The locust is a fairly large insect from the class of Orthoptera. For a long time, it has represented the main threat to cultivated crops.
Descriptions of locusts can be found in such ancient writings as the Bible, the works of ancient egypt, Koran and so on.
Description of the insect
The body of the locust is elongated, the length can reach 20 centimeters. The “knees” of the hind legs are bent, their size is several times larger than the size of the middle and front legs.
There are a pair of hard wing covers, under which are fragile wings with original patterns. When folded, they are quite difficult to notice.
The antennae of locusts are somewhat shorter than, for example, those of crickets, and the head is larger and the eyes are larger. The insect makes a characteristic sound characteristic of males.
The surface of the males' thighs is slightly jagged, and some thickening can be seen on the thighs. During friction, these parts emit a specific sound, which can be of any tone.
Many people believe that the color of a locust depends on its genotype. But actually it is not. The color of an insect has a direct relationship with environmental conditions.
Even individuals belonging to the same offspring, but living in different places, may vary in color.
Another factor influencing coloration is the developmental phase. A younger individual is green in color, and an individual that has entered the gregarious phase acquires the traditional color.
Locusts have the ability to fly; they can travel up to 120 kilometers per day.
The difference between a locust and a grasshopper
The main difference between grasshoppers and locusts is that they belong to different families and suborders. Unlike locusts, the grasshopper belongs to the long-whiskered suborder.
The structure of the paws also differs. The locust's are shorter than the grasshopper's.
Despite their large size, locusts are herbivorous insects, while grasshoppers are predators.
Locusts are active during the day, while grasshoppers are active at night.
For Agriculture grasshoppers are harmless, but locusts often cause colossal harm and huge losses.
These insects also differ in the way they lay eggs. Locusts lay eggs in the soil, and grasshoppers use plant stems for their offspring or lay eggs under the bark of trees.
Locust habitat
Locusts live on almost every continent, with the only exception being Antarctica. Many climate zones are suitable for this insect.
Some species typically live in grassy areas, others prefer to settle in close proximity to water, while others choose semi-deserts as their habitat.
Nutrition
Those individuals that live separately are not known for their gluttony. Over the course of its entire life, one locust can consume up to 300 grams of plants. However, when she gets into a pack, her behavior changes dramatically.
A locust invasion causes enormous harm, since, having met its relatives, the insect becomes omnivorous and begins to absorb everything it sees: reeds, reeds, fruits, grain crops, and so on.
Long flights and lack of food force the locusts to feed on their weaker relatives.
Development and reproduction
During their life, locusts go through three stages of development. 1. Egg; 2. Larva; 3. Adult. The hotter the climate, the more often mating occurs, and, consequently, reproduction.
IN autumn period Eggs are laid, which are kept in a special bag that protects them from damage. One such pouch can hide more than 100 eggs.
After laying eggs, the parents usually die. The eggs remain in the soil all winter and mature.
With the onset of spring, the baby locusts hatch, but they do not yet look like adults; they do not have wings.
It takes 40 days and several molts for locusts to move to the next stage.
One flock can contain more than one billion individuals, and the area that the flock occupies reaches 1000 square kilometers. Such a number of insects can produce a sound similar to thunder.
Currently, there are a huge number of locust species, photos of which you can see below.
Photo of locusts
Of all plant pests, the most dangerous is the locust. If at your dacha there are corners with unharvested field grasses, you can always find a green filly there - a single locust, which over time will ensure the appearance of a winged form of locust. In 2000, an epiphytotic outbreak of locust breeding left the Volgograd region without crops (1000-6000 individuals per sq. m. area). In 2010, the pest reached the Urals and some regions of Siberia. The flight of locusts is terrible. Its flocks can number billions of individuals. When flying, they emit a characteristic sound that is frighteningly creaking up close and reminiscent of pre-storm thunder in the distance. After the locusts, bare earth remains.
