Pests

Cruciferous Flea Beetle (Phyllotreta spp.)

The most dangerous and widespread pest of young cabbage plants in most regions of the world. These are small (2–3 mm) jumping beetles with a metallic sheen—black, green, blue, or with yellow stripes on the elytra (Akhatov et al., 2013; Startsev, 2021).

How to know it's them. Numerous small, round holes or pits appear on the leaves—a "punctuated" or "net-like" surface, as if the leaf was shot with fine shot (Teverson, 2020). In severe infestations, the leaves become riddled with holes, with visible perforations 1–3 mm in size (Fig. 2.1). In hot, dry weather, flea beetles are particularly active—they can destroy seedlings within 1–2 days. Damage to the growing point at the seedling stage causes the plant to produce several small, unmarketable heads instead of one large one (Startsev, 2021).

When to expect them. Flea beetles emerge from overwintering in early spring, as soon as the soil thaws. Initially, they feed on weeds in the Brassicaceae family (shepherd's purse, field mustard, wild radish), then move to cultivated plants. Peak activity occurs on hot, sunny days from 10:00 AM to 1:00 PM and from 4:00 PM to 6:00 PM (Akhatov et al., 2013).

What to do. The main principle is to accelerate plant growth and development. The faster seedlings establish and strengthen, the easier they will tolerate damage:

• Floating row cover — the most reliable protection method in the first 1–2 weeks after planting. It allows light and water through but creates a physical barrier against beetles (Kemble, 2022).
• Regular watering — flea beetles prefer dry conditions, so maintaining soil moisture reduces their activity (Teverson, 2020).
• Dusting — with a mixture of wood ash and tobacco dust (1:1) or dry mustard powder. This works as a repellent, but the effect is short-lived, especially after rain (Startsev, 2021). Ash also serves as a potassium fertilizer, strengthening plant tissues.
• Timely weed removal — eliminates the primary food plants for the beetles (Akhatov et al., 2013).

On large areas with massive infestations, approved insecticides are used, but for amateur gardeners, preventive and mechanical methods are primarily recommended.

Cabbage Root Fly (Spring) — Delia brassicae

This pest resembles a common house fly (6–6.5 mm) in appearance, being gray in color, and is dangerous not as an adult, but as larvae. The cabbage root fly is widespread and most damaging in the Non-Chernozem zone and Siberia (Akhatov et al., 2013; Startsev, 2021).

How to know it's them. Symptoms don't appear immediately. The plant begins to wilt in hot weather, although it may look normal in the morning. Leaves take on a bluish tint, and growth slows. Upon inspecting the root collar, damage can be seen—brown, rotting areas at the base of the stem, and tunnels inside the stem (Teverson, 2020). If you tug the plant, it pulls out of the soil easily, and white, legless larvae up to 8 mm long are visible on the roots (Fig. 2.2).

When to expect them. The mass flight of flies coincides with cherry blossom (late April–May in the central zone), and mass egg-laying coincides with lilac blossom. This is an excellent phenological signal for gardeners: when lilacs bloom, it's time to take action (Akhatov et al., 2013). Females lay eggs (2–3 at a time) on the root collar or in the soil next to the plant. They prefer more developed plants, rarely attacking young seedlings with less than three leaves.

What to do. The main strategy is to create conditions where the plant can grow additional roots:

• Hilling up — promotes the formation of an additional tier of roots above the damage site. Hill up with moist soil, combining with watering and feeding (Startsev, 2021). This is the most reliable agrotechnical method.
• Planting at the optimal depth — planting too deep increases plant losses, while normal planting (up to the cotyledon leaves) promotes rapid rooting.
• Floating row cover — creates a physical barrier, preventing flies from laying eggs at the base of the stem (Kemble, 2022).
• Crop rotation — larvae overwinter in the soil as pupae, so cabbage can only be returned to the same site after 3–4 years (Teverson, 2020).

For small plantings, using root collars made of thick paper or roofing felt placed around the stem is effective—they physically hinder egg-laying.

Summer Cabbage Root Fly (Delia floralis)

Similar in appearance to the spring fly but larger (7–8 mm). Found mainly in the Non-Chernozem belt and northern regions, on peaty and old garden soils. Produces one generation per year, with fly flight occurring in late June (Startsev, 2021). Larvae of the summer fly also damage roots and the stem base but penetrate deeper compared to the spring fly. Control measures are the same as for the spring fly, but treatment times are shifted to July (Akhatov et al., 2013).

