can both promote and hinder biocontrol. Minimum tillage, mulching, cover crops, crop rotation, creation of flower strips and hedgerows support beneficial fauna (Ghersa and Martinez-Ghersa, 2019; Albajes and Madeira, 2019). In contrast, intensive tillage, monocultures, widespread use of herbicides and insecticides reduce entomophage abundance.

GM crops expressing Bacillus thuringiensis (Bt) can be compatible with biocontrol because Bt toxins are specific to certain insect groups and do not affect most entomophages. However, possible effects on nontarget species and on parasitoids developing in Bt-resistant caterpillars must be taken into account. Studies show that Bt crops are generally compatible with biological control and can reduce the need for insecticides (Albajes and Madeira, 2019).

Rearing methods

Mass rearing of entomophages is the basis of their commercial use. For rearing, the following are needed:

• target host (for example, Tetranychus urticae for Phytoseiulus persimilis; Trialeurodes vaporariorum for Encarsia formosa; Schizaphis graminum for Aphidius colemani);
• factitious host (for example, eggs of Ephestia kuehniella for Trichogramma and green lacewings; Aphis fabae for Aphidoletes aphidimyza);
• artificial diets (for some predatory mites and bugs);
• plant substrates (for phytoseiids and predatory bugs);
• cultivation conditions: temperature, humidity, photoperiod, density, food quality.

For example, Trichogramma is reared on eggs of the Mediterranean flour moth Ephestia kuehniella; Phytoseiulus persimilis on spider mites on bean or soybean; Aphidius colemani on grain aphid on barley or wheat; Encarsia formosa on greenhouse whitefly on tobacco or tomato (Akhatov et al., 2013; Van Emden, 2013). In some cases artificial nutrient media are used, but they are still less widespread.

Quality control

The quality of biomaterial is a critical factor of success. Parasitoids and predators reared in the laboratory for many generations may lose the ability to search for hosts, reduce fecundity, viability and resistance to stresses. For quality control, standardized tests are used:

• fecundity and sex ratio;
• duration of development;
• body size;
• searching ability;
• resistance to pesticides;
• genetic diversity (molecular markers).

It is important to periodically refresh laboratory cultures with wild individuals or exchange genetic material between laboratories (Van Emden, 2013; Albajes and Madeira, 2019).

Storage and transportation

To synchronize releases with pest phenology, biomaterial is often stored in a state of diapause or at low temperatures. For example, Trichogramma is stored as diapausing pupae at 10–12 °C for several months. Phytoseiulus persimilis is stored at 10–12 °C for 1–2 weeks. Encarsia formosa as whitefly mummies at 10–12 °C. During transportation, optimal temperature and humidity must be maintained, avoiding overheating and drying (Akhatov et al., 2013; Van Emden, 2013).

Release strategies

There are three main strategies:

• Inoculative release: a small number of individuals are released to establish a population that will reproduce and control the pest during the season. Used in greenhouses for Encarsia formosa, Phytoseiulus persimilis, Aphidius colemani.
• Inundative release: mass release for immediate pest suppression. Used at high pest density, for example for Trichogramma in fields, Phytoseiulus persimilis in spider mite foci.
• Seasonal colonization: regular releases during the season to maintain entomophage abundance at the necessary level. Used for Aphidius colemani, Neoseiulus cucumeris, Orius (Akhatov et al., 2013; Van Emden, 2013).

Release rates depend on crop, pest density, temperature, humidity and developmental stage of the entomophage. For example, Phytoseiulus persimilis is released at a predator:prey ratio of 1:5–1:20; Encarsia formosa at 5,000–100,000 individuals per 1 ha; Aphidius colemani at 5,000–10,000 individuals per 1 ha at weekly intervals (Akhatov et al., 2013). It is important to distribute biomaterial evenly over the area, taking into account wind direction, time of day and presence of flowering plants.

Before release

Before release it is necessary to assess:

• species composition of pests;
• pest density and distribution;
• presence of natural enemies;
• economic threshold of harmfulness (ETH);
• climatic conditions;
• compatibility with planned pesticides.