Spread of locusts
Family true locusts (Acrididae) includes up to 10,000 species, of which about 400 are common in the European-Asian range, including the Russian Federation ( middle Asia, Kazakhstan, the south of Western Siberia, the Caucasus, the south of the European part). Of the locusts, the most widespread and harmful for the Russian Federation is Asian locust or migratory locust (Locusta migratoria). There are two life phases: solitary and gregarious. The gregarious form of locusts is harmful. Representatives of the solitary phase occupy mainly the northern regions of the noted range, while the gregarious ones occupy the southern and warm Asian regions.
Locust severity level
An omnivorous pest, with the greatest feeding 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). Covers distances of up to 50 km per day. With a gap of 10-15 years, locusts form huge swarms (bands) of adults from united clusters of larvae. During the period of mass reproduction, they are able to simultaneously occupy up to 2000 hectares and fly, feeding on the way, up to 300, and with a fair wind, up to 1000 km, leaving bare ground with separately protruding remains of woody shoots and plant stems.
Under natural conditions, the number of pests decreases over time (the onset of cold, hunger, the work of natural entomophages). The number of diseases in the swamps is increasing, affecting the pest in different phases of development, starting from the egg phase. Recovery continues for 10-15 years and then the mass flight is repeated.
Morphological description of locusts
In appearance, locusts resemble grasshoppers and crickets. A visible distinguishing feature is the length of the antennae (in locusts they are much shorter) and the presence of a curved sharp keel on the pronotum and powerful jaws. The front wings are dense with brownish-brownish spots, the hind wings are delicate transparent with a yellowish and sometimes greenish tint.
Locust development cycle
The lifespan of an adult is from 8 months to 2 years. Locusts live and develop in two phases/stages – solitary and gregarious.
Single phase
The solitary locust is distinguished by the overall size of its forms and has green color, for which it received the name “ green filly". She leads a sedentary lifestyle and does virtually no harm. A single life phase for locusts is necessary to maintain the population. During this period, females intensively lay eggs. Gradually, the density of larvae increases and reaches a limit, which serves as a signal for the transition to the second stage of development and life.
Herd phase
In the gregarious phase, female locusts begin to lay eggs, programmed for a migratory program of foraging. Researchers suggest that the “bell” is a lack of protein in the food of adults. Adult locust adults gather in swarms, and the larvae form dense swarms.
Locust breeding
Locusts usually die at the end of October with the onset of persistent cold. Before the onset of cold weather, the female lays eggs, forming winter apartments called egg capsules in the upper 10 cm layer of soil. During the period of laying eggs, the female locust secretes a foamy liquid from the reproductive glands, which quickly hardens, separating the eggs from the surrounding soil. As the female lays eggs, she forms several capsules (pods) with a lid, inside which she places 50-100 eggs, for a total of up to 300 or more. During winter diapause, eggs become cold-resistant and do not freeze out even in severe winters. With the onset of warmth, the winter pause ends in the spring when the soil has sufficiently warmed up. top layer A white larva emerges from the egg. On the surface of the soil, after a few hours it darkens, acquires an adult-like appearance (without wings) and begins to feed. Over the course of 1.0-1.5 months, the larva goes through 5 instars and turns into an adult locust. Another month of increased feeding and after mating, the female locust begins to lay eggs. During the warm period, each female forms 1-3 generations.
According to their lifestyle, locusts are gregarious species. In years with sufficient food, a moderately humid climate and average temperatures, single individuals do not cause great harm. But we need to take into account the cyclical nature of development and the transition from a solitary lifestyle to a gregarious one. It appears after about 4 years. During this period, especially when coinciding with a hot, dry summer period for 2–3 years, the locusts multiply intensively, forming huge accumulations of larvae in a small area (sweeping pads). Outbreaks of mass reproduction, coinciding with weather conditions, can last for several years, gradually fading and moving back to a solitary form of life. The interval between epiphytoties is on average 10-12 years.
Individuals of the gregarious form, trying to maintain the protein and water balance of their body, are forced to eat without breaks (otherwise they will die from their lack in the body). Moving in search of fresh food, they travel, as already noted, from 50 to 300 km per day. One individual is capable of eating 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 divided into two groups. One runs away from its relatives, the other catches up with them and eats them, and both “along the road of life” are supported by plants rich in carbohydrates. The natural gradual decline in the number of pests is caused by outbreaks of diseases in swarms of locusts at their high density, damage to eggs in egg pods various diseases, natural enemies of locusts (predatory insects, birds and other representatives of fauna).
