What harm does onion moth cause? Effective ways to combat dangerous insects in the garden

Externally, the onion moth - the photos confirm this - looks completely inconspicuous. This is a butterfly with a dark brown body, the hind wings of which are light gray in color and long fringe, and the front wings are brown with several transverse white stripes and a large white spot at the lower edge of the wing. The body length of this insect pest is 8 mm, and the wingspan is 10...17 mm.

Moths on onion plantings begin to fly in May, and they are more active at night. At this time, butterflies try to lay a single egg on the following parts of the crop:

• on the necks of the bulbs;
• on the lower parts of the bow arrows;
• on flower arrows.

The fertility of each female ranges from 50-75 eggs. The eggs are 0.4 mm long and up to 0.3 mm wide, yellowish, oval in shape, convex on the upper side.

A week after the moth lays eggs on the bulbs, larvae appear. After another 7 days, small (10...11 mm) caterpillars appear from these larvae, yellow-green in color, with brown warts, from which short hairs grow. On the plant, they bite into the leaf pulp, and, making narrow passages, penetrate into the cavity of the shoots or onto the inside of the leaf blades. By damaging the tissues of the leaf plate and peduncles, gnawing the peduncles, the insect leads to the loss of onion seeds.

After one and a half to two weeks, the caterpillars of the moth that settled on the onion plantings crawl out through the leaf blades, move to nearby weeds and equip their cocoons for the next stage of their development. The cocoon, with the pupated caterpillar, has a loose, grayish-web-like structure. The dark brown pupa with a white tip reaches 7 mm in length.

Since the pupal stage lasts only 9-13 days, after which the next generation of pest butterflies fly out of the cocoons, control of onion moths must be carried out with enviable frequency. This usually happens in July and August. In southern regions or during particularly warm summers, three generations of these insects can develop. Butterflies that emerge from their pupae remain for the winter, and in May they will begin their flight.

Appearance Features

These insects from the order Lepidoptera parasitize vegetable crops. Small brown butterflies, decorated with white spots and cross-striations, are found in every vegetable garden. Adults have a pale triangle near the posterior border of the forewings. The bodies of butterflies have an elongated shape, the head and back are brown.

The hind wings of the onion moth are narrow. Their gray or cream color is familiar to most farmers. In the photo of the moth, the long hairs framing the free edge of the hind wings are clearly visible.

Photo of onion moth

Life cycle

Onion moths are sexually dimorphic. Mating of adults occurs from April to September. If the autumn is warm, the process can last until October. In cool climate zones, pests become active later, most often in June or July.

Females lay oval eggs on the back of leaves, necks of bulbs, and inflorescences. These are embryos from which larvae (green caterpillars) later emerge.

Insect development occurs in stages:

1. The appearance of a microscopic egg.
2. Formation of the caterpillar.
3. Insect pupation.
4. A moth emerging from a cocoon.

Attention! In order for the fight against onion moths to be as successful as possible, it is necessary not only to repel the butterflies, but also to destroy the female pests before they begin to lay eggs.

Main Factors

If the onion bed has been properly cared for: watering, fertilizing, loosening, weeding, then all that remains is to look for the reasons for the yellowing of the feather tips in serious problems:

• infectious diseases;
• insect pest activity;
• exposure to changing weather conditions;
• unsuitable soil composition.

Yellowing of the stems in late July or August should not cause alarm. By this time, the bulbs are ripening, and the natural drying of the greenery begins. But the change in feather color in June should be alarming.

To understand the reason for the drying out of the tips of the leaves, you need to dig up a couple of heads and carefully examine them.

Insect larvae and eggs

The transformation from an embryo into an adult butterfly (imago) lasts for onion moths up to 40 days. The female lays more than 90 eggs at a time. They are white or cream in color, length from 0.2 to 0.6 mm. The duration of insect development at this stage is up to 10 days.

The larvae are yellowish-green caterpillars with brown warts and hairs. They damage leaves by gnawing out areas on the inside, destroying buds, and eating stalks. The activity of moth larvae leads to the death of crops. The duration of insect development at this stage is two weeks.

