Pests

1.1. Holes and Chewing

This is the most visible type of damage.

What it looks like: Through-holes of various sizes and shapes appear on the leaves. Sometimes the leaf blade is eaten almost entirely, leaving only the main veins (skeletonization). Leaf edges may appear ragged, as if something has been gnawing on them.

Who does this: This is almost always caused by pests with chewing mouthparts. Most often, these are larvae and adult beetles (e.g., flea beetles – they leave small holes like shot pellets) or caterpillars (e.g., cutworm caterpillars or beet tortoise beetle). Caterpillars of leaf-chewing cutworms (e.g., turnip moth) can not only damage leaves but also gnaw through petioles at the base, causing wilting (Karataev and Sovetkina, 1984; Akhatov et al., 2013).

Why this matters: If you see holes, the pest is on the surface and can be effectively controlled with contact or stomach insecticides.

1.2. Mining

This is a very characteristic sign that is often confused with diseases.

What it looks like: Winding "corridors," tunnels, or blister-like swellings appear on the leaves, along with dirty-yellow or brown spots. Upon closer inspection, you can see a dark dot or the worm itself inside the tunnel. The surface of the spot is usually thin, as if transparent, and dark excrement of the pest may be visible through it (Akhatov et al., 2013). These are traces of the larva eating the leaf pulp from the inside, leaving the upper and lower skin intact.

Who does this: The main "miner" on beet is the larvae of the beet leaf miner fly (Pegomyia betae and Pegomyia hyoscyami). This is a very dangerous pest, especially in southern regions (Akhatov et al., 2013). Some sources also refer to it as a leaf miner (Rana, 2018).

Why this matters: Mining pests are among the most difficult to control. They are inside the leaf, so contact insecticides cannot reach them. Systemic insecticides, which penetrate plant tissues, are needed for control.

1.3. Sucking

This type of damage is less noticeable but very insidious.

What it looks like: Leaves lose turgor, become pale, turn yellow, curl, or become deformed. A sticky, shiny coating (honeydew) or, conversely, a black sooty mold on the leaves may appear. Plants look stunted and growth is slowed.

Who does this: Insects with piercing-sucking mouthparts. The main pest is the black bean aphid (Aphis fabae). They suck sap from leaves and young shoots (Akhatov et al., 2013; Karataev and Sovetkina, 1984). Also included in this group are beet bugs.

Why this matters: First, aphids are the main vectors of dangerous viral diseases (mosaic, yellows) (Rana, 2018; Akhatov et al., 2013). Second, aphid colonies can grow to enormous sizes, and control measures must be started as early as possible, before mass reproduction occurs.

1.4. Root Damage

This is the most dangerous type of damage because it directly affects yield and root quality.

What it looks like: Grooves, tunnels, deep pits are visible on the root crops, and lateral roots may be gnawed off. Plants begin to wilt for no apparent reason. Root crops are often affected by rots, as pathogens enter through the damage (Ulatowska et al., 2025).

Who does this:

• Larvae of click beetles (wireworms) gnaw tunnels in root crops.
• Mole crickets gnaw roots and stems at the soil surface.
• Larvae of the beet weevil feed on roots.
• Older larvae of the beet moth (Scrobipalpa ocellatella) can bore into the upper part of the root (Akhatov et al., 2013; Ulatowska et al., 2025).

Why this matters: Root damage is almost impossible to treat. Control here is primarily about prevention (agronomy) and protection at the seedling stage. An adult plant with a damaged root system is unlikely to produce a good yield.

Remember: Correct diagnosis is 50% of success. The following chapters will help you become more familiar with each of the mentioned pests and choose the right control strategy.

2.1. Beet Leaf Miner Fly (Pegomya hyoscyami and Pegomya betae)

This is one of the most insidious and dangerous leaf pests, especially in southern regions where it can produce 2-3 generations per season (Akhatov et al., 2013).

How to recognize: If you see dirty-yellow spots on the leaves that turn brown over time and feel blistered to the touch — this is most likely the work of fly larvae (Akhatov et al., 2013). Inside such spots ("mines"), you can see winding tunnels made by the larva eating the pulp. The adult fly is a grey-yellow insect, 6-8 mm long (Akhatov et al., 2013).