Consequently, the most vulnerable point in the development of locusts is the increased density of egg deposition and the birth of larvae (per unit area). Swarms of locusts begin their migrations at an increased density of pests. This means that it is necessary to initially destroy clutches of eggs and “islands” of larvae, plowing the land to reduce the density of pests. On summer cottages the main role of population reduction is based on comprehensive pest control measures: agrotechnical measures + chemical treatment soil and plants.
Locust control methods
Given the speed of movement, gluttony and complete destruction of green plants along the route of the swarm of locusts, chemical control measures are used to destroy them, especially over large areas.
In a country house or local area, the fight against locusts is mainly preventive and proactive and begins with agrotechnical measures, the thoroughness and timely implementation of which helps to significantly reduce the number of pests and prevent epiphytotic damage to the green world of plants.
Agrotechnical measures
In areas prone to locust attacks, late digging of the dacha or house area is necessary, during which the egg capsules with locust eggs are destroyed.
When conducting alternative agriculture, it is necessary to tinn unused areas, which prevents the formation of egg capsules and the laying of eggs by female locusts.
Chemical control measures
All treatments chemicals It's best to do it in the morning. When working, observe personal safety measures, work in an appropriate suit, respirator, goggles, and gloves. Working with chemicals, it is necessary to strictly follow the guidelines for the dilution and use of pesticides.
If there is a large accumulation of locust larvae in certain areas, it is treated with Decis-extra, Karate, Confidor, Image, the validity of which lasts up to 30 days. Can be treated with all drugs that are used to combat the Colorado potato beetle.
The systemic insecticide Clotiamet-VDG provides plant protection against locusts for up to 3 weeks. After 2 hours, all pests die, and the number of live hatched larvae decreases noticeably. The drug can be used in a tank mixture with fertilizers and growth stimulants, subject to mandatory compatibility testing.
Insecticide Gladiator-KE effectively removes larvae and adult locusts. Used in the early hours, when adults are in a daze. Doses of the drug vary depending on the age of the locust.
Damilin is an insecticide with a unique effect on the growth of the pest and the formation of chitin in the body of the larvae during molting. As a result, the larvae die before reaching the age of the adult pest. Valid for up to 40 days. The drug is low-toxic for humans and warm-blooded animals, and quickly decomposes in water and soil.
Class: Insects - Insecta
Squad: Orthoptera – Orthoptera
Family: True locusts - Acrididae
Genus: – Locusta
Migratory locust or Asian locust(Locusta migratoria L.) is a polyphagous pest found in Asia, northern Africa and southern Europe.
Morphology of migratory locusts
The insect is large, has a body measuring 30-50 mm, females are slightly larger - 45-55 mm. Body color is brown-green, gray-green, brown-olive. The elytra are oblong, narrow, with a yellow tint or green with frequent dark spots or dots. The wings are fan-shaped, wide, with a green or yellow tint, the edges of the wings are darkened, and at the top they are colorless. The chest is covered with light hairs.
There are two phases - solitary and gregarious. In the solitary phase, which is common in the northern regions of the range, the pronotum does not have a constriction in the middle, the middle carina is arched and high. In the gregarious form, living in the southern regions of the range, the pronotum is saddle-shaped, the middle carina is concave or straight. The capsule is slightly curved or straight, large sizes(up to 85 mm long and up to 10 mm in diameter). The egg capsule is a column of light pink secretion in which the female lays eggs. Each egg capsule contains 40-120 eggs yellow color, 7-8 mm in size, thin, narrowed at both ends. The eggs are arranged in four longitudinal rows, at an angle of 40-45° to the wall of the egg capsule. After laying, the upper side of the egg capsule is in the soil at a depth of 5-7 cm.
Life cycle of the Asian locust
The pest overwinters in the egg stage in a capsule. In May, larvae emerge from the eggs in a white film; after a couple of hours they darken and begin to feed on vegetation. In its development, the larva goes through five instars, each of which differs in the degree of development of the wing primordia and in the number of segments on the antennae. The adult locust actively feeds and 30-40 days after mating, the female migratory locust begins to lay eggs. Each female lays on average three egg capsules (up to 350 eggs). The adult dies in October.