Moth pupae are spindle-shaped and located on the back of the leaf. They develop in about 15 days. Transformations of a growing insect occur not only on the shoots of vegetable plantings, but also on crops growing near the beds.

For your information! To get rid of onion moths at the very beginning of the insect’s development, it is best to use products made from natural ingredients.

Who are these annoying dipterans?

Biological description

A fly is a flying insect with a body length from 2 mm to 2 cm. The body of a fly consists of 3 parts: head, thorax and abdomen.
The insect flies with the help of a pair of membranous wings, and moves along the surface (horizontal, vertical and ceiling) with 3 pairs of legs. This is possible due to the fact that each leg consists of 5 segments, the lower of which (the foot) has 2 claws and a sticky pad.

On the head of the fly there is a proboscis, through which the insect sucks in liquid food, two short olfactory antennae and two large eyes with several thousand hexagonal facets. She has all-round vision, she sees everything that happens not only from the front and sides, but also from behind, and with her antennae she recognizes odors at a great distance.

White, black and miners

There are now such a huge number of varieties of flies (more than 40,000 species) that scientists find it difficult to classify them

But for an ordinary person, it doesn’t matter what species or class a given insect belongs to, but what matters is what it eats and how dangerous it is. Therefore, dipterans are divided into:

• aphagi - adults, do not feed on anything;
• hematophagous - prefer to feed on blood;
• coprophages - in natural conditions they accelerate the process of decay of excrement;
• necrophages - eat dead organic matter;
• nectarophages - the name speaks for itself - plant nectar is eaten;
• polyphagous - they eat everything.

The gardener has his own priorities - he must know which flies are harmful to vegetables and which are beneficial:

1. The enemies of cabbage are 2 types of flies - spring cabbage fly and summer cabbage fly.
2. There are also miners - small insects that lay eggs under the skin of leaves, inside which the larvae then gnaw out passages. However, this variety is polyphagous, appears in late spring - early summer, and prefers cucumbers, salads and tomatoes, so it does not pose a particular danger to cabbage.
3. There is also a useful fly - the hoverfly, which feeds on aphids and sometimes small caterpillars.

Habitat

Vegetable pests specialize in certain vegetables. Cabbage flies often live, reproduce and overwinter in cabbage beds; True, they do not disdain other cruciferous vegetables. These insects can also lay eggs on wild and weedy cruciferous plants.

Appearance

In appearance, cabbage flies are very similar to house flies.

And spring and summer differ in color and size:

• Spring males are dark gray in color with black stripes on the back and reach a size of 5-5.5 mm. Females are light gray in color, slightly larger - 6-6.5 mm. The wings of this variety are transparent with dark gray streaks.
• Individuals of the summer variety reach a length of 7 to 8 mm and have a yellow-gray body and transparent, yellowish wings with yellow veins.

How does it reproduce?

1. The flight of spring dipterans begins at the end of April, and after 2-3 days they mate. After 1-2 weeks, the female lays 100-150 white cigar-shaped eggs measuring 1-1.2 mm on the root collar of the seedling or in the soil next to the cabbage. The full cycle from egg to adult insect takes 40-60 days, and depending on the region, regenerations can range from 1 to 3.
2. Summer (large) cabbage flies mate 7-10 days after emergence. The female also lays from 100 to 150 eggs, but only one generation develops per year. From the eggs, after 5-10 days, depending on the humidity and temperature of the soil, white legless larvae 8 mm long appear.

Danger to cruciferous vegetables

Cabbage flies (spring and summer) are equally harmful to all subspecies and varieties of cabbage, as well as to:

• rutabaga;
• radish;
• radishes;
• turnips

This is due to the fact that it is not the flies themselves that attack the crops, but their larvae, which eat the roots and root crops of the plants. Therefore, it is not so easy to detect them.

At what time of year do plants usually suffer?

Important!