Why this happens: The female fly lays eggs on the underside of the leaf. The hatched larva burrows inside and feeds on the parenchyma, leaving the upper skin intact (Akhatov et al., 2013). Up to 30 larvae can inhabit a single leaf, completely destroying its photosynthetic surface.

Life cycle and danger: The pest overwinters as a puparium in the soil at a depth of up to 10 cm. The emergence of flies in spring coincides with cherry blossom. The pest develops in 2-3 generations per season (Akhatov et al., 2013). In dry and hot weather, young larvae often die, but in favorable years, this pest can cause serious damage.

Control measures:

• Agronomy: Deep autumn plowing or digging, which disturbs overwintering sites.
• Chemical method: Since larvae are inside the leaf, contact insecticides are ineffective. It is necessary to use systemic products (e.g., based on dimethoate) that penetrate plant tissues. Treatments are recommended during the fly flight period, before larvae enter the leaf (Akhatov et al., 2013).

2.2. Beet Flea Beetle (Chaetocnema concinna)

This small but very voracious beetle is a real scourge for beet seedlings.

How to recognize: Beetles are small (1.5-2.3 mm), dark bronze or greenish, with jumping hind legs (Akhatov et al., 2013). On leaves and cotyledons, they eat small round pits, not affecting the lower skin. As a result, characteristic "windows" or small through-holes appear on the leaves. During mass reproduction, flea beetles can completely destroy young plants (Akhatov et al., 2013).

Why this is important: The flea beetle is most dangerous from the "fork" stage (cotyledon appearance) until 4-5 true leaves form. In hot, dry weather, its harmfulness increases sharply. Loss of even 50% of seedlings during this period can reduce root yield by a third (Akhatov et al., 2013).

Life cycle: Beetles overwinter under plant debris. In spring, they first feed on weeds (lamb's quarters, goosefoot) and then move to beet seedlings. They lay eggs in the soil, where larvae develop, feeding on small roots (Akhatov et al., 2013).

Control measures:

• Agronomy: Weed control, especially weeds from the Chenopodiaceae family, early sowing for uniform emergence.
• Chemical method: When 3-5 beetles per 1 m² appear, insecticide treatments (e.g., based on pyrethroids) are necessary. Border treatments of fields are also effective, as flea beetles initially colonize the edges (Akhatov et al., 2013).
• Home methods: In private plots, young plants can be dusted with ash or slaked lime to repel the pest (Akhatov et al., 2013).

2.3. Beet Tortoise Beetle (Cassida nebulosa)

This pest often appears in southern regions and can severely damage leaves throughout the season.

How to recognize: Adult beetles have a characteristic shield-like appearance, with a flat-oval body, rusty-brown or greenish color, 6-7 mm long (Akhatov et al., 2013). Larvae are yellow-green, with long tail bristles, onto which they attach their excrement — this is their distinctive feature (Akhatov et al., 2013).

Nature of damage: Beetles gnaw through-holes in leaves. Larvae scrape the parenchyma from the underside of the leaf, leaving the upper transparent skin intact. Severely damaged leaves become lace-like (Akhatov et al., 2013).

Control measures: As with flea beetles, weed control (lamb's quarters) is important, as the pest first multiplies on weeds. At high numbers (more than 1 beetle per plant or more than 20 larvae per 1 m²), insecticide treatments are recommended (Akhatov et al., 2013). The pest also has natural enemies — predatory bugs and Trichogramma wasps.

2.4. Leaf Caterpillars (Cutworms and Others)

This group includes a range of pests, including caterpillars of the turnip moth (Agrotis segetum), meadow moth, and other Lepidoptera.

How to recognize: Caterpillars are worm-like larvae of various colors and sizes. Damage is usually quite visible: leaves are eaten from the edges or completely skeletonized (Karataev and Sovetkina, 1984).

Danger: Caterpillars of cutworms are especially dangerous. Older caterpillars of the turnip moth (brown or grey, up to 5 cm long) are nocturnal and hide in the soil at the base of plants during the day. They gnaw through leaf petioles, stems at the root collar, and even eat pits in the root crops themselves (Akhatov et al., 2013). One caterpillar can destroy 10-15 plants per night (Akhatov et al., 2013).