The greatest activity of locusts occurs in the morning and evening.
As mentioned earlier, the Asian locust has gregarious and solitary phases. During the gregarious phase, the larvae unite and form clusters called bands. During the years of mass reproduction, swarms can occupy huge areas, up to a couple of thousand hectares, and fly long distances, up to 50 km, while the locusts eat everything in their path, often leaving behind empty pastures and fields. Migratory locust adults, uniting in swarms, can fly over distances of up to 300 km, and with a strong tailwind, up to 1000 km.
Outbreaks with mass reproduction of locusts last for several years. On average, the interval between population peaks is 10-15 years.
The locust is very dangerous pest, since both larvae and adults roughly eat leaves, stems and generative organs, which can completely destroy plants. One individual locust can eat up to 500 g of green plant matter.
The number of pests in different years reduce various pathogens that affect eggs in egg capsules, and entomophages that destroy larvae and adults.
Methods of protection against migratory locusts
Agrotechnical and organizational and economic control methods include autumn deep plowing, which will help get rid of the wintering form. It is also necessary to reduce possible egg-laying sites, that is, to develop virgin soil, improve forest belts, fight weeds not only in the field, but also beyond it, and get rid of plant residues.
Chemical method of combating migratory locusts
Treatment of large areas is carried out using aviation 20-30 minutes before sunrise, if the wind speed does not exceed 3 m/s. With evening pollination, less efficiency is observed.
To combat a single phase of locusts, poisoned baits are used. To prepare them, you need horse or sheep manure as bait, 12% hexachlorane dust at a rate of 200-400 g and 5-10 liters of water per 10 kg of manure. Baits can be introduced by aircraft, machines or manually.
Chemicals can be used to control the pest regardless of the time of year (from spring to autumn), but it is most effective to treat with insecticides in the spring, before sowing crops. The procedure is repeated a second time in case of a massive pest invasion.
Insecticides of the synthetic pyrethroid group are effective in the fight against migratory locusts: Fastak, Karate Zeon, Tsunami, Arrivo, Gladiator, Taran and others. When protecting against locusts, as a rule, take the maximum dosages allowed by the instructions of the drugs.
If there are older larvae, it is recommended to add organophosphorus insecticides (Fufanon, in an amount of 50% of the maximum dosage) to the solution.
During a locust invasion, the most effective drugs are imidacloprid-based - Confidor, Tanker, Image. They protect crops from pests for several weeks.
Dimilin (active ingredient Diflubenzuron 250 g/kg, wettable powder).
The uniqueness of this insecticide lies in its special mechanism of action: it inhibits the growth of insects - it stops the process of formation of chitin in the body of the larvae, as a result of which the molting process is disrupted and the death of the pest occurs.
The advantages of this drug are: low toxicity to humans, warm-blooded animals and beneficial insect fauna; rapid decomposition in water and soil; long aftereffect period (up to 40 days).
To protect against locusts, insecticide is applied when the pest is in the larval stage of development. The application rate of the drug is 0.14 kg/ha. Used in pastures, areas with wild vegetation, gardens and forest belts.
Migratory locust lays eggs photo
Migratory locust - Locusta migratoriaLocust video
The wingless grasshopper is a critically endangered grasshopper.
The diet consists of green parts of bushes, grasses and trees. Sometimes they harm forest and cultivated plants. Found from May to August. Wingless fillies do not sing.
Appearance of wingless fillies
These insects are short-winged, so they are not able to fly. The eyes of fillies are almost round. The prothorax has a strong protrusion from below.
The color of wingless fillies is brownish-red with black and yellow spots and stripes.
The lower part of the body is yellow, and the upper part is strewn with yellow spots. The elytra are brown, slightly pointed at the apex. Occasionally there are fillies with developed elytra and wings. The thighs are red, and the lower legs and tarsi are light blue with sharp white spines.
Males have black stripes on their abdomen. The body length of males ranges from 12 to 24 millimeters, and females are larger in size - about 18.5-33 millimeters. The antennae in males extend beyond the pronotum, while in females they reach its edge. The lower valve of the ovipositor in males has a large tooth at the base.
