Pest type: Pest of cabbage crops
Row: Coleoptera - Coleoptera
Family: leaf beetles - Chrysomelidae
It is found in the steppe and forest-steppe zones. It damages cabbage, rape, radish, turnip, mustard and other cabbage plants.
beetle 7-10 mm in size, elongated oval, yellow-black on top with longitudinal black stripes along the seam and in the middle of the elytra, shield, middle part of the anterior and with 11 segments, black antennae. The egg is 2.0-2.5 mm in size, black-brown, oblong, its surface is hard. The larva is 13-16 mm long, the dorsal surface is brown-brown, the abdomen is yellow, the body is covered with dark warts and tubercles, on which the bristles are placed (when touched with warts, a caustic sticky substance is released). The pupa is 9 mm in size, yellow-black.
The rapeseed leaf beetle winters in the egg stage, and sometimes the larvae in the surface layer of the soil. Larvae hatch in the south - at the beginning of April, in the north - in the first decade of May, they feed on cabbage weeds, often in different species. In the case of mass reproduction damage cultivated plants (cabbage, radishes, etc.), eat leaf flesh, leaving thick veins. Larvae develop 15-28 days. They pupate in the soil at a depth of 5-8 cm in dense cocoons.
Baby doll develops 14-20 days. At the end of May - in June, beetles come out, which feed on leaves, flowers and pods of various cabbage plants. In summer, at high average daily air temperatures, the beetles burrow into the soil to a depth of 15–20 cm, where they remain in a state of summer dormancy until autumn. In late August - in September, beetles come to the surface of the soil, feed on various cabbage plants, then mate. Females lay their eggs in the surface layer of soil from August to November. Fecundity-180-250 eggs.
In the fall, the larvae that hatch in the soil until spring can hatch from early laid eggs. For a year one generation develops.
Protection measures Autumn soil cultivation. Destruction of weeds from the cabbage family. Loosening the soil between the rows. In the case of a pest infestation, 10% of plants and with an average density of 5-6 or more individuals per plant are sprayed with insecticides.
Description of the species
Rapeseed beetle (Entomoscelisadonidis) - an insect of the beetle order, the leaf beetle family. The body of an oval-shaped beetle with convex sheaths. Size 7-10 mm, males smaller than females. The color is bright - red-yellow with a distinct pattern. Pronotum has wide median and two lateral specks of black color. Three longitudinal black stripes run along the sheaths - two on the sides and one along the seam.Rapeseed leaf beetle
Interesting fact. A characteristic feature of leaf beetles is the ability to retract paws and antennae under the body so that they are not visible from the side.
The head is covered with a solid capsule, passing into the prothorax. Eyes are rounded. Antennae beaded, consist of 11 segments, directed forward. Oral organs of the gnawing type, the jaws are adapted for grinding vegetable food. Upper lip, clypeus and crown black. Apical angles are rounded, and elytra are rectangular. The lower body and limbs are colored black.
Elytra covered with rows of punctation. Below them are well-developed wings used for flying. The photo shows that the wings of the rapeseed leaf beetle are transparent with pronounced venation.
The abdomen, completely hidden by the elytra, consists of 5 sternites and 6–8 tergites. Feet walking type. The coxae of the fore and middle extremities are fixed movably. The paw is broadened and flattened, with many hairs on the sole. Flattened shin on top with one noticeable spur.
Lifestyle and reproduction
Beetles are found in the dry areas of the forest-steppe and steppe zones, mountainous areas at the height of alpine meadows. The rapeseed leaf beetle lives openly on forage plants, disturbed adults fall to the ground. One of the worst enemies of the insect are horsemen and tachina flies, which parasitize on the larvae. At high humidity, up to 18% of the offspring are affected.
In early summer, imago crawls out of the soil. They feed on cruciferous flowers and leaves. They are not ready for reproduction and need additional food, which lasts about two weeks. In the hottest period of summer, the beetles begin diapause. Insects stop feeding and burrow into the soil to a depth of 15-20 cm. The imago returns to activity in late August or early September. The breeding season begins. At this time, beetles feed on cabbage pods, eat away seeds. Leaf beetles fly well, with the deterioration of the conditions of existence of the imago master new territories. After breeding, the beetles die.