Monitoring is carried out using visual inspections, yellow sticky traps, pheromone traps, soil traps and sentinel plants (Albajes and Madeira, 2019; Kemble et al., 2022).

After release

After release, the following are assessed:

• pest abundance;
• level of parasitism (share of infected hosts);
• abundance and spread of the entomophage;
• survival and reproduction of the entomophage;
• crop damage;
• economic effectiveness.

To assess parasitism, visual methods are used (dissection of hosts, counting mummies), molecular methods (PCR to determine the parasitoid species inside the host), and sentinel hosts (laboratory prey exposed in the field). For predators — visual counts, traps, gut content analysis (Albajes and Madeira, 2019; Van Emden, 2013).

Strategy adjustment

Based on monitoring, decisions are made:

• increase or decrease release rate;
• change release frequency;
• replace the entomophage species;
• apply a selective pesticide;
• improve conditions for entomophage conservation (flower strips, banker plants);
• adjust agrotechnics.

It is important to document all observations and decisions in order to accumulate experience and improve biocontrol effectiveness (Albajes and Madeira, 2019; Kemble et al., 2022).

Flower strips and nectar-bearing plants

One of the most effective ways to support beneficial arthropods is the creation of flower strips (wildflower strips, insectary plantings) along fields, in gardens and greenhouses. Such strips provide a continuous source of nectar and pollen for adult parasitoids, predators and pollinators, and also serve as shelter for nesting and overwintering (Kemble et al., 2022; Albajes and Madeira, 2019). Studies show that flower strips increase the abundance and activity of natural enemies of pests, including hoverflies, green lacewings, predatory bugs, spiders and parasitoid Hymenoptera (Ghersa and Martinez-Ghersa, 2019).

In Switzerland, the practice of “weed strip management” — creating strips with diverse native flowering plants — increased the activity of ground beetles (Carabidae), spiders (Araneida), Nabidae bugs, Diptera Dolichopodidae and Syrphidae (Ghersa and Martinez-Ghersa, 2019). For aphid control, it is recommended that 5–10% of the area be sown with wild flowers and grasses; this supports aphidophages and reduces pest abundance (Ghersa and Martinez-Ghersa, 2019). In greenhouses and gardens, “banker plants” are also used, which support the reproduction of entomophages through alternative prey or pollen (Vallad et al., 2018).

It is important to select mixtures of plants with different flowering times to ensure continuous food supply throughout the season. Native species are recommended: clover, phacelia, mustard, sweet clover, cornflower, chamomile, sunflower, dill, coriander, carrot (Geoffriau and Simon, 2021; Kemble et al., 2022). For pollinators, plants with open nectaries and abundant pollen are especially valuable; for parasitoids, plants with small flowers and accessible nectar (Abrol, 2009).

Hedgerows, buffer zones and landscape elements

Hedgerows, forest belts, buffer zones and areas of natural vegetation create stable habitats for beneficial arthropods, providing shelters, overwintering sites and alternative food sources. Landscape heterogeneity and habitat mosaicism positively affect the diversity and effectiveness of natural enemies, especially those that need permanent structures for nesting and surviving unfavorable periods (Ghersa and Martinez-Ghersa, 2019; Albajes and Madeira, 2019).

Buffer zones along fields and water bodies reduce pesticide drift, erosion and water pollution while supporting beneficial fauna. In integrated production, IOBC/WPRS recommends allocating at least 5% of farm area to ecological compensation — hedgerows, natural areas, field margins where fertilizers and pesticides are not applied (Avilla and Riedl, 2003). This creates a “network” of habitats connecting agrocenoses with natural ecosystems and supporting metapopulations of entomophages and pollinators.

Nesting houses, banker plants and shelters

For solitary bees and bumblebees, artificial nests can be created: “bee hotels” made of drilled wooden blocks, bundles of reeds, ceramic tubes; bumblebee boxes — boxes with dry grass or moss buried in the ground (Van Emden, 2013; McGavin and Davranoglou, 2022). For predatory mites and bugs, banker plants are used, which support their reproduction at low pest density (Vallad et al., 2018). In greenhouses, pollen supplementation (for example, alder or birch) is used for phytoseiids and Orius, as well as bran with predatory mites (Akhatov et al., 2013).

