Locust is the world's most dangerous plant pest.
Of all plant pests, the most dangerous is the locust. If there are corners with uncleaned field grasses in the cottage, you can always meet a green filly - a single locust, which over time will provide the appearance of a winged locust form. In 2000, the epiphytotic outbreak of locust breeding left the Volgograd Region without a crop (1000-6000 individuals per sq. M area). In 2010, the pest reached the Urals and some areas of Siberia. Locust flight is terrible. Her flocks can number billions of individuals. When flying, they make a characteristic sound near frighteningly creaky, and in the distance resembling a thunderstorm. After locusts, bare land remains.
Family true locusts (Acrididae) includes up to 10,000 species, of which about 400 are distributed in the Euro-Asian area, including in the Russian Federation (Central Asia, Kazakhstan, south of Western Siberia, the Caucasus, south of the European part). Of the locusts, the most common and harmful for the Russian Federation is locust asian or Migratory locust (Locusta migratoria) There are two life phases: single and herd. The herd form of the locust is harmful. Representatives of the single phase occupy mainly the northern regions of the marked range, and the herd - southern and warm Asian.
An omnivorous pest, with the highest activity in the early morning and evening hours, when there is no peak heat. One individual eats up to 500 g of plants with different densities of vegetative and generative organs (leaves, flowers, young branches, stems, fruits). It covers distances up to 50 km per day. With a gap of 10-15 years, the locust forms huge swarms (swarms) of adults, from the combined accumulations of larvae. During the period of mass reproduction, they can simultaneously occupy up to 2000 ha and fly, eating on the way, up to 300, and with a fair wind up to 1000 km, leaving bare ground with separately sticking out remnants of woody shoots and plant stems.
Under natural conditions, over time, the number of pests decreases (the onset of cold, hunger, the work of natural entomophages). The number of diseases affecting the pest in various stages of development, starting from the egg phase, is increasing in the wings. Recovery lasts 10-15 years and then mass flight is repeated.
Morphological description of locusts
In appearance, the locust resembles grasshoppers and crickets. A visible distinguishing feature is the length of the antennae (locusts are much shorter) and the presence of a curved sharp keel on the pronotum, powerful jaws. The front wings are dense in brownish-brown spots, the hind wings are tender transparent with a yellowish sometimes greenish tint.
Locust development cycle
The life expectancy of an adult is from 8 months to 2 years. Locusts live and develop in two phases / stages - single and herd.
A single locust is distinguished by the general size of its forms, it has a green color, for which it received the name "green filly." She leads an inactive lifestyle and practically does no harm. A single phase of life for locusts is necessary to preserve the population. During this period, females intensively lay their eggs. Gradually, the density of the larvae increases and reaches the limit, which serves as a signal for the transition to the second stage of development and life.
In the herd phase, locust females begin to lay eggs programmed into a camping food search program. Researchers suggest that the “bell" is the lack of protein in the food of adults. Adult locust adults are knocked down in flocks, and the larvae form dense swarms.
Locusts usually die in late October with a steady cold. Before the onset of cold weather, the female lays eggs, forming winter apartments in the upper 10 cm layer of soil, which are called egg capsules. During egg laying, the female locust secretes foamy liquid from the sex glands, which quickly hardens, separating the eggs from the surrounding soil. The female, during the laying of eggs, forms several capsules (egg capsules) with a lid, inside which it places 50-100 eggs, with a total of up to 300 or more. During winter diapause, the eggs become cold-resistant and do not freeze even in severe winters. With the onset of heat, the winter pause ends and in spring, with sufficient soil warming up, a white larva appears in the upper layer of the egg. On the soil surface, it darkens after a few hours, acquires an imago-like appearance (without wings) and begins to feed. Within 1.0-1.5 months, the larva passes 5 ages and turns into an adult locust. After another month of enhanced nutrition, and after mating, the female locust begins to lay eggs. During the warm period, each female forms 1-3 generations.
By way of life, locusts belong to herd species. In years with enough food, a moderately humid climate, and average temperatures, single individuals do not do much harm. But we must take into account the cyclical development and transition from a solitary lifestyle to herd life. It appears after about 4 years. During this period, especially when coinciding with a hot, dry summer period for 2 to 3 years, the locust multiplies intensively, forming huge accumulations of larvae on a small area (swarms). Outbreaks of mass breeding, matching weather conditions, can last for several years, gradually dying out and turning back to a solitary life form. The interval between epiphytotics is on average 10-12 years.
Individuals of the herd form, trying to maintain the protein and water balance of their body, are forced to eat without interruptions (otherwise they will die from their lack of the body). Moving in search of fresh food, they pass, as already noted, from 50 to 300 km per day. One individual is able to eat 200-500 g of green mass of plants and similar neighbors in the swarm. Protein deficiency turns the locust into a predator, and the flock is conditionally divided into 2 groups. One runs away from relatives, the other catches up with them and eats them, and both “along the way of life” are reinforced by plants rich in carbohydrates. A natural gradual decrease in the number of pests is caused by outbreaks of diseases in flocks of locusts at their high density, the defeat of eggs in egg capsules by various diseases, the natural enemies of the locust (predatory insects, birds and other representatives of the fauna).
Consequently, the most vulnerable place in the development of locusts is the increased density of egg laying and the emergence of larvae (per unit area). Swarms of locusts begin their flights with an increased density of pest generation. So, you need to initially destroy the egg clutches and the "islands" of larvae, plowing the land to reduce the density of pests. In suburban areas, the main role of reducing populations is based on integrated pest control measures: agrotechnical measures + chemical treatment of soil and plants.
Locust control methods
Given the speed of movement, voracity and the complete destruction of green plants along the path of the locust flock, chemical control measures are used to destroy it, especially in large areas.
In the country house or in the adjacent area, locust control is mainly carried out prophylactically and proactively and begins with agro-technical measures, the thoroughness and timely implementation of which helps to significantly reduce the number of pests and prevent the epiphytotic harm to the green world of plants.
In areas susceptible to locust attacks, late digging of a summer cottage or house adjoining site is necessary, in which the egg-pods of locusts are destroyed.
In the early autumn digging, deep spring harrowing is recommended. This technique damages the egg capsules laid after an early digging of the site.
When conducting alternative agriculture, it is necessary to tin unused plots, which prevents the formation of egg capsules and egg laying by locust females.
Chemical control measures
All chemical treatments are best done in the morning. When working, observe personal safety measures, work in an appropriate suit, respirator, glasses, gloves. When working with chemicals, you must strictly follow the guidelines for dilution and use of pesticides.
With a large accumulation of locust larvae in separate areas, it is treated with Decis-extra, Karate, Confidor, Image, the validity of which lasts up to 30 days. It can be processed with all drugs that are used to combat the Colorado potato beetle.
The systemic insecticide Klotiamet-VDG provides protection of plants from locusts up to 3 weeks. After 2 hours, all pests die, markedly reduced the number of live hatching larvae. The drug can be used in a tank mixture with fertilizers and growth stimulants with a mandatory compatibility test.
Gladiator-KE insecticide cleans larvae and adult locusts well. Used in the early hours when adults are numb. Doses of the drug vary depending on the age of the locusts.
Damilin is an insecticide with a unique effect on the growth of the pest and the formation of chitin in the body of the larva during molting. As a result, the larvae die before they reach the age of an adult pest. Validity up to 40 days. The drug is low toxic to humans and warm-blooded animals, quickly decomposes in water and soil.