Cutworm Caterpillars (Noctuidae)

This group includes caterpillars of the cabbage moth (Mamestra brassicae), the garden dart, and the silver Y moth. These are thick, almost hairless caterpillars up to 50 mm long, with coloration varying from green to dark brown and almost black (Akhatov et al., 2013; Startsev, 2021).

How to know it's them. On young plants, caterpillars cut the stem at ground level, often completely severing it. The plant falls over as if cut down. On leaves, large, ragged holes are noticeable, especially on the lower part, or the leaf is eaten from the edges (Teverson, 2020). On heads, there are through tunnels and frass. Caterpillars are active at night and in overcast weather; during the day, they hide under plant debris or in the topsoil (Fig. 2.3).

When to expect them. Moths begin flying in early summer, laying eggs on the underside of leaves. Caterpillars of the first generation are damaging in July, and the second in August–September. Caterpillars of older instars are most dangerous, capable of penetrating inside the head and contaminating it with frass (Akhatov et al., 2013).

What to do:

• Autumn and spring digging of the soil — destroys overwintering pupae.
• Hand collection — cutworm caterpillars are collected in the evening hours when they come out to feed. During the day, they can be found under clods of earth or in the root zone (Startsev, 2021).
• Biopesticides — based on Bacillus thuringiensis (Bitoxibacillin, Lepidocide) are effective against younger caterpillars while they still feed openly and haven't penetrated the head (Teverson, 2020).
• Attracting entomophages — Trichogramma, Apanteles (parasitic wasps) effectively reduce populations of cutworms and whites. They are attracted by nectar-bearing plants (dill, phacelia, flowers) (Startsev, 2021).

Mole Cricket (Gryllotalpa gryllotalpa) — "Cabbage Cricket"

A large insect (up to 50–60 mm) with powerful digging forelegs. It damages not only cabbage but also many other vegetable crops. Prefers moist, well-manured soils, especially on old garden plots (Akhatov et al., 2013; Startsev, 2021).

How to know it's them. Plants suddenly wilt, sometimes the day after planting, without visible damage to the above-ground parts. When pulling the plant, the roots are found to be gnawed off at the very base. Horizontal tunnels 1–2 cm in diameter are visible in the soil (Fig. 2.4). The mole cricket gnaws roots and stems at soil level and destroys sown seeds (Akhatov et al., 2013).

When to expect them. The mole cricket is active throughout the warm season but causes the most damage in spring—after emerging from hibernation when especially hungry. Nests are built up to 15 cm deep in the soil, where eggs are laid (Startsev, 2021).

What to do. Mole crickets are difficult to destroy with one-off measures; a systematic approach is needed:

• Trapping pits and baits — in autumn, dig trenches up to 50 cm deep on the plot and fill them with fresh manure. When cold weather sets in, dig up the baits and destroy the mole crickets that have gathered there. In spring, lay out baits of boiled grain mixed with sunflower oil and bury them 2–3 cm deep (Startsev, 2021).
• Repellents — alder branches stuck in the ground at 1.5 m intervals (the smell repels mole crickets), as well as trenches with sand soaked in kerosene around the perimeter of the beds (Akhatov et al., 2013).
• Effectiveness of baits — using baits is especially effective in August–September, when young mole cricket nymphs are most hungry.

Slugs (Agriolimax, Deroceras and others)

Slugs cause the most damage in rainy and overcast years. They are active at night and in damp weather, hiding during the day under clods of earth, boards, and plant debris (Akhatov et al., 2013; Startsev, 2021).

How to know it's them. A characteristic sign is eaten leaf edges with irregular, ragged margins and the presence of a silvery mucous trail (Fig. 2.5). Young plants can be eaten entirely, including the growing point. On heads — deep ulcers and through holes. Slugs often damage inner leaves by crawling inside the head (Teverson, 2020). In sunny weather, searching for them is futile — they hide under cover, emerging to feed at dusk.

When to expect them. Slugs are particularly dangerous for seedlings soon after planting. Peak activity occurs on warm, humid nights with temperatures of 15–20°C. In dry weather, their numbers decrease.

What to do:

• Maintaining plot cleanliness — removing weeds, debris, boards, and stones where slugs accumulate (Startsev, 2021).
• Hand collection — in the evening or early morning using traps: place pieces of plywood, dark film on the plot, under which slugs gather (especially effective with a damp surface) (Akhatov et al., 2013).
• Barrier defenses — strips of hydrated lime, superphosphate, ash, or tobacco dust around the beds. Slugs dislike crossing such strips.
• Baits — based on iron phosphate (safe for humans and pets) or, as a last resort, metaldehyde (use with caution, only on small areas, and not later than 20 days before harvest) (Kemble, 2022).
• Regular loosening — destroys slug egg clutches in the topsoil.