Control measures:

• Agronomy: Thorough weed control, loosening between rows during caterpillar pupation.
• Biological method: Release of Trichogramma (egg parasitoids) during cutworm egg-laying is effective. Biological products (e.g., based on Bacillus thuringiensis) are also used (Akhatov et al., 2013).
• Chemical method: When younger caterpillars appear, treatments with pyrethroid insecticides are applied. Treatments are best done in the evening when caterpillars come out to feed (Akhatov et al., 2013).

Main takeaway for leaf pests: Regular crop inspection is your primary defense. Identify the type of damage (holes, mining, sucking) and choose the appropriate strategy. Remember that weed control is a key preventive measure for most of them.

3.1. Black Bean Aphid (Aphis fabae)

This is the most common and dangerous sucking pest of beet. It is found everywhere and can cause enormous damage, especially on seed crops (Akhatov et al., 2013).

How to recognize: Aphids are easily visible to the naked eye. They are small (1.5-2.5 mm) insects that gather in large colonies on the underside of leaves, on stems, and on the upper part of root crops. Color can range from black (velvety black) to brown, depending on conditions (Akhatov et al., 2013; Karataev and Sovetkina, 1984). Characteristic signs of infestation: leaves curl, turn yellow, and a sticky sugary coating (honeydew) appears, on which black sooty mold often develops.

Life cycle: This is a very complex cycle. Eggs overwinter on branches of spindle tree, viburnum, and jasmine. In spring, larvae emerge from them, which turn into wingless founding females. They reproduce without fertilization, giving rise to new generations. Then winged dispersal females appear, which fly to beet crops and other plants (Akhatov et al., 2013). During the summer, aphids can produce 10-17 generations! In autumn, winged individuals return to shrubs, where sexual reproduction occurs, and females lay overwintering eggs.

Why this is dangerous:

1. Sap sucking: Mass reproduction of aphids leads to severe plant stunting, growth retardation, leaf curling, and drying (Karataev and Sovetkina, 1984).

2. Virus transmission: Aphids are the main vector of beet mosaic and beet yellows viruses (Beet mosaic virus, Beet yellow virus, Beet mild yellowing virus) (Rana, 2018; Akhatov et al., 2013). This is especially dangerous on seed crops, where viruses can lead to significant seed yield losses.

Control measures:

• Agronomy: Destroy weeds (goosefoot, lamb's quarters, sow thistle) that serve as intermediate hosts for aphids. If shrubs (spindle tree, viburnum) that are primary hosts grow near the field, they should be treated with insecticides early in spring (Akhatov et al., 2013).
• Biological method: Attract natural enemies: ladybirds, lacewings, hoverflies. These entomophages can effectively suppress aphid populations (Akhatov et al., 2013).
• Chemical method: When the first aphid colonies appear, insecticide treatments are necessary. Systemic products (based on dimethoate) are most effective, as they penetrate the plant sap and kill insects when feeding (Akhatov et al., 2013). In private plots, biological products based on avermectin (Fitoverm) can be used (Akhatov et al., 2013).

3.2. Beet Bugs (Grey and Yellow)

In addition to aphids, bugs from the family Miridae can cause serious damage to beet. The most common are the grey beet bug (Polymerus cognatus) and the yellow beet bug (Polymerus vulneratus) (Akhatov et al., 2013).

How to recognize: These are small (3-5.5 mm) insects with an oval body covered in silvery hairs. The grey bug is yellow-brown with black spots, the yellow bug is straw-yellow or greenish (Akhatov et al., 2013). They feed by puncturing plant tissues and sucking out sap.

Nature of damage: Necrotic spots appear at puncture sites on leaves, leaves curl, become distorted, and edges blacken and dry out. Bugs are especially dangerous in dry years, when their harmfulness increases (Akhatov et al., 2013). Like aphids, bugs are vectors of mosaic virus.

Life cycle: Eggs overwinter in the tissues of weed stems (lamb's quarters, amaranth) and alfalfa. In spring, larvae appear on these plants and then move to beet (Akhatov et al., 2013). Bugs produce 2-3 generations per season.