Females lay oval eggs of a reddish-brown color in the upper layer of the soil. Their length is 1-2 mm, the number - 150-280 pieces. Eggs overwinter in the soil, but progeny have time to appear from them in a lingering warm autumn. In this case, the larvae of the first age are sent for wintering. Usually the larvae hatch in early spring, in April. Their bodies are elongated, spindly.Breeding leaf beetles
Initially, the color is yellow, after molting the upper part becomes dark brown or black, and the lower part is ocher yellow. Body length 14-15 mm. On each segment there are several warts with hairs. Large head and three pairs of black limbs. Development takes 10 to 28 days. Larvae follow four ages. When the temperature drops below 10 °, burrow into the soil.
Information. The imago and leaf beetle larvae have a protective mechanism. In case of danger, they emit an unpleasant-smelling caustic substance.Larva of rapeseed leaf beetle
Imago damage winter rapeseed, cabbage seedlings. In normal years, the damage is insignificant. The species is dangerous in the south of the European regions of Russia, where most of the offspring survive in favorable conditions. The larvae are inactive, they do not crawl away from the place where the eggs were laid. At the end of May they are buried in the soil at a depth of 6-10 cm, where they pupate in an earthen crib. The pupa is red-black, 10 mm in size. The pupal stage lasts 8-10 days. If the air temperature is below 20-22 °, then delayed up to 20 days.
Young larvae feed on cruciferous weeds - a shepherd's purse, wild mustard, and a wild field. If there are agricultural crops of cabbage and oilseeds close by, move to them. Pests during mass breeding outbreaks pose a particular threat to crops. Beetles devour the flesh of the leaves, leaving only the cruciferous veins, flowers and pods. They prefer to eat on cabbage, swede, mustard, radish and rapeseed.Leaf-beetle imago eat crops
Information. Depending on the region, 1-2 generations of rapeseed leaf beetles develop per year.
Physical and agrotechnical activities
To protect cabbage crops from damage, you must perform the following steps:
- Timely destroy weeds in the area. Wild cruciferous crops are the food supply of insect pests.
- Autumn plowing of the soil, carried out after laying eggs by females of rapeseed leaves.
- Summer soil loosening around cabbage crops and between rows helps to remove pests from the soil and destroy the pupae.
- On a small individual site, high efficiency is given by manual collection of imagoes and leaf beetle larvae. Collected beetles destroy.
- Early planting of cruciferous plants is recommended.
- One of the tricks of farmers is planting small areas of rapeseed that distract leaf beetles from the main crop.
When more than 5-6 adults are found on a single plant, it cannot do without insecticide treatment. Agricultural fields are pollinated with 12% hexachlorane dust at a dosage of 10-20 kg per 1 ha. It is a powder of white or gray color, which is a poison of contact action. Insecticide solutions are also used: Phobecid, Karbofos, Zollon, Aktellik, Metafos. Processing is performed in the evening when insects sit on the tops of the leaves.Insecticide against leaf beetles
Contact and enteric contact chemicals enter the body of beetles with food. Within a few hours they cause paralysis, disrupt enzymes and the transmission of insect nerve impulses. The protective effect of insecticides lasts 2-3 weeks.
Rapeseed Beetle: Description and Behavior
The leaf beetle is a small insect, its dimensions do not exceed 10 mm. The body is rounded, elongated, with a durable chitinous shell. The main difference from other pests - bright color with contrasting red and black stripes. On head long black antennae, consisting of 11 segments. The legs have a similar structure.
Larvae of leaf beetles are larger than adult insects, the upper part of the back is colored brown, the lower part is muted yellow. On the surface of the body there are many tubercles with bristles; when touching the warts, the larva secretes a sticky substance with a characteristic odor. After pupation, the insect acquires a red-black color.
The leaf beetles overwinter in the upper layers of the soil in a state of larvae. In the spring they come to the surface and complete the development process, turning into adult insects. In the southern regions, leaf beetle leaves at the beginning of spring, in the middle lane leaf beetles appear in the first decade of May.