Large White Butterfly (Pieris brassicae) — "Cabbage White"

A large diurnal butterfly with white wings, reaching a wingspan of 50–63 mm. In the central zone, it produces 2 generations per year, in the south — up to 3–4 (Akhatov et al., 2013; Startsev, 2021).

How to know it's them. Cabbage white caterpillars are yellowish-green, with black dots and yellow stripes on the sides, up to 40 mm long. The body is covered with bristles and hairs. The most characteristic sign is that they skeletonize leaves, eating all the flesh between the veins, leaving only a "skeleton" of thick veins (Fig. 3.1). Caterpillars stay in groups, especially in younger instars, and can completely destroy a head at the folding stage within 2–3 days (Teverson, 2020; Startsev, 2021). Their frass, in the form of dark balls, is easily visible on the leaf surface.

Cabbage white caterpillars usually don't penetrate inside the head but eat the wrapper leaves, leaving thick veins. In severe infestations, the head may completely lose its marketable appearance, although inner leaves remain undamaged (Akhatov et al., 2013).

When to expect them. Butterflies appear in May and lay eggs in clusters of 15–200 on the underside of leaves. Caterpillars emerge in 8–12 days. The greatest damage is caused by caterpillars of the second and third generations in July–August. In hot years in the south, three generations may develop (Startsev, 2021).

Small White Butterfly (Pieris rapae) — "Small White"

A small white butterfly, very similar to the large white but smaller (wingspan 40–50 mm) (Akhatov et al., 2013).

How to know it's them. Small white caterpillars are velvety green, without hairs, up to 25 mm long. Unlike the large white, they occur singly. The damage differs: the small white eats the leaf tissue, leaving only the upper epidermis intact, resulting in "windows" — thin, translucent areas (Startsev, 2021; Teverson, 2020). Older caterpillars eat the leaves entirely but leave some tissue near the veins, unlike the large white (Fig. 3.2).

A peculiarity of the small white is that it often penetrates inside the head, bores tunnels, and contaminates it with frass, making the produce unsuitable for sale (Startsev, 2021). This is a key difference from the large white.

When to expect them. The small white develops in 2–3 generations, with the third often incomplete. The greatest damage occurs in July–August (Akhatov et al., 2013).

Diamondback Moth (Plutella xylostella)

One of the most dangerous caterpillars for cabbage, especially in the south. In recent decades, it has gained status as a serious pest worldwide due to rapid resistance development to insecticides (Teverson, 2020; Kemble, 2022).

How to know it's them. Diamondback moth caterpillars are very small — up to 10–12 mm, greenish, and mobile. When touched, they wriggle and often drop from the leaf on a silk thread (Akhatov et al., 2013). The first sign of their presence is "mines" (tunnels) inside the leaf, which the caterpillar eats without damaging the upper epidermis (Fig. 3.3). Later, caterpillars come to the surface and eat the leaf, leaving only the upper epidermis (Startsev, 2021). Damage appears as light, elongated stripes — "windows" or "scab".

During mass outbreaks, diamondback moth caterpillars can completely destroy the leaf apparatus, leaving only veins and a thin film of epidermis. Seedlings and young plants suffer especially severely (Teverson, 2020).

When to expect them. Butterflies appear in spring and lay eggs on the underside of leaves. In warm weather, a generation develops in just 2–3 weeks, so up to 4–6 generations can occur per season (Akhatov et al., 2013).

Cabbage Moth (Mamestra brassicae) and Other Cutworms

We mentioned cutworm caterpillars in the section on seedlings, but they are equally dangerous on mature plants.

How to know it's them. Older cutworm caterpillars (up to 50 mm long) make deep, through tunnels in heads, gnawing holes up to 1 cm in diameter and contaminating inner leaves with frass (Fig. 3.4). Unlike whites, cutworm caterpillars are nocturnal; during the day, they can be found at the base of the stem or inside the head (Akhatov et al., 2013; Startsev, 2021).

When to expect them. Moths begin flying in June; caterpillars are active in the second half of summer. They are most dangerous for cabbage just before harvest, when they enter the head (Startsev, 2021).

Cabbage Webworm

Occurs less frequently, but in some years, it can cause significant damage. Webworm caterpillars first eat the flesh of leaves from the underside, making "windows," then gnaw through holes and can enter the head, damaging inner leaves (Startsev, 2021).

