What threatens the appearance of a secretive hunter in the garden

Crypto-carnivores lives throughout the temperate climate — a beetle from the numerous genus weevils. A long narrow proboscis, the length of which reaches almost half of the body, slightly bent down - the "visiting card" of the insect. The appearance of a secretive hunter causes delight and tenderness among children and entomologists. Fans of garden works do not imbue with positive emotions when insects appear on the site. Indeed, most species are pests of crops. What harm can stealthworms do, how to deal with them - let's figure it out.

Biological portrait

In the territory of the former Soviet Union, 75 species of secretive hunters live. Depending on their species, they settle on cruciferous plants, including cabbage, onions, canola, and flowers from the aster family.

What does an insect look like?

In the photo, the crypto is quite a pretty creature. For all beetles from this genus, the following symptoms are characteristic:

• small sizes of an elongated convex body, rarely which adult reaches a length of 4 mm;
• black color with metal bottle, blue, violet, dark brown tint;
• the body is strewn with gray hairs, scales;
• pronotum covered with serrate tubercles;
• club-shaped antennae.

The larvae are a legless, eyeless caterpillar of a white, milky color. The head is small, brown, rusty or dark in color. The eggs are tiny 0.3-0.5 mm long. The shape is oblong, capsule-shaped. Pupa is very similar to an adult beetle, but with an still unformed rostrum and genitals.

On a note! The nutrition of secretive hunters, the form of plant damage is determined by the type of pest, so it is worth considering the most common representatives.

Crypto-onion

The adult beetle covertly hibernates overwinter under plant debris, in ditches, ravines, on the northern slopes. Wintering places leave in early spring. Starving individuals feed mainly on diseased bulbs that have remained uncleaned from last year's crop. When new shoots appear, they migrate to them. Onion Secretive Hunter gnaws a small hole in the green feather, immerses its long proboscis into it and absorbs vegetable juices.

On a note! Adults prefer to eat at night, which can be used during the fight against beetles.

Traces of the presence of a crypto-venom on the onion are manifested by the presence of round whitish spots on the leaves, in the center of which a small puncture is noticeable. Cavities remain on the damaged fragments. The edges of the arrows become jagged, look like a zigzag.

Young shoots of onions, a batun, and also wild onions suffer most of all. Damaged plants often dry out and die.

In April, females begin to lay their eggs in holes gnawed in the feather. Such oviposition is very difficult to detect, which complicates the fight with the crypto-beetle bug.It is interesting that often an adult insect eats up shoots of garlic, but does not lay eggs in it. After 5-15 days, voracious larvae appear, gnawing passages in the pulp of the leaves. Outside, they look like white longitudinal stripes. As you eat, the feather turns yellow, starting from the top.

Attacks of insects rarely cause the mass death of plants. As a rule, the harmful activity of the larvae ends by the end of June and the damaged bows manage to acquire a new feather. But hoping for a good harvest is no longer necessary. The lag of the plant from the growth graphs affects the size of the bulb.

In total, the development of larvae lasts about 3 weeks, after which they gnaw through a hole in the leaf and go into the soil for pupation. At a depth of 3-7 cm they build cradles and in the last days of June new young beetles appear. Newly found individuals gnaw on the testes, pedicels of the bulb, which can lead to the death of flowers and seeds. At the end of the harvest, secretive hunters are removed in search of places for wintering and often they are at a distance of 150-200 m from the bulbous fields.

How to deal with an onion lover

Measures to combat the onion crypto-scavenger involve a series of comprehensive measures:

1. Compliance with the rules of crop rotation - annually plant bulbs on new plantations, beds.
2. At the end of the harvest, carefully remove all plant debris, do not leave the bulbs in the field for the winter.
3. Before planting bulbs, seeds, it is necessary to dig up the soil. Pay attention to loosening the soil, especially in the June days when the larvae go into the ground for pupation.
4. During sowing, a kieselguhr barrier is created around the holes.
5. When white strokes appear on the feathers of onions, the affected plants are treated with pyrethrum powder once a week.

On a note! Traps will help reduce the number of adult bugs. Each bulb is covered with a strip of burlap at the base or covered with “skirts” from corrugated cardboard. Used structures are burned. The method is very time-consuming and therefore is used on small beds.

If onion plantations are extensive, and the pests are well established, they use insecticides: Karbofos, Pirineks, Confidor. To process the seed used "Aktaru". Plants are sprayed in the evening when there is dry, calm weather. Tools are diluted, according to the instructions. The protective effect lasts from 2 weeks to 3 months and depends directly on the insecticide and the frequency of precipitation.

Stalk Stealthy Hunter

The stalk crypto-hunter is characterized by a distinctive feature - the female lays eggs in the stems of plants. Cruciferous crops are attacked by pests: cabbage, turnip, radish. Therefore, the insect is more commonly known as the cabbage secretive.

Successfully wintered adults wake up in early April, when the temperature reaches 8-9 ° C. The primary food is weed from the cruciferous family: colza, shepherd’s bag. When cabbage seedlings appear, stealthworms move to the main power source. Beetles gnaw holes in petioles and leaf veins.

In places of damage, cabbage secretive-minders leave cavities. Subsequently, swellings appear in these areas, commonly called warts. Also, the presence of pests is signaled by holes - holes in the leaves, reminiscent of small windows and damage on the tops of young seedlings.

Already in mid-April, females begin to lay eggs. In the gnawed grooves in the leaf vein, in the stems on the underside, the female lays 3-4 eggs. Given that more than one female is involved in the process, the number of eggs in each plant can be impressive. The total fecundity of the stalked cryptorchid reaches 180-280 embryos.

In just 5 days, fleshy larvae emerge from the eggs. They gnaw a passage leading from a leaf to a stalk.Gradually, the larva deepens down the stem down to the root neck. If the leaves of the cabbage are large, the caterpillars may remain inside it. The moves of the larvae are visible to the naked eye and are brown stripes.

The development of young individuals lasts about 5 weeks, after which they build earthen cradles in the soil and pupate. Hatching young bugs continue feeding on cruciferous crops, and with the onset of cold weather leave for the winter.

On a note! Root is also capable of attacking the secretive rodent. The peak of adult activity occurs in mid-summer. Females lay eggs in the root neck of the plant. At these places galls form. As the larvae develop, the neoplasms increase in size and become like peas.

How to deal with cabbage stealthy scavenger

Pest control measures are largely similar to methods of killing an insect on a bow:

• removal of weeds that beetles feed after wintering;
• regular change of place for landing;
• cultivation of soil between rows;
• thorough inspection of seedlings before planting;
• in cases of severe infection before the heading out, they are sprayed with drugs from the neonicotinoid group: “Aktara”, “Thiacloprid”.

Seminal Secretive Prowler

The pest infects canola, radish, turnips, occasionally cabbage. The name of the seed crypto-scavenger was given for the peculiarity of the female placing eggs, which she lays in young pods. Developing larvae cause significant damage to the seeds.

The rapeseed crypto-hunter is the most troublesome for farmers engaged in the cultivation of crops on an industrial scale. For preventive purposes, observe crop rotation, dry seeds in special dryers, isolate plantings from other cruciferous crops.