Early cabbage varieties are attacked by the first generation of spring cabbage fly larvae in early May. The second generation, depending on weather conditions, can attack as early as late June - early July.

Summer cabbage fly larvae attack mid-season and late-season cabbage varieties:

• in the southern regions - in mid-June;
• in the middle zone - at the end of June;
• in the northern regions of Russia - in mid-July.

What harm does onion moth cause?

The period of maximum activity of butterflies occurs at night and on cloudy days. It is in the dark that female moths lay eggs. Inexperienced gardeners rarely pay attention to moths fluttering over the beds at dusk. Meanwhile, before the eyes of the farmer, pests choose a place to reproduce. It must be remembered that the onion moth is a serious enemy, which is best neutralized before the voracious caterpillars appear.

Insect larvae do the most damage to plantings. They feed on the pulp of plants, climbing inside the feathers. The leaves turn yellow and begin to dry out at the tips. Sometimes the caterpillars penetrate the bulbs, completely destroying the plant.

Attention! The presence of moth larvae hiding inside the feathers of plants is determined by light stripes on the leaves.

Aphid

Aphids are a common pest that plagues onion beds. The pest is characterized by an ovoid body with a brown color, brown-black eyes, and developed antennal tubercles converging in front. It has 6 segments of the same color as the body of the insect. The larvae are dark yellow or green in color.

An onion planting affected by aphids is determined by a number of signs:

• growth retardation;
• withering and curvature of sheets;
• presence of aphid feces on feathers.

The parasite usually lives on foliage, hiding under the outer shell of the onion.

Competent agricultural technology will help protect vegetation from harmful insects:

• the day before planting, the onions are soaked in hot water;
• “underdog” is not stored together with the main harvest;
• remove weeds in a timely manner;
• Experienced gardeners recommend treating plants damaged by aphid attacks with an infusion of an insecticidal crop such as garlic (pesticides are not used if onions are grown for plumes).

Pest control measures

If onion moths appear in the garden, the first thing the farmer should do is determine whether there are many pests grazing on the crops at that moment. With a small number of parasites, you can do without the use of chemicals. Folk remedies will help get rid of larvae and butterflies. Such compositions are always preferable, because they are safe for the site’s ecosystem and human health.

If there is a significant spread of parasites, experts recommend using insecticides. A prerequisite for the use of chemicals is compliance with the optimal dosages of the drugs indicated on the packaging.

Attention! Chemicals should not be used in the garden 3-4 weeks before harvesting vegetables from the beds. Chemical compounds harmful to human health remain on crops for 30 days.

Chemical methods

If 1/10 of the plantings are occupied by caterpillars, the farmer cannot do without insecticides. Competent farmers spray immediately after the larvae hatch from the eggs.

For your information! Chemical means of combating onion moths give the best results if implemented on calm days. Avoid dripping of the solution onto the ground.

Folk remedies

The effectiveness of natural solutions is significantly lower than chemical ones, but they are safe for people and animals. Most of these products work through repellent scents. Experienced gardeners repeat treatments with folk remedies every week. Such measures in pest control always pay off.

Infusions are prepared based on:

• wood ash;
• fragrant herbs;
• pepper (hot);
• tobacco concentrate.

Scented herbs

Many farmers plant wormwood, calendula, and yarrow next to their vegetable beds. Onion moths cannot tolerate the strong smells of herbs. Decoctions for spraying are prepared based on lemon balm, mint, basil, valerian, tansy, and dandelion. Crushed herbs (200 g) are poured with hot water (10 l.), Infused for 5-6 days. The beds are processed in the evening.

Most gardeners know that onions and garlic are friends with carrots. If these crops are planted nearby, they will repel harmful insects from each other with their smells.

Wood ash

Sometimes tobacco dust is used simultaneously with wood ash as a pest repellent powder. The components are mixed (1:1) and scattered over the garden bed once a week. This remedy works well against adult insects, but is powerless against larvae. Therefore, it is important to get rid of adults in time before they reproduce.