Cabbage Aphid (Brevicoryne brassicae)

The most widespread sucking pest of cabbage. These are small (1.8–2.3 mm) grey-green insects covered with a white waxy secretion, making colonies look like grey dust (Akhatov et al., 2013).

How to know it's them. Aphids form dense colonies on the underside of leaves and on young shoots. Leaves curl, discolour, sometimes develop a reddish (anthocyanin) tint, and drop prematurely (Teverson, 2020). A sticky, sweet liquid (honeydew) appears on the leaf surface, on which a black sooty mold later develops. This is one of the most characteristic signs of aphid infestation (Fig. 3.5). In severe cases, head development stops (Startsev, 2021).

When to expect them. Cabbage becomes colonized by aphids in mid-summer (in the central zone — in the second half of July). The pest reproduces parthenogenetically — without fertilization — ensuring explosive population growth. Up to 10–15 generations occur during the summer (Akhatov et al., 2013).

What to do. Aphids are one of the few pests against which biological methods are truly effective:

• Attracting entomophages — parasitic wasps (e.g., Diaeretiella rapae) and predators (lacewings, hoverflies, ladybugs) can destroy up to 80–90% of aphids (Startsev, 2021).
• Biopesticides — based on Bacillus thuringiensis and other entomopathogens, as well as soap solutions and plant extracts.
• Gentle insecticides — products with a short pre-harvest interval (e.g., based on pyrethrins) that are less toxic to beneficial insects are preferable. Important: treatments should be carried out when aphids are just beginning to colonize plants, not waiting for dense colonies to form (Teverson, 2020).

Onion Thrips (Thrips tabaci) and Other Species

Small (up to 2 mm) insects with fringed wings. They damage not only cabbage but also many other crops (onion, cucumber, pepper) (Akhatov et al., 2013).

How to know it's them. Small, light spots or streaks appear on leaves — places where thrips have sucked out sap. Damaged areas eventually turn brown, and the leaf takes on a mosaic yellowish-brown appearance (Fig. 3.6). In severe infestations, leaves completely discolour and dry up. A characteristic sign is many small, dark dots of frass on the leaf surface (Teverson, 2020). Thrips often hide between the leaves of the head, especially under the 5th-6th layer, making them difficult to reach with sprays (Startsev, 2021).

When to expect them. In open ground, they are active in dry, hot weather. They often migrate from neighbouring onion fields or other crops, which should be considered when planning plantings (Akhatov et al., 2013).

Green Peach Aphid (Myzus persicae)

A yellowish-green aphid without a waxy coating. Its danger lies not so much in direct damage but in being a vector for over 100 viruses, including turnip mosaic virus and cauliflower mosaic virus (Akhatov et al., 2013; Teverson, 2020). It causes the most damage during the seedling stage in greenhouses. Damaged leaves turn yellow, buds drop, and plants lag in growth (Startsev, 2021).

Cabbage Stem Weevil (Ceuthorrhynchus quadridens)

Although its larvae mine stems, the beetle itself damages leaves, gnawing characteristic pits in petioles and veins. Whitish "windows" appear on the leaf blade at the puncture sites (Startsev, 2021). The larvae bore tunnels through the petiole to the stem, weakening the plant and causing its death.

How to know it's them. Small swellings or pinpoint holes are visible on leaf petioles and the midrib. Inside the petiole — a tunnel made by the larva. In severe infestations, leaves turn yellow and drop prematurely. On cauliflower, larvae can enter the curd (Startsev, 2021).

Monitoring

Visual inspection of plants at least 1–2 times a week is crucial. Pay attention to:

• Presence of egg masses on the underside of leaves (for whites — in clusters; for moths — singly) (Akhatov et al., 2013).
• Initial damage — "windows," mines, tiny spots.
• Presence of frass — for caterpillars, it's in the form of large dark balls; for thrips, it's in the form of small black dots (Teverson, 2020).

Biological Control Agents

• Bacillus thuringiensis (Lepidocide, Bitoxibacillin) — effective against younger caterpillars, especially diamondback moth and whites. Important: apply when caterpillars are still feeding openly and haven't entered the head (Teverson, 2020).
• Soap solutions and plant oils — effective against aphids and thrips, acting by contact.
• Attracting entomophages — sow flowering umbelliferous crops (dill, fennel, parsley, carrot left for seed) near cabbage. They attract parasitic wasps and predatory insects that control aphid and caterpillar numbers (Akhatov et al., 2013).