Wingless fillies are inhabitants of forests and steppes. Reproduction of fillies
Females lay egg pods containing 16-24 eggs in mid-June. They bury these capsules in the soil to a depth of 20 millimeters. The eggs develop in the soil.
Larvae have 4 instars. The fillies hatch earlier, most often occurring in May. The transformation into an adult insect occurs in June.
Distribution of the wingless filly
These insects live in Europe, Siberia, the North Caucasus, Kazakhstan, Mongolia, Altai and Khabarovsk Territory. They are common in deciduous and mixed forests. Wingless egg capsules live on the edges of forests and in clearings with sparse herbaceous vegetation.
Number of wingless fillies
In the center of our country, the species is found infrequently, and there is a tendency towards a decrease in numbers. There is only one population in the Moscow region.
The reduction in the number of these insects is influenced by the destruction of vegetation. Fires also destroy a large number of vegetation, and due to the winglessness, the dispersal of fillies is difficult.
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10.05.2017
Since ancient times, the invasion of voracious locusts has been considered a terrifying natural disaster. Some flocks, when flying from place to place, form huge clouds of insects in the sky, the area of which can reach thousands of square kilometers and number several billion individuals. The pest devours all the vegetation along its route, so after its invasion only bare soil remains.
The locust is omnivorous and feeds most actively in the early morning and late evening, eating leaves, flowers, young shoots and fruits of plants. During the course of a day, an adult can cover a distance of fifty (!) kilometers, which makes it very dangerous in a crowd of a large number of relatives.
A massive revival of locusts and the formation of a large swarm of pests occurs approximately once every ten to fifteen years. During this period, a huge flock can cover a distance of three hundred to a thousand kilometers per day (if there is a fair wind) and simultaneously occupy an area of about two thousand hectares of land.
The attack of huge swarms of locusts was first mentioned in the chronicles of Rus' dated 1108. As a result of this invasion, terrible famine occurred everywhere. They say that trouble does not come alone, and massive insect attacks were repeated in 1094, 1095, 1103 and 1195.
In 1824, locusts raged in the Kherson, Ekaterinoslav and Tauride provinces.
As part of the fight against this harmful scourge, Alexander Sergeevich Pushkin, among other officials, was sent to the south of Ukraine. Returning from a business trip on May 28, the poet submitted a report to the office with the following content:
Locust
Collegiate Secretary Alexander Pushkin.
Locusts are extremely voracious. Every day, an adult insect eats as much plant food as it weighs, so it is not for nothing that the locust attack became the eighth Egyptian plague and a sign for Pharaoh so that he would finally allow Moses to lead the people of Israel out of Egypt ( Ref. ).
Even now, the locusts, no, no, will manifest themselves. This happens especially often on the African continent, which is facilitated by the hot climate.
The last significant locust outbreaks occurred in the North Caucasus (in 2010 and 2015), and the largest outbreak was recorded in 1875 in the United States, when a huge swarm of insects caused colossal devastation in the state of Texas.
In Ukraine, no evidence of mass reproduction of locusts has yet been recorded, but if the average air temperature continues to rise (and such a trend is visible), then the global warming factor may cause outbreaks of a sharp increase in the locust population in our area.
Locusts are found everywhere, except that they are difficult to detect in the northern regions of the globe, since they are a heat-loving insect and in natural conditions, with the onset of cold weather, the number of insects sharply decreases.
When flying, locusts make a creaking sound, so when a huge colony of insects flies, the sounds of individual individuals merge, amplifying many times, and become an eerie rumble, which from a distance resembles the roar of summer thunder.
Adult (imago)
Total locust family ( lat. Acrididae) has about ten thousand species of insects, but the most harmful are two forms: Asian and migratory ( lat. Locusta migratoria).
The appearance of the locust is unsightly and resembles a large grasshopper or cricket, only with more powerful jaws.
The body of an adult migratory individual can reach six centimeters in length, and the largest can be over fifteen (up to twenty) centimeters.
The wings of an adult insect are greenish with brown spots, the rear ones are transparent and have a green or yellow tint.