Beetles parasitize cruciferous weeds, but later move to cultivated plants: cabbage, radish, canola. Insects eat away the soft part of the leaf, leaving only streaks, which becomes the reason for the early death of seedlings. Larvae are particularly voracious, but after turning into adult beetles, they continue to feed on the leaves. When the heat comes, the leaf beetles burrow into the soil, coming to the surface at the end of summer or early autumn, when mating and laying eggs take place.
Experts identify many types of leaf beetles. In addition to rapeseed in the gardens there are also asparagus, mint, strawberry, willow, viburnum, strawberry. Many species can be destroyed by the same methods as rapeseed beetles.
How to get rid of the beetle at home
To protect the landings, it is necessary to combine preventive measures with active insecticides. At the end of the season, the land intended for planting is carefully dug up. This simple measure will help destroy the eggs laid by the females and reduce the insect population.
With the first warm days you need to start weed control, paying particular attention to cruciferous plants such as colza. Not finding a nutrient medium, the larvae will leave the garden. At the same time, frequent loosening of aisles and land under planting is necessary.
Cabbage should be planted as soon as possible. To protect young plants will help greenhouses and greenhouses, the land in which heats up in the middle of spring. In small areas, you can catch adult beetles with a net, but for large areas this measure is not suitable.
If several adult insects are found on plants, do not waste time on prevention. It is necessary to move to more stringent measures, abundantly using industrial insecticides. Among the most effective drugs "Kemifos", "Detsis", "Aktellik", "Phosbecid", "Zolon". The compositions are diluted in accordance with the recommendations on the package. The drugs are quite toxic, they must be used purposefully and for a short time. Solutions help to destroy not only leaf beetles, but also other parasites: ticks, fruit fleas, locust.
What are leaf beetles?
Leaf beetles are small or medium-sized beetles, whose body length is about 3-5 mm. Insects are usually bright colors, and the shape of their body can be varied. Representatives of some species are very similar to the ladybug. In addition, the feature of leaf beetles is that they, like the ladybirds, are capable of hiding their legs under them. This may explain the fact that in the sitting position their limbs and antennae are imperceptible.
Adult beetles have antennae directed forward, which consist of 11 segments. In some individuals on the forehead, characteristic tubercles can be found. The eyes are rounded. Leaf-beetle insects are endowed with well-formed wings. Many of them have long hind legs, with their help insects can jump. Leaf beetles differ in sexual dimorphism - females are somewhat larger in size than males.
Larvae of leaf beetles can also be diverse. Their appearance mainly depends on lifestyle, but the common characteristic feature for all is an undeveloped throat, 1-3-segment antennae and 4-segment legs.
Main species of leaf beetle
Among the most famous types of leaf beetles are the following:
- Alder leaf beetle, which is also called alder kozyavkoy. The larvae of this insect feed on the leaves of the gray alder, and the diet of adult beetles is black alder. The oval torso of the imago is colored dark blue with a beautiful metallic sheen. Its length is -5-7 mm.
- Poplar leaf beetle can be recognized by the black body with a green metallic sheen and chest shield. Elytra are red in color. The larvae of the leaf beetle of this species feed on the leaves of poplars, willows and aspens.
- The color of the trunk of the beetle leafer is dark green with a bronze tint. Bottom of the body of the insect is painted green with a metallic sheen. The larvae feed on the roots and leaves of Hypericum, and the adult leaf beetles feed on the kidneys of this plant.
- The cabbage leaf beetle has an oval shape, its color is dark green with a metallic sheen. Insect size 3-5 mm. Cabbage leaves are eaten by both larvae and adult insects. By this they cause significant damage to the crop.
- The body length of a strawberry leaf beetle is 4-5 mm. It is painted in an unsightly light brown color. A large number of larvae and imago, eating strawberry leaf plates, can destroy almost all the leaves in the garden.
- The Colorado potato beetle is also a well-known representative of the leaf beetles. Compared with other species, the insect is quite large in size - 10-12 mm. The body is convex, has a bright yellow-red color. On elytra there are longitudinal black stripes. This leaf beetle is considered one of the most dangerous pests for plants of the nightshade family, especially potatoes.