Mechanical Collection and Destruction

• Crush white butterfly egg masses, preventing caterpillars from pupating (Startsev, 2021).
• Handpick caterpillars in the morning when they are less active.
• Using pheromone traps — helps monitor moth flight and time treatments appropriately (Kemble, 2022).

Floating Row Cover

Dense non-woven material secured on hoops not only protects seedlings but also effectively prevents white butterfly and moth flights, reducing egg-laying on leaves (Kemble, 2022).

In the next chapter: we will move on to root pests — those who quietly undermine the plant from below, causing sudden wilting. This includes the already familiar cabbage root fly, wireworms, and the mole cricket. We'll learn how to diagnose root damage and save your plantings.

Cutworm Caterpillars (Especially Cabbage Moth — Mamestra brassicae)

Cutworms are nocturnal moths whose caterpillars lead a hidden lifestyle. They are the most dangerous for the head because they don't just eat outer leaves but actively penetrate inside (Startsev, 2021).

How to know it's them. Ragged, irregularly shaped holes appear on the outer leaves of the head, sometimes with through tunnels. Inside the head, between leaves, large (up to 3–4 cm), thick caterpillars are found, along with their dark frass — balls resembling poppy seeds but larger (Teverson, 2020). Caterpillars make deep, winding tunnels inside the head, often reaching the core. The tissues in the tunnels darken, soften, and rot bacteria easily penetrate through these injuries. Cutting the head reveals black, rotting areas and tunnels, sometimes filled with frass (Akhatov et al., 2013).

Behavioral features. Cutworm caterpillars are active at night and hide inside the head or in the soil at its base during the day. Thus, they are hard to spot during daytime inspections. They leave large frass on the leaf surface, which can indicate their presence even if you don't see the caterpillars (Startsev, 2021).

When to expect them. Cutworms are most dangerous in late July–August, when caterpillars of the second generation reach older instars and actively seek shelter inside the head to pupate (Akhatov et al., 2013).

Small White Caterpillars (Pieris rapae)

The small white is another pest that, unlike the large white, regularly penetrates inside the head (Startsev, 2021).

How to know it's them. Signs are similar to cutworms: ragged holes on outer leaves, tunnels and dark ball-like frass inside. However, there are differences: small white caterpillars are velvety green and hairless, unlike the grey-green or brown cutworm caterpillars. Also, the small white leaves characteristic "windows" on leaves in early stages before entering the head (Teverson, 2020). Damage by the small white is often more superficial — it reaches the core less frequently — but frass contamination makes the head unmarketable (Akhatov et al., 2013).

When to expect them. Active throughout the summer in several generations; greatest damage in July–August when caterpillars of the second and third generations reach older instars (Startsev, 2021).

Cabbage Webworm Caterpillars (Evergestis forficalis)

This pest is less known but can cause significant damage in some years. Webworm caterpillars initially eat the flesh of leaves from the underside, then penetrate the head, boring tunnels and contaminating leaves with frass (Startsev, 2021).

How to know it's them. The outer leaves of the head have through holes, often with irregular, "torn" edges. Inside the head, brownish caterpillars up to 15–18 mm long are visible; they are active during the day and easier to find than cutworms. A characteristic sign is light webbing on the leaf surface, which the caterpillars use to bind leaves before pupation (Akhatov et al., 2013).

When to expect them. The webworm produces 1–2 generations per year. In the central zone, caterpillars are active in July–August, and they can damage heads even during storage if brought in from the field (Startsev, 2021).

Diamondback Moth Caterpillars (Plutella xylostella) at Late Stages

Young diamondback caterpillars mine leaves and live openly, but older instars (especially in high numbers) can penetrate the head, eating the flesh of inner leaves (Teverson, 2020). Unlike cutworms and the small white, moth caterpillars are small (up to 10–12 mm), so tunnels inside the head are thin, winding, and shallow. However, mass infestations can spoil several inner layers of leaves.

When to expect them. Active throughout the warm season; in hot weather, up to 5–6 generations occur, so the threat persists until harvest (Akhatov et al., 2013).

Slimy Bacterial Rot (Soft Rot)

Caused by the bacterium Pectobacterium carotovorum (formerly Erwinia carotovora). It enters the head through injuries inflicted by caterpillars, slugs, as well as frost damage and mechanical injuries during harvest (Akhatov et al., 2013).