The appearance of the winged form of the flying locust is preceded by an ordinary green filly - a single one, which can easily be found on an ordinary sun-drenched lawn with wildflowers.
One adult locust lives from eight months to two years and has two life stages, forms or phases of development. These forms are very different from each other and appearance both physiology and the nature of behavior, so for a long time they were classified as various types locust family.
Currently, scientists perceive both forms as the same species.
Single phase of insect development
The single locust is larger in size and has a rich light green body color, which is why it received the nickname “Green Filly”. This phase of locusts is mostly harmless, since the insect leads an inactive lifestyle and has only one life goal: to maintain the population of insects of its species. Therefore, as long as there is enough food and everything in the locust’s life is going well, the filly lays eggs, giving birth to green fillies similar to themselves. But as soon as food becomes insufficient (usually this happens in dry years), the locust begins to actively lay eggs, the DNA of which contains a “march” program for searching for food, and the density of larvae begins to increase in arithmetic progression. Soon they begin the transition to the second (gregarious) phase of development.
· The gregarious phase of insect development
The gregarious phase of locusts is extremely dangerous. At this stage, the insect acquires a more saturated color, and the body undergoes metamorphosis. The imago becomes more adapted to long flight, and thus the filly turns into a locust.
Adult insects of the gregarious phase begin to cluster into dense flocks as they reproduce.
Scientists entomologists conducted an interesting experiment, during which several mirrors were placed in front of a sedentary female green filly. Soon, constantly bumping into her reflections and conflicting with them, the female began to lay eggs with a nomadic life programmed into them. As it later turned out, the green filly turns into a locust of the gregarious phase due to a banal lack of protein, which causes the female to sharply increase the population of flying individuals.
In years with abundant food and moderate weather conditions without significant temperature fluctuations, single individuals do not cause much harm to plants, so only the gregarious phase of the birth and development of insects should be feared.
Reproduction
With the onset of the first cold weather (usually in October), the locusts die, but before that they lay eggs for wintering, creating egg capsules or capsules (clutches) in which they place from fifty to one hundred eggs. The capsule is produced from the female gonads and has the appearance of a foamy liquid, which, having hardened, becomes a reliable shield for the eggs, thanks to which they do not freeze.
During the summer, one female gives birth to one to three generations of insects.
In the spring, as the earth warms up, larvae emerge from the eggs. white, which soon darken and begin to feed on vegetation. Over the course of about a month, sometimes a little more, the insect larva goes through five developmental stages (instars) until it turns into an adult insect.
The mass reproduction of locusts in the gregarious phase is directly related to weather conditions. Trying to maintain water and protein balance in the body, the flock must continuously feed, so it constantly moves in search of fresh food.
A lack of protein turns some of the insects of the colony into predators and, thus, dividing the flock into two groups. One part, running away from its brethren, seeks food, constantly searching for new vegetation, and the other part at this time replenishes protein reserves, eating, including its relatives.
Pest control
Agrotechnical measures
As a preventative measure against locusts (in those areas where there is a high probability of a massive invasion of harmful insects), it is necessary to carry out thorough and deep cultivation (ploughing) of the soil, which destroys capsules with eggs.
Chemical methods of control
Effectively protecting plantings in the face of unprecedented gluttony and mass numbers of locusts is possible only with the use of chemical methods plant protection.
If there is a mass concentration of locust larvae in one area, use pesticides with a validity period of at least thirty days. To treat and kill insects, they use drugs such as “Karate”, “Confidor”, “Image”, but it is possible to effectively use poisons to combat the Colorado potato beetle.
A good result is shown by the systemic drug “Clotiamet VDG”, which provides reliable protection against locusts for three weeks. This poison is good because it can be effectively used in a tank mixture with other microfertilizers, protective agents and plant growth stimulants, but it is necessary to first test for compatibility with other chemicals.
Preparations such as “Gladiator” and “Damilin” effectively destroy locusts (both larvae and adult insects). The insecticide "Damilin" has a negative effect on the larvae, slowing down their development and disrupting the timing of the formation of the chitinous body shell, as a result of which the insects die.
The big advantage of the drug is its low toxicity.
