Winter scoop: photos, fighting measures

Winter scoop (northern locust, winter worm) is an ordinary gray butterfly, in fact it is a dangerous pest. Its field of activity is quite wide: the caterpillar of this insect can spoil up to 20 beet root crops in a day, and 12-14 crawling pests can cope with wheat on one square meter. Corn, melons, rape, tobacco, grapes, tree seedlings, sunflower and the main "weakness" - winter crops - is not a complete list of the "taste preferences" of the winter shovel.

Description of a winter scoop

Externally, the winter scoop (pictured in the article), belonging to the family of nights, is not very noticeable: the front wings are monophonic gray or yellowish-brown, with brown scales, have a clear pattern of wedge-shaped spots and transverse dark-light bands, 46 mm. Hind wings are grayish in females, males are white. The length of the trunk is 18-22 mm. The head and chest of the insect are covered with small hairs, there is a long strong proboscis and an eminence of hairs on the forehead. Antennae: filiform - in females, comb - in males.

Habitat

The territory of the distribution of winter owls is all climatic regions, except arid zones and the Far North. It is common for a pest to produce two generations, in the south - three, in the north - one. In the stage of an adult caterpillar the winter scoop inhabits areas of agricultural land, hibernates in the ground at a depth of 30 cm and is able to survive at a temperature of -11 ° C. With the onset of spring when the soil is heated to +10 ° C, insects migrate to the upper layer and pupate. Month is the period for the full development of pupae characterized by a reddish-brown color, 20 mm in length and 2 thorns at the posterior end. The butterfly leaves the pupa from the lower side of the head part - through the crack. Once freed, the insect, under the pressure of blood in the veins, spreads the wings, which in less than half an hour become suitable for flight.

Periods of mass summer butterflies

In mid-May (in the southern areas - from the end of April), the first generation of butterflies begins, which lasts about three weeks, until about the middle of July. From the middle of this month to the beginning of autumn massively fly butterflies of the second generation.

Summer summer butterfly activity can be determined by setting light traps or troughs with fermenting molasses at a height of 20-25 cm from the ground (part of molasses + three parts of water + 50 grams per liter of water of pre-fermented yeast). The average life expectancy of a butterfly of a winter owl is 5-25 days, the maximum value is 35-40 days.

The winter shovel is most active, the measures of combating which require an integrated approach, at night. The intensified years are observed in windless nights, at a temperature of 12 to 15 ° C above zero.

During the day, a harmful insect hides under weeds of weedy vegetation, heaps of straw, clumps of soil and in other shelters. As an additional food, for optimum maturation of eggs, butterflies use floral nectar.

On the fertility of the winter owl

Oviposition is observed in the second half of August and occurs on vegetable crops, various flowering vegetation, weeds and fields that are designated as winter crops. For this process, the winter scoop chooses well-warmed areas with low grass stand, planting millet, corn, beets and other vegetable crops or a field with a loose soil structure. Eggs in shape hemispherical, white-milk, radially ribbed, in diameter up to 0,9 mm. One female is able to postpone up to 1000 eggs. Fertility of a winter owl depends directly on its nutrition. If flowering plants are absent, there is a mass death of butterflies. According to the experience, females without food lived up to 10 days and laid to 44 eggs; When fed with flower syrup, life expectancy increased to 22 days, and the number of eggs laid - up to 860 pieces.

In regions with a dry climate there were cases of almost complete infertility of butterflies. The advent of favorable conditions contributes to the mass reproduction of the winter owl.

Winter scoop in the stage of the caterpillar

Caterpillars on light appear within 4-15 days and are characterized by a reddish head, a fine-grained skin, pronounced dark strips along the sides, an earthy-gray body 40-50 mm long and eight pairs of legs (three thoracic, five ventral). First they live under the rosettes of the leaves or on their underside and gnaw out small holes; The upper part is not touched. Also at this time, their main food is weeds: sow, swan, bindweed. Caterpillars by means of gnawing cause significant harm to shoots of various crops, sown to cottonseed, maize seeds. It is during the first and second years, until the damage caused to plants has become global, it is recommended to carry out protective measures with chemical and biological preparations.

Scale of the harm caused

In the third age, the caterpillars are always in the upper layer of the soil and crawl upward only to satisfy hunger. Overnight such specimens are capable of destroying up to a dozen plants and feed on different vegetable crops, millet, sugar beet, cotton, melons, maize. Now they already gnaw in the leaves of the hole, then they at all eat leaves, leaving only a central vein.

Caterpillars of the first generation cause damage in June-July, after which they plunge into the soil to a depth of 3-10 cm for pupation. The biggest damage to agriculture is caused by second-generation caterpillars, which damage the sown grain and the emergence of winter cereals.

Winter scoop and measures to combat it

In order to reduce the number of winter scoops and reduce the damage caused by it, the soil needs to be carefully and timely processed, especially by directing activities to:

• Global destruction of weeds - winter scoop food;
• Deep plowing, pre-sowing treatment and loosening of rows, causing the destruction of most of the pupae and caterpillars of a harmful insect;
• Irrigation on irrigated fields;
• Carrying out early sowing of sunflower, sugar beet and other crops, reducing the harmfulness of the first generation of pests;
• Coincidence of cultivation field works with the timing of mass oviposition;
• Removal along roadsides and near cultural plantings of flowering weeds - this measure is aimed at a significant deterioration of the food scoop.

The struggle against winter scoop is effective when spraying plants with such chemical preparations as "Fitoverm", "Decis extra", "Agverotin". With the scoop winter can be fought biologically: the release of Trichogramma, which is required during the period of mass egg laying.