How to know it's them. Affected tissues soften, become slimy, turn cream or light grey, and emit an unpleasant putrid smell (Startsev, 2021). The head may look normal externally, but when cut, inner leaves are completely rotten. Sometimes the process starts from the core, where bacteria enter from the soil through damaged roots (Teverson, 2020). Infection spreads rapidly in conditions of high humidity and temperature.

Which pests contribute. Any that bore tunnels in the head, but especially cutworms and the small white, as they leave large wound surfaces. Also, slug damage creates ideal entry points for bacteria (Akhatov et al., 2013).

Grey Mold (Botrytis cinerea)

A fungal disease developing mainly during storage, but the primary infection often occurs in the field on damaged leaves (Startsev, 2021). The fungus enters through mechanical damage left by pests, as well as frostbitten areas.

How to know it's them. Affected areas become covered with a grey, fluffy coating — fungal sporulation. Later, black sclerotia (fungal resting bodies) form on the tissues — they are clearly visible on the head's surface (Teverson, 2020). The rot develops in storage at high humidity, but the initial focus is on leaves damaged by pests.

White Mold (Sclerotinia sclerotiorum)

A fungus that infects heads, especially in rainy years, through injuries caused by pests (Akhatov et al., 2013). A white, cottony coating (mycelium) appears on the head's surface, followed by large black sclerotia up to 1–3 cm in size. The affected head quickly becomes slimy and rots (Startsev, 2021).

General rule. Pest damage always entails a risk of rot development, which can destroy the entire harvest during storage. Therefore, controlling head pests is not only about preventing mechanical damage but also about preventing storage diseases.

Monitoring and Hand Collection

• Regularly (every 3–4 days) inspect heads for entry holes and frass on the surface.
• If caterpillars are found inside, they can be removed manually by cutting out the damaged area. If severely damaged, remove the head from the bed and destroy it (Akhatov et al., 2013).
• Collect slugs using traps (boards, dark film) in the evening or early morning.

Biological Control Agents

• Bacillus thuringiensis (Lepidocide, Bitoxibacillin) is effective against younger caterpillars while they are still feeding openly and haven't entered the head. On older caterpillars already inside, the product is less effective because the bacteria must enter the insect's gut, and caterpillars inside the head feed hidden (Teverson, 2020). Therefore, it's crucial to apply treatments at the time of mass caterpillar emergence, before they enter the head.
• Spinosad — a biopesticide based on products from the bacterium Saccharopolyspora spinosa, effective against older caterpillars, including cutworms, and has translaminar activity (penetrates leaf tissue) (Kemble, 2022).
• For slugs, use baits based on iron phosphate (safe for humans and pets) or metaldehyde (use with caution, no later than 20 days before harvest) (Kemble, 2022).

Attracting Entomophages

Parasitic wasps (Trichogramma, Apanteles) effectively reduce the number of white and cutworm eggs and young caterpillars. To attract them, sow flowering umbelliferous crops (dill, fennel, parsley left for seed) near the cabbage (Akhatov et al., 2013; Startsev, 2021).

Timely Harvesting

• Don't leave cabbage in the field after heads reach marketable maturity. Overripe heads are more vulnerable to pest penetration (Teverson, 2020).
• During harvest, discard heads with signs of damage — they won't store well and can infect neighboring ones.
• Remove stems and plant debris from the field and destroy them — this eliminates overwintering caterpillars and pupae (Startsev, 2021).

Proper Storage

Before storing, heads must be clean, dry, and undamaged. Even a small injury left by a caterpillar can become a focus of grey or white mold in storage (Teverson, 2020; Startsev, 2021). Optimal storage conditions: temperature 0–1°C, humidity 90–95%, good ventilation. Regularly check the storage and remove rotten heads.

In the next chapter: the most practical block — how to quickly identify a pest by the type of damage without resorting to laboratory diagnostics. We'll compile all signs into a unified system so the gardener can act immediately.

Leaf Damage

Root and Root Collar Damage

Stem, Petiole, and Head Damage

Stage 1. Before Planting: Prevention

The best way to control pests is to prevent their mass development. The main work begins even before seeds hit the soil.

Cabbage cannot be planted in the same place more often than once every 3–4 years. This applies not only to cabbage itself but also to all Brassicaceae family plants (Brassicaceae) — radish, turnip, daikon, swede, mustard, rapeseed (Teverson, 2020; Startsev, 2021).

Why it works. Most cabbage pests (root fly, nematodes, clubroot pathogen) overwinter in the soil and accumulate with continuous cultivation. Short rotation interrupts their life cycle: larvae emerging from pupae in spring find no host plant and die (Akhatov et al., 2013).