Salt

One of the most reliable and practical remedies for onion moths has long been table salt. It is used dry or a special solution is made. In the first case, young shoots of garlic and onions are sprinkled with salt, and then it is embedded in the soil, loosening the row spacing. Some gardeners enhance this effect with wood ash.

If a farmer chooses to use a saline solution, he should know that “therapeutic watering” must be done 3 times during the season. The work flow is as follows:

• dissolve coarse salt (300 g) in a bucket of water, water the crops at the germination stage;
• make a concentrated solution (600 g of salt per bucket of water), water the crops 2 weeks after the first treatment;
• prepare a saturated salt solution (1 kg per 10 liters of water), water the onion and garlic beds 21 days after the second treatment.

After a few hours, you should rinse the plants from salt residues from the watering can. Additional abundant watering will not be superfluous.

Sweet traps

Some gardeners make sweet traps for parasites. They are constructed from containers filled with sugar water, honey solution, and compote. Moths, seduced by the scent of the bait, drown in it.

How to detect onion fly in the garden

The onion fly itself is invisible and very similar to an ordinary one, so the gardener for the time being does not pay any attention to it. This 6-8 mm long insect is distinguished only by its ashen color, which often allows it to remain unnoticed against the background of dried soil.

It is impossible to see the eggs or newborn larvae of the onion fly until they penetrate the body of the bulb and grow up. But when the worms become visible to the eye, it may be too late to save the crop. Onions affected by the onion fly rot, dry out, turn yellow and are not suitable for further cultivation or storage.

Onion plants damaged by the onion fly emit an unpleasant smell of rotting, which is especially noticeable when loosening the soil next to them.

Onion leaves affected by onion fly

How to fight the onion fly in the garden if it is impossible to see it, and it is very difficult to distinguish it from a harmless one? It is important not to forget about preventive treatments of soil and planting material, which will protect your garden from the appearance of this pest.

Prevention of occurrence

If a farmer properly cares for onion and garlic beds, the likelihood of onion moths being present in the garden is significantly reduced. To create conditions unfavorable for pests you need:

• conduct crop rotation correctly;
• weed the plantings in a timely manner;
• regularly loosen the soil;
• thin out plantings and remove diseased plants;
• plant mustard and wormwood next to the beds.

To destroy moth pupae hidden in fallen leaves, it is necessary to thoroughly clean the beds of plant debris in the fall. Adding organic matter to the soil will also reduce the number of pupated pests.

Attention! If in the spring (before planting) you wash the bulbs in a solution of potassium permanganate, the likelihood of pests appearing on the site will decrease several times.

Any farmer can protect his garden from onion moths if he is not too lazy to regularly inspect the crops and will be able to take timely measures when pests appear. To grow an environmentally friendly crop, you should first use natural means of combating parasites.

If the pest larvae have managed to reproduce, the beds should be treated with chemical insecticides. But the most effective means are preventive measures that exclude the very possibility of onion moths appearing in the garden.

Stem nematode

The most dangerous enemy of vegetables is the stem nematode. Infestation by the pest threatens crop loss. The parasite has the appearance of a miniature thread-like worm (1.5 mm) with a body tapering towards the ends. The nematode sucks juices from vegetation using a needle-shaped stylet in the oral cavity. Her eggs are not visible to the naked eye.

The parasite is active in humid environments. Larvae and adults spoil foliage and turnips. You can identify a planting affected by a nematode by:

• lethargic appearance of the plant;
• thinned areas in affected areas;
• white and brownish spots on onions;
• loose turnips with scales loosely adjacent to each other;
• cracking of heads;
• rotting of the plant or its drying out.

Peak nematode activity occurs in mid-summer. It's difficult to fight her. Agents that destroy the parasite are toxic to the crop.

You can prevent the occurrence of a misfortune by taking preventive measures:

• rotation of crops on the site;
• careful selection of spoiled seed before planting;
• soaking the seeds in hot water (+55 °C) for 15 minutes;
• regular loosening of the soil;
• introducing contact poisons in a minimum dosage on the eve of planting the vegetable.