Soil predators (ground beetles, rove beetles, spiders, Laelapidae and Macrochelidae mites) need plant residues, mulch, cover crops and areas with minimum tillage. Preservation of litter and the topsoil layer promotes their survival and reproduction (Van Emden, 2013; Ghersa and Martinez-Ghersa, 2019).

Vegetation management and crop rotation

Agrotechnical practices can both support and suppress beneficial fauna. Crop rotation including legumes, cover crops and perennial grasses improves soil structure, increases biodiversity and reduces the abundance of specialized pests (Ghersa and Martinez-Ghersa, 2019). Cover crops (clover, vetch, phacelia, mustard) provide nectar and pollen, as well as shelters for entomophages; it is important to choose species that do not become reservoirs of pests (Kemble et al., 2022).

Minimum tillage, mulching and preservation of plant residues promote the survival of soil predators and saprophages. In contrast, intensive plowing, monocultures and clean fallow reduce the abundance of beneficial arthropods (Ghersa and Martinez-Ghersa, 2019; Albajes and Madeira, 2019). Intercropping and strip cropping can reduce pest infestation by “diluting” the resource and supporting natural enemies (Ghersa and Martinez-Ghersa, 2019). “Push–pull” strategies using repellent plants and trap plants also contribute to pest regulation and conservation of beneficial fauna (Ghersa and Martinez-Ghersa, 2019).

Principles of integrated protection

Integrated plant protection (IPM) is the basis for conserving beneficial arthropods. IPM involves combining biological, cultural, physical and chemical methods, with chemical treatments applied only when the economic threshold of harmfulness is exceeded (Albajes and Madeira, 2019; Kemble et al., 2022). Key elements of IPM: regular monitoring, precise pest identification, use of resistant varieties, conservation of natural enemies, selective preparations and minimization of impact on nontarget organisms.

Impact of pesticides on beneficial arthropods

Pesticides can have both acute and sublethal effects on beneficial fauna: impaired orientation, reduced fecundity, worsened searching ability, changed behavior, suppressed immunity. Broad-spectrum insecticides are especially dangerous — pyrethroids, neonicotinoids, organophosphates, carbamates. They are highly toxic to pollinators, parasitoids, predatory mites, green lacewings, hoverflies, spiders and ground beetles (Kemble et al., 2022; Akhatov et al., 2013). In tables of relative toxicity (for example, Kemble et al., 2022) it is indicated that most pyrethroids and neonicotinoids have a high level of impact on key groups of natural enemies, whereas avermectins, spinetoram, methoxyfenozide and some biopreparations have low or medium.

Choosing selective preparations and application tactics

To conserve beneficial arthropods, it is recommended to:

• choose selective preparations safe for entomophages and pollinators;
• apply them in the evening, after bee and bumblebee flight has ended;
• avoid treating flowering crops;
• use economic thresholds and conduct only targeted treatments;
• alternate preparations of different classes to prevent resistance;
• use buffer zones and avoid drift onto neighboring areas (Kemble et al., 2022; Albajes and Madeira, 2019).

In greenhouses with bumblebees and predatory mites, only compatible preparations should be used; many neonicotinoids are prohibited for use under such conditions (Vallad et al., 2018; Akhatov et al., 2013). In orchards with bees and solitary bees, treatments during flowering should be avoided and preparations with low toxicity for pollinators should be chosen (Abrol, 2009; Kemble et al., 2022). It is also important to protect water sources and not leave puddles with pesticides that may attract bees (Kemble et al., 2022).

Organic farming

Organic farming is based on avoiding synthetic pesticides and mineral fertilizers, maintaining soil fertility, biodiversity and natural regulatory mechanisms. Organic farms are generally more favorable for beneficial arthropods: higher plant diversity, more flower strips, lower pesticide load (Weibel and Haseli, 2003; Ghersa and Martinez-Ghersa, 2019). However, problems are possible in organic farming: the use of sulfur, copper preparations and some biopesticides can be toxic to bees and entomophages. Therefore, even in organic farming, selectivity and timing of treatments must be observed (Weibel and Haseli, 2003; Akhatov et al., 2013).