Best predecessors for cabbage: legumes (peas, beans), potatoes, tomatoes, onions, cucumber, green manures. Avoid planting after other Brassicas, as well as after beet and carrot, which share common pests (e.g., beet cyst nematode) (Tarakánov and Mukhin, 2003).

• Autumn deep digging (plowing) to a depth of 20–25 cm destroys overwintering sites of root fly pupae, wireworm larvae, and mole crickets, and brings overwintering stages to the surface where they die from frost (Akhatov et al., 2013).
• Liming acidic soils — apply dolomite flour or hydrated lime if pH is below 6.0. This reduces the numbers of wireworms, nematodes, and the clubroot pathogen (Startsev, 2021).
• Removing plant debris — remove stems and leaves from the previous crop from the site or deeply incorporate them into the soil. They may harbor pupae and eggs of pests (Teverson, 2020).

When choosing seeds, look for resistance markers:

• Clubroot — there are hybrids with genetic resistance to clubroot (e.g., Kilaherb, Kilaton, Tequila from Syngenta) (Akhatov et al., 2013).
• Nematodes — marked with the letter N (e.g., F1 N).
• Fusarium wilt — marked with the letter F (Startsev, 2021).
• Cabbage aphid, thrips — some hybrids have tolerance (less attractive to pests).

Using resistant varieties is the most environmentally friendly and cost-free method for the gardener (Kemble, 2022).

Hot water (48–50°C, 20 minutes) destroys pathogens of bacteriosis and fungal diseases transmitted by seeds. After heating, cool seeds in cold water for 2–3 minutes and dry (Teverson, 2020). This reduces the risk of early seedling diseases that weaken plants and make them more vulnerable to pests.

Stage 2. Sowing and Growing Seedlings: Protection from the Start

Young plants are most vulnerable to a whole range of pests. Protection begins from the moment seeds are sown for seedlings.

Use fresh, purchased potting mix (or steam your garden soil). Containers (trays, pots, boxes) must be clean — wash and scald with boiling water. This prevents seedlings from being infected by soil-dwelling pests and blackleg pathogens (Teverson, 2020; Startsev, 2021).

• Temperature — 18–22°C during the day, not below 12–15°C at night. Avoid cold stress (temperatures below 8–10°C for several days can trigger bolting and make plants more vulnerable) (Tarakánov and Mukhin, 2003).
• Watering — in the morning, so the soil surface dries by evening. This reduces the risk of fungal diseases and attracting sciarid gnats.
• Hardening — 7–10 days before planting in open ground, reduce watering and expose seedlings to fresh air (start with a few hours, gradually increasing time). Hardened plants have denser tissues, making them less attractive to sap-sucking pests (Kemble, 2022).

Before planting, seedlings can be treated with a biopesticide based on Bacillus thuringiensis (Lepidocide, Bitoxibacillin) or Trichoderma — this reduces the risk of infection in the first days after planting (Teverson, 2020).

Stage 3. Planting in Open Ground and the First Month

In the first 2–3 weeks after planting, seedlings are particularly vulnerable to cruciferous flea beetles, cabbage root fly, and mole crickets. This period requires maximum attention.

Non-woven row cover (agrofabric, spunbond, density 17–30 g/m²) on hoops protects against several threats at once:

• Cruciferous flea beetle — physical barrier for beetles.
• Cabbage root fly — flies cannot lay eggs at the stem base.
• White butterflies — cannot lay eggs on leaves.
• Slugs — partially (hinders access).
• Frost and overheating — creates a favorable microclimate for rooting (Kemble, 2022).

How to use. Place row cover immediately after planting seedlings on hoops (so it doesn't touch the leaves) and leave for 2–3 weeks. Once plants are established and growing actively, remove the cover during the day (for pollinator access and sunlight) and replace it at night — or remove completely if pest risk is reduced. For protection against root fly, the cover can be left until head formation, but artificial pollination may be needed (not for cabbage — it's self-pollinating) (Teverson, 2020).

• Regular watering — keep soil moist (not waterlogged). This speeds up establishment and makes plants more resilient to damage.
• Fertilization — 10–14 days after planting, apply a nitrogen fertilizer (nettle or manure tea, or ammonium nitrate — 10–15 g per 10 L water). This stimulates growth of new leaves, helping the plant "outgrow" initial flea beetle damage (Tarakánov and Mukhin, 2003).
• Hilling — 2–3 weeks after planting, hill up plants with moist soil. This stimulates additional root formation and protects against cabbage root fly (Startsev, 2021).