Control measures:

• Agronomy: Weed control, early low mowing of perennial legumes (alfalfa, clover) that serve as pest reservoirs (Akhatov et al., 2013).
• Chemical method: In case of severe infestation, insecticides (e.g., based on dimethoate) are used. Treatments are effective during the mass appearance of larvae on beet.

3.3. Leafhoppers

Leafhoppers are another group of sucking pests that can also transmit viruses, particularly the beet curly top virus (Rana, 2018). Although this group is described in less detail in the provided Russian-language sources, it is important to know they exist and can pose a threat (Rana, 2018). Control measures are similar to those for aphids.

Summary for sucking pests:

The main danger of this group lies in their ability to transmit viruses. Therefore, the main protection strategy should aim not only at killing insects but also at breaking the chain of infection spread: weed destruction, treatment of reservoir shrubs, timely insecticide application, and attracting entomophages. Do not wait until aphids or bugs multiply into huge colonies — control them at the first signs of appearance.

4.1. Wireworms (Larvae of Click Beetles)

Wireworms are larvae of click beetles (Agriotes spp. and others). They are among the most common and dangerous soil pests, damaging seedlings and root crops of beet (Akhatov et al., 2013; Karataev and Sovetkina, 1984).

How to recognize: Wireworm larvae have a characteristic appearance — they are long (up to 10–25 mm), thin, yellow or light brown, with hard chitinous coverings (Akhatov et al., 2013). They feel very rigid to the touch, like wire (hence the name).

Nature of damage: Wireworms gnaw tunnels in germinating seeds, eating embryos and roots. At the seedling stage, they can completely gnaw through the underground part of the stem, leading to plant death. Later, they bore into root crops, making winding tunnels and pits. Damaged root crops lose marketable quality, become deformed, and are often affected by rots (Akhatov et al., 2013). Wireworms are active throughout the growing season (Karataev and Sovetkina, 1984).

Life cycle: Larval development lasts several years (3–5), during which they live in the soil, feeding on plant roots. Adult beetles (click beetles) are not a serious threat to beet (Akhatov et al., 2013).

Control measures:

• Agronomy: This is the foundation. Deep autumn digging (fall plowing) disturbs overwintering sites and brings some larvae to the surface, where they die from frost or desiccation (Akhatov et al., 2013). Crop rotation excluding affected crops also reduces pest numbers. Weed control (especially couch grass) deprives wireworms of additional food sources.
• Chemical method: At high pest numbers, soil-applied insecticides (granular products) are used before sowing. In private plots, baits can be used: pieces of potato or carrot buried in the soil, which are collected and destroyed together with larvae (Karataev and Sovetkina, 1984).

4.2. Mole Cricket (Gryllotalpa gryllotalpa)

The mole cricket is a large (up to 50 mm long) brown insect with powerful digging legs (Akhatov et al., 2013). It is a dangerous polyphagous pest that damages not only beet but also many other vegetable crops.

How to recognize: The mole cricket lives in the soil, digging horizontal tunnels near the surface. A characteristic sign of its presence is loose earthen ridges on the bed surface and clearly visible entrance holes to burrows.

Nature of damage: It gnaws through roots and stems of young plants at the base, and gnaws large cavities in root crops (Akhatov et al., 2013; Karataev and Sovetkina, 1984). Damaged plants quickly wilt and die.

Life cycle: Adults and larvae overwinter in the soil at depths of up to 1 meter. In spring, they emerge to the surface and begin actively feeding and reproducing.

Control measures:

• Agronomy: Deep autumn digging destroys nests and overwintering chambers. Manure applied to the soil can attract mole crickets, so it is best applied only in decomposed form (Karataev and Sovetkina, 1984).
• Traps and baits: In early spring, fresh manure piles are laid out (attracting mole crickets for egg-laying), which are then checked and pests destroyed. Food baits (grain mixed with insecticide) are also effective.
• Chemical method: In case of mass reproduction, poisoned baits based on zinc phosphide (Karataev and Sovetkina, 1984) or soil-applied insecticides are used.

4.3. Beet Weevil (Bothynoderes punctiventris)

This pest is especially dangerous in southern regions, during dry years. Both adult beetles and their larvae cause damage (Akhatov et al., 2013).