Integrated protection and integrated production

Integrated production (IP) and integrated plant protection (IPM) are broader concepts than simply avoiding pesticides. They involve:

• conservation and enhancement of biological diversity;
• use of resistant varieties;
• crop rotation and agrotechnical methods;
• biological control;
• selective pesticides only when necessary;
• monitoring and economic thresholds;
• ecological compensation zones (at least 5% of area) (Avilla and Riedl, 2003; Albajes and Madeira, 2019).

IOBC/WPRS has developed guidelines for integrated apple production, including conservation of natural enemies, introduction of phytoseiids, creation of shelters for beneficial fauna, and use of selective preparations (Avilla and Riedl, 2003). In greenhouses, integrated protection combines releases of entomophages (Encarsia, Eretmocerus, Phytoseiulus, Neoseiulus, Aphidius, Aphidoletes, Orius, Macrolophus) with selective preparations and monitoring (Akhatov et al., 2013; Vallad et al., 2018).

Compatibility of methods

Conservation of beneficial arthropods requires compatibility of all protection methods. Biological control, resistant varieties, agrotechnics and selective pesticides must complement each other, not conflict. For example, the use of Bt crops can reduce the need for insecticides and be compatible with biocontrol, but possible effects on nontarget species must be considered (Albajes and Madeira, 2019). GM crops resistant to pests can reduce pesticide load but require monitoring and risk assessment. In general, the higher the biodiversity and the more complex the agroecosystem, the more resistant it is to pests and the less it needs chemical treatments (Ghersa and Martinez-Ghersa, 2019; Altieri, 1999).

Importance of monitoring

Monitoring is the basis of adaptive management. Without regular observations it is impossible to assess the abundance of beneficial arthropods, the effectiveness of releases, the impact of agrotechnics and pesticides, or to detect problems in time. Monitoring allows informed decisions: whether to release entomophages, apply pesticides, create additional habitats or change crop rotation (Albajes and Madeira, 2019; Kemble et al., 2022).

Monitoring methods

To assess beneficial fauna, the following are used:

• visual inspections of plants (eggs, larvae, pupae, adults);
• yellow sticky traps for whiteflies, thrips, aphids and leaf-mining flies;
• pheromone traps for Lepidoptera and other pests;
• soil traps (pitfall traps) for ground beetles, rove beetles and spiders;
• sentinel prey (laboratory eggs or larvae exposed in the field);
• molecular methods (PCR, sequencing) for species identification and analysis of predator diet;
• analysis of gut contents and feces;
• remote methods (drones, spectral imaging) (Albajes and Madeira, 2019; McGavin and Davranoglou, 2022; Van Emden, 2013).

For pollinators, standardized transect counts, observations on flowers, pan traps, as well as nesting houses and banker plants for assessing occupancy are used (Kemble et al., 2022; McGavin and Davranoglou, 2022).

Citizen science

Citizen science is increasingly used to monitor biodiversity and beneficial arthropods. Volunteers help collect data on visitation rates, nesting, species distribution and phenology. International platforms exist: iNaturalist, BeeWatch, Global Pollinator Watch, eBird, BugGuide. In agrocenoses, farmers and gardeners can participate in monitoring pollinators and entomophages using simple protocols and mobile applications. This allows large data sets to be accumulated, trends to be identified and adaptive decisions to be made (McGavin and Davranoglou, 2022; Kemble et al., 2022).

Adaptive management

Based on monitoring, adaptive management is built:

• if entomophage abundance is low, additional habitats are created or releases are carried out;
• if the pest exceeds the ETH, selective preparations are applied;
• if pollinators are insufficient, nectar-bearing plants are sown or hives are placed;
• if biocontrol effectiveness decreases, causes are analyzed (hyperparasitoids, pesticides, climate) and the strategy is adjusted (Albajes and Madeira, 2019; Kemble et al., 2022).

Documenting observations and decisions allows experience to be accumulated, staff to be trained and farm sustainability to be increased.