In the first month, inspect plants every 2–3 days. Pay attention to:

• Appearance of small holes on leaves (flea beetle).
• Wilting (root fly, mole cricket).
• Egg masses on the underside of leaves (whites).

Act immediately at the first signs — pests are easier to control at early stages.

Stage 4. Active Growth and Head Formation (July – August)

At this stage, the main threats are leaf-chewing caterpillars (whites, diamondback moth, cutworms), aphids, thrips, and slugs.

• Inspect underside of leaves — every 3–4 days, check for egg masses. White butterfly eggs (yellow, in clusters) — crush them on the spot to prevent hundreds of caterpillars (Akhatov et al., 2013).
• Handpick caterpillars — if caterpillars appear, collect them manually (with gloves) in the morning when they are less active. Destroy them (in a bucket of soapy water or by burning) (Startsev, 2021).
• Inspect plant bases — if you notice slime trails or wilting, check the root zone for slugs and fly larvae.

• Against caterpillars — Bacillus thuringiensis (Lepidocide, Bitoxibacillin). Spray at the time of mass caterpillar emergence (when they are still small and feeding openly). Important: the product works only if ingested by the caterpillar, so spray thoroughly, especially the underside of leaves (Teverson, 2020; Startsev, 2021).
• Against aphids and thrips — soap solutions (40–50 g of laundry soap per 10 L water) or plant oils (e.g., neem oil-based products). They act by contact and are safe for beneficial insects (when applied in the evening) (Kemble, 2022).
• Against slugs — baits based on iron phosphate (safe for humans, pets, and earthworms). Place them in the evening in areas where slugs gather (Startsev, 2021).

• Sow umbelliferous crops near cabbage (dill, fennel, parsley left for seed, as well as phacelia, buckwheat). They attract parasitic wasps (Trichogramma, Apanteles), which lay eggs in white and cutworm eggs and caterpillars, as well as lacewings and hoverflies — natural enemies of aphids (Akhatov et al., 2013; Startsev, 2021).
• Marigolds, calendula, nasturtium — their scent repels whites and aphids. These plants can be planted around the perimeter of cabbage beds (Kemble, 2022).

• Avoid evening watering — damp nights encourage slug activity and fungal disease development, which weaken plants.
• In dry weather, water more frequently to avoid plant stress, which makes them more vulnerable to aphids and thrips (Tarakánov and Mukhin, 2003).

Stage 5. Head Maturation (August – September)

At this time, the main threats are hidden pests inside the head (cutworms, small white, slugs), and the development of secondary rots at injury sites.

• Check heads for entry holes, surface frass, and mucous trails.
• Pay special attention to heads that formed later — they are more vulnerable.
• If entry holes or caterpillars are found inside — take immediate action (see below).

• At this stage, Bacillus thuringiensis is often insufficient — caterpillars inside the head are hard to reach. An alternative is spinosad (a product based on the bacterium Saccharopolyspora spinosa), which has translaminar activity (penetrates leaf tissue) and is effective against older caterpillars (Kemble, 2022). Apply in the evening when cutworm caterpillars become active.
• For slugs, use baits placed at the base of heads, especially in wet weather.

Stop nitrogen fertilization 3–4 weeks before harvest. Excess nitrogen at this stage causes loose heads, more vulnerable to pest entry and rots (Teverson, 2020). Focus on potassium fertilizers — they strengthen head tissues.

If a head is damaged by caterpillars (tunnels, frass found) — it's best to remove it from the bed and use it immediately for processing (e.g., for sauerkraut), not for storage. This prevents rot spread to neighboring heads during storage (Startsev, 2021).

Stage 6. Harvest and Storage

At this stage, the main task is to prevent losses during storage.

• Harvest cabbage in dry weather. Wet heads are more prone to rot.
• Leave 2–3 wrapper leaves — they protect the head from mechanical damage and moisture loss (Startsev, 2021).
• Immediately discard heads with signs of pest damage or rot — they will not store well.

• Before storing, thoroughly clean and disinfect the storage facility (whitewashing, sulfur fumigation) — this kills fungal spores and overwintering pest stages (Teverson, 2020).
• Optimal storage conditions: 0–1°C, humidity 90–95%, good ventilation. In such conditions, pests and rots do not develop (Tarakánov and Mukhin, 2003).

• Every 2–3 weeks, inspect stored cabbage and remove rotting heads. A head damaged by pests often begins to rot from the core or the damage site.