How to recognize: Beetle is 10–13 mm long, greyish-brown. Larva is white, legless, curved, living in the soil.

Nature of damage: Beetles in spring eat seedlings ("fork" stage), causing plant death and thinning of crops. Larvae feed on roots, weakening plants (Akhatov et al., 2013).

Life cycle: Beetles overwinter in the soil at a depth of 15–30 cm. In spring, they emerge to the surface and fly to beet seedlings. Eggs are laid in the soil near plant roots.

Control measures: Agronomic measures (deep plowing, weed control) and insecticide treatments of crops during the mass emergence of beetles.

4.4. Beet Cyst Nematode (Heterodera schachtii)

This is a microscopic worm that is one of the most specific and dangerous pests of beet. Although it cannot be seen with the naked eye, the damage it causes is colossal.

How to recognize: Externally, infested plants are severely stunted, leaves become smaller, and plants look depressed (Akhatov et al., 2013). A characteristic "beard" of many small lateral roots forms on the roots (Akhatov et al., 2013; Rana, 2018). This is a result of the toxic effect of the nematode, which disrupts the plant's vascular system. If such a plant is dug up, tiny white or dark brown lemon-shaped formations can be seen on these small roots — these are female nematodes (cysts) (Akhatov et al., 2013). One cyst can contain up to several hundred eggs.

Life cycle: Several generations develop during the growing season (up to 4–5 in southern regions). Eggs overwinter in cysts, which can remain viable in the soil for up to 9 years (Akhatov et al., 2013; Rana, 2018).

Control measures:

• Crop rotation: The most effective method. Beet can be returned to an infested field no earlier than after 4–5 years (ideally 7–9 years), using cereals, corn, alfalfa, potatoes in rotation (Akhatov et al., 2013). This is a "starvation diet" for the nematode.
• Weed control: Destroy weeds from the Chenopodiaceae (lamb's quarters, goosefoot) and Brassicaceae (wild radish, shepherd's purse) families, which are nematode reservoirs (Akhatov et al., 2013).
• Chemical method: On industrial plantations, seed treatment and soil application of nematicides are used (Akhatov et al., 2013). In private plots, this is practically unavailable, so the main focus is on crop rotation and weed control.
• Biological method: Planting marigolds as green manure or in inter-rows can reduce nematode populations (Rana, 2018).

Main takeaway for soil pests: Controlling them is much more difficult than leaf pests. Your best ally is proper agronomy. Deep autumn digging, crop rotation, and weed control are measures that create unfavorable conditions for the development and reproduction of underground pests, allowing you to preserve the harvest without aggressive chemicals.

Great, let's continue. If damage to leaves or roots is always a serious problem, then damage to the growing point is a catastrophe for the plant. The growing point (beet heart) is the generative center from which new leaves develop. Its loss means the plant cannot form full tops, and consequently, a root crop. In this chapter, we will discuss the most dangerous pests that attack this vulnerable zone.

5.1. Beet Moth (Scrobipalpa ocellatella)

This pest is a real scourge for beet in many regions of the world, including Europe, North Africa, and Asia (Ulatowska et al., 2025). It is also called a "hidden-living" pest because it is difficult to detect at early stages.

How to recognize: Caterpillars of the beet moth are grey-green, with a brown head, up to 12 mm long (Akhatov et al., 2013; Ulatowska et al., 2025). On their back, five broken pinkish stripes are clearly visible (Ulatowska et al., 2025). The adult moth is small (wingspan 12-15 mm), greyish-brown, with black spots on the wings (Ulatowska et al., 2025).

Nature of damage: Young caterpillars first mine leaves, but the greatest danger is that they climb into the heart — between the young leaves in the center of the rosette (Ulatowska et al., 2025). There, they web them together with silk and eat the tender tissues. Damaged "hearts" turn black, rot, and the plant stops developing (Ulatowska et al., 2025). Caterpillars also gnaw tunnels in petioles and can even bore into the upper part of the root (Akhatov et al., 2013).

Why this is so dangerous:

1. Loss of the growing point: If caterpillars destroy the central bud, the plant can no longer produce new leaves. It will only survive on old leaves, which will gradually die off.