- Herbal leaf beetles belong to a large genus of coleoptera, which has about 460 species and 250 subspecies. These small bugs (8-10 mm) feed mainly on plants of the Astrov family (tansy, wormwood, chyhotnik), borage, yasnotkovyh (marsh moth and water) and balsamic. These insects lack the ability to fly, therefore, they spend almost their entire lives next to fodder plants.
- Rape leaf beetles are distinguished by their elongated ovoid body shape. Insects have long antennae and prominent elytra, which cover the abdomen. The adult beetle is colored black, and its crown, elytra and sides of the pectoral scapular are yellow-red. It is a pest of cruciferous plants.
- The body of the onion leaf beetle has an oval shape with a length of 6-8 mm. A large head with bulging eyes located on the ledges on the sides. Larvae and adult beetles feed on flowers, leaves and onion stalks. In addition, asparagus, garlic and lilies suffer from this leaf beetle.
From the name it is clear that these beetles live due to the fact that they eat the leaves. The larvae can live right on the leaf plates, on the roots of plants in the ground, on the stems, and sometimes under water.
The leaf beetles in their majority eat the leaves of forage plants. Some of them can eat some specific plants, others - any kinds of vegetation. There are species that prefer the fallen leaves and animal corpses.
The scraping surface of the leaf plate, the larva or adult beetle makes a hole in it. However, such damage does not always indicate that it was made by leaf beetles. Such openings can be left by the larvae of sawflies, caterpillars, snails, slugs, weevils and grasshoppers.
With intensive breeding of leaf beetles, their number grows very quickly. They occupy most of the leaves on trees, shrubs and garden plants. As a result, if necessary measures are not taken, all leaves can be destroyed. Sometimes plants suffer from damage to the roots by the larvae of some leaf beetles. However, they do not cause significant harm to strong and robust specimens.
Among the leaf beetles there are both pests of cultivated plants and trees, as well as beneficial insects that help fight weeds. Pests cause significant harm to cabbage, strawberries, eggplants, potatoes, peppers, tomatoes, beets, tobacco, cereals, radishes, rapeseed, horseradish, onions, garlic.
In addition, leaf beetles damage the leaves of alder, poplar, birch, willow and alder. However, along with this, there are species that destroy St. John's wort, ambrosia, nourishment, and other weeds.
How to deal with leaf beetles?
Features of struggle with leaf beetles depends on the species to which they belong. Например, при обнаружении земляничного листоеда, сначала нужно избавиться от сорняков, например, таких как гусиная лапчатка и таволга, поскольку вредитель очень часто на них обитает. Обрабатывать земляничные кусты можно только некоторыми видами пестицидов. Обычно используют 10% «Карбофос» (70 г/ 8-10 л воды) или «Каратэ» (2-3 мл/8-10 л воды).
At the end of fruiting, it is important not to forget from time to time to loosen the soil under the bushes - in this simple way the pest pupae are destroyed. To compensate for damage from beetle attacks, you can use drugs to stimulate the growth and development of strawberry bushes. In order to scare away leaf beetles at the beginning of spring, it is possible to pollinate plants using tobacco dust.
It is somewhat more difficult to fight onion leaf beetles, since planting garlic or onions cannot be sprayed with chemicals. To protect against pests, you must regularly get rid of weeds, strictly observe crop rotation, collect beetles by hand, and in the larval stage spray plants with effective infusions prepared on the basis of high larkspur or wormwood. To fight with onion leaf beetles need a complex, and not only apply one method.
Before you fight a Kalinov leaf beetle, you need to cut off and destroy dry inflorescences and branches - thus the pest population is reduced. During the summer, it is necessary to collect adult insects and larvae by hand. The following insecticides can be used to combat Kalin leaf beetles: Fosbucid, Actellic, Kemifos, Lightning. The most effective will be spraying one of these drugs in the period of the mass appearance of larvae and the release of imago.
To prevent the occurrence of pests of the leaf beetle family, use the following methods:
- pruning and destruction of shoots and branches damaged by adult insects or their larvae,
- collection of adult pests and larvae by hand,
- reproduction in places where pests have settled, insects that eat their eggs. An example would be a ladybug,
- spraying plants affected by leaf beetles with special chemicals,
- the use of folk remedies, in particular, spraying the affected plants with bitter pepper, chamomile or tomato extract.