2. Development of rots: Damage and caterpillar excrement create an ideal environment for the development of fungal and bacterial infections, such as Phoma betae, Botrytis cinerea, and others (Ulatowska et al., 2025). Rot from the heart quickly spreads to the root crop, making it unsuitable for storage.

3. Yield reduction: Losses can be colossal. Studies show that even with damage to 20-25% of plants, yield decreases by 2.3-3.8 t/ha, and sugar content drops (Ulatowska et al., 2025). In some cases, yield and sugar losses can reach 50% (Ulatowska et al., 2025).

Life cycle: This is a polyvoltine species, producing 3-4 or more generations per season (Ulatowska et al., 2025). It overwinters as a caterpillar or pupa in the soil or on plant debris (Akhatov et al., 2013). The first flight of moths begins in spring, and generations overlap, so by late summer all developmental stages can be found in the field simultaneously.

Control measures:

• Monitoring: Use pheromone traps to track moth flights. This allows determination of optimal treatment times (Ulatowska et al., 2025).
• Agronomy: Deep autumn plowing or digging to destroy overwintering stages. Destruction of plant debris. Crop rotation.
• Chemical method: Insecticide treatments should be carried out during the period of mass moth flight and larval hatching, before they penetrate the heart. Important: caterpillars inside the growing point are protected by silk, so for effective control, systemic products should be used, or treatments should be carried out with a large volume of working solution (400-600 L/ha) to reach the most hidden places (Ulatowska et al., 2025).

5.2. Beet Leaf Miner Fly (Pegomya spp.)

Although the pest was described in Chapter 2, it is important to emphasize its danger to the growing point, especially for young plants.

Nature of damage: Fly larvae mine leaves, but on young plants at the 2-3 true leaf stage, they often damage the central leaf and the growing point, leading to plant death (Akhatov et al., 2013). The larva penetrates the petiole or base of the central leaf, eating tissues and causing its death.

Control measures: Same as in Chapter 2. It is especially important to protect young seedlings during the fly flight period (late May — early June) (Akhatov et al., 2013).

5.3. Beet Weevil (Bothynoderes punctiventris)

Adult beetles of this pest are especially dangerous during the emergence of seedlings.

Nature of damage: Beetles eat cotyledons and young leaves, but can also damage the growing point, completely destroying it (Akhatov et al., 2013). This leads to plant death. The weevil is especially dangerous in hot, dry springs when beetle activity is maximal (Akhatov et al., 2013).

Control measures: Insecticide treatment of crops during the mass emergence of beetles in spring. Agronomic measures: deep plowing and weed control.

5.4. Other Chewing Pests

Cutworm caterpillars (e.g., turnip moth) can also cause irreparable damage. Young caterpillars feed on leaves, but older caterpillars can gnaw through stems at ground level, damaging the base of the growing point as well (Akhatov et al., 2013).

Mole cricket can gnaw through the stems of young plants at the very base, also leading to the death of the growing point.

Practical recommendations for protecting the growing point:

1. Regular inspection: Especially carefully inspect the center of the rosette (heart) for the presence of silk, excrement, or blackened leaves.

2. Systemic products: To protect hard-to-reach areas such as the growing point, prefer systemic insecticides that penetrate plant tissues and kill pests from the inside.

3. Treatment timing: The most effective time for control is during the period of mass moth flight and larval hatching (for moth) or during the period of active beetle feeding (for weevil). Treatments carried out after the pest has already penetrated the heart may be ineffective.

4. Increased spray volume: When treating against beet moth, it is recommended to use large volumes of working solution (400-600 L/ha) to ensure penetration of the product deep into the rosette.

Important: If you find that the growing point is already damaged, the chances of saving the plant are slim. In this case, it is better to remove it from the bed so it does not serve as a source of infection for neighboring healthy plants, and focus on protecting the remaining ones (Ulatowska et al., 2025). Remember: in the fight for the heart, victory is decided in the first days and even hours after the pest appears.