This beetle has dimensions of the order of 7-10 mm, the body of its oblong-oval shape, the upper part of the body wears a red and black color, has three longitudinally located strips - one along the seam and two on both sides in the central part of the elytra. The middle part of the body passes into the head, on which is located one pair of antennae of black color, numbering 11 segments. The legs are six, all in structure are like a mustache, only thicker and also composed of segments.
The larva has a body length of 13-16 mm, the surface of the back has a brown-brown color, and the lower part is colored yellow. The entire larva is covered with dark bumps and wart-like formations, on top of which the bristles are placed. If you touch warts, a glue-like substance with a sticky odor is released. The pupa also has a black and red color, its size is about 1 cm.
Spread and harm
After wintering in the form of eggs or larvae, which takes place in the upper layers of the soil, adult forms develop. In the south, it usually occurs in the middle of spring, and in the north a little later, in the first third of May. At first they parasitize on cabbage weeds, but as the population grows, they move to cultivated plants such as canola, radishes, cabbage, etc. Beetle-beetle eating the flesh of the leaves, leaving only hard streaks, which, in turn, leads to the immediate death of plants.
After a period of development that lasts for 15-28 days, the larvae turn into cocoons, as a rule, lying in the ground at a depth of 5 to 8 cm. Then, 14-20 days later, the process of development of the final forms ends, and they come to the surface bugs that continue to feed on various cruciferous cultures.
With the onset of summer heat, imagoes burrow into the soil to a depth of 20 centimeters and remain in a state of summer rest until the onset of autumn. At the end of August or at the beginning of September, depending on the temperature regime, the bugs get out onto the surface and immediately mate.
Females lay eggs in the surface soil layers, while the fecundity of one individual can reach about 250 eggs. In one year, only one generation of this pest develops, but sometimes this is quite enough so that the crop suffers significant losses.
How to deal with rapeseed leaf beetle
Control measures applied against this pest include the use of agrochemicals and physical methods. More effective, no doubt, are the first. Remember also that by delaying the transition to the use of insecticides, you risk losing even more of your crop.
This set of measures includes the following activities:
- Cultivation of soil in the autumn. It would be ideal to hold this event directly after laying beetle eggs by females, namely in the first third of September.
- Elimination of cabbage weeds on your plot. This will lead to the fact that the larvae hatched in the spring from the eggs will not find a nutrient medium for themselves and will leave from your vegetable garden.
- Periodic preventive soil loosening, including between the rows. Produced to destroy harmful pupae.
- Early cabbage planting.
- Catching adult beetles and larvae using a net. However, this measure will be effective only in areas of small size.
- If you want to protect from the influence of these pests any other crop other than rape, it is recommended to plant the latter close to plants that need protection. This beetle with a high degree of probability will prefer rape to any other culture.
Use of drugs
The chemical industry has developed many different insecticides to control insect pests, including the described beetle. However, it is worth remembering that each of the preparations has individual methods of preparation, concentration and consistency of the finished solution and methods of application.
Remember also that the majority of insecticides are dangerous to humans, so do not neglect the methods of personal protection. The best means against rapeseed leaf beetle are considered "Phosbecid", "Aktellik" and "Zolon".
Other rape pests
Canola is a plant susceptible to a huge number of pests and diseases. Here is a short list of them:
- Cruciform flea. In addition to rape, all cruciferous plants are also striking: cabbage, radish, mustard, etc.
- Cocktails rapeseed ordinary. In addition to all crucifers, it can also eat on a walker, radish, turnip.
- Skullcaper's rapeseed seed. It is interesting in that it feeds on young seeds from the inside, after eating which it gnaws a pod and moves to the upper layers of the soil.
- Cabbage mosquito pod. The main damage is caused by the larvae, whose vital processes interfere with the flowering of crops such as rapeseed, cabbage and turnip, to normally open.
- Rape sawfly. For the year, two generations of this pest develop. Deals damage to absolutely the entire ground part of the plant.
- Rapeseed flower eater. They feed on rapeseed. The greatest damage is caused by winter and spring rapeseed plantings in the process of destroying the buds.