6.1. Economic Thresholds for Major Beet Pests

ETH depends on many factors: plant development stage, region, weather conditions, and even the cost of insecticides. Different countries and regions have established their own threshold values (Ulatowska et al., 2025). Here are approximate figures for the main pests:

Beet Moth (Scrobipalpa ocellatella):

• This pest is dangerous at all stages, but the critical period is root formation.
• Stage 6-8 true leaves: At an average density of 1 caterpillar per 2 plants, control is already required (Akhatov et al., 2013).
• Beginning of root formation: The threshold drops to 1 caterpillar per plant (Akhatov et al., 2013).
• Beginning of leaf die-off: Up to 2 caterpillars per plant is acceptable (Akhatov et al., 2013).
• In different European countries, thresholds vary: in Hungary — 1-5 caterpillars/plant, in Ukraine — 3-6, in Slovenia — 4-5 caterpillars on 50-70% of plants (Ulatowska et al., 2025).
• For pheromone traps: In Poland, it is considered that treatment should be carried out about a month after the first mass capture of moths (Ulatowska et al., 2025). Exact catch numbers are not given, but this shows that monitoring with traps is an important forecasting tool.

Beet Flea Beetle (Chaetocnema concinna):

At the seedling stage ("fork"), a density of 3-5 beetles per 1 m² is considered critical (Akhatov et al., 2013). At such density, flea beetles can destroy seedlings in 2-3 days, especially in hot, dry weather.

Beet Leaf Miner Fly (Pegomya spp.):

There is no clear universal threshold, but a decision to treat is made when mass egg-laying and the beginning of larval hatching are detected, especially on young plants. If more than 10-15 mines are found on a plant, this is already a serious signal.

Aphids (Aphis fabae):

Due to their ability to multiply rapidly and transmit viruses, the decision to treat is made when the first colonies appear, especially on seed crops (Akhatov et al., 2013). Waiting for mass reproduction is not advisable.

Soil Pests (Wireworms, Mole Cricket):

It is difficult to establish a precise ETH for them, as they live in the soil and are difficult to count. The decision to treat is based on the field's history (whether there have been problems before) and the results of digging or bait crops. For example, for the beet cyst nematode, the damage threshold is 5-7 cysts per 100 cm³ of soil (Akhatov et al., 2013).

6.2. How to Apply This Knowledge in Practice?

For gardeners and small farmers, this means the following:

1. Regular monitoring is your main tool. Walk your beds at least 1-2 times a week. Inspect not only the upper side of leaves but also the lower side and the center of the rosette (heart). Each growth phase has its own "critical windows."

2. Count. You don't need to count every aphid, but try to assess the scale: how many plants are damaged? What is the intensity of damage? For example, if you see 2-3 moth caterpillars on every third plant, and the roots are starting to swell — it's time to act.

3. Consider the plant's development stage. Young seedlings are more vulnerable, and the threshold for them is lower. An adult plant with strong tops can withstand a larger number of pests without serious losses.

4. Consider the weather. In hot and dry weather, the harmfulness of many pests (flea beetle, aphids, moth) increases as they reproduce faster and plants are weakened. In such weather, threshold values should be taken more strictly.

5. Don't forget about natural enemies. If you see ladybirds, lacewings, or hoverflies on the leaves, that is a good sign. They can keep aphid and other pest populations in check. By using chemicals, you kill them too, so chemical treatments should be used only when biological control is failing.

6.3. What to Do If the Threshold Is Exceeded?

If you find that the pest population exceeds the ETH, follow this algorithm:

1. Choose the right product. For chewing pests on the surface (flea beetle, caterpillars), contact and stomach insecticides are suitable. For hidden-living pests (moth in the heart, leaf miner), systemic products that penetrate plant tissues are needed.

2. Observe waiting periods. Always read the product label. Follow the pre-harvest interval. This is important for your safety.

3. Rotate products. Do not use the same product constantly to avoid developing resistance in pests.

4. Treat at the right time. For controlling moth, it is critical to carry out treatments before caterpillars get into the heart. For flea beetle — at the seedling stage. For aphids — when the first colonies appear.

Main takeaway: The economic threshold is not just an abstract number, but your main assistant in decision-making. It helps you act rationally, saving time, money, and protecting the environment. Remember that the goal is not to destroy every single pest, but to prevent their mass reproduction and preserve the harvest.