The Colorado potato beetle belongs to the family of leaf beetles from the order of beetles, which number about 35 thousand species in their group. The matured individuals and larvae of the Colorado potato beetle feed on foliage of plants belonging to the nightshade family, including potato and tomato crops, peppers, and eggplants, damaging crops and being pests dangerous to the agricultural industry.
Homeland of the insect
In Latin, Leptinotarsa decemlineata is also called a potato leaf beetle in nature. The first to know about his presence among the fauna in 1824 was due to the research of an American, by the profession of biologist Thomas Saye. He gathered unknown representatives on nightshade cultures and brought from the Rocky Mountains to a mountain range in North America. Since then, the taxonomy, classification, and determination of its place in insect families began.
The name potato leaf beetle was acquired after it destroyed potato crops in the fields of the US state called Colorado.
Its true homeland, where the Colorado potato beetle came from and where it takes its origin, is the Mexican northeastern part, where other species of the Leptinotarsa species, feeding on nightshade and tobacco plants, are also found. From the Mexican Sonora province, a potato leaf beetle migrated to the northern parts of the continent.
Geography of distribution
The primary damage to potato plantings by pests was recorded in the US state of Nebraska. Subsequently, a map of his appearance spread across all of North America. At the end of the 70s of the 19th century, individuals moved and crossed the Atlantic Ocean along with cargoes on steamboats, appearing on European territory, where it lives to this day. He was able to finally take root in his many habitat settlements at the end of World War I.
Potato leaf beetle is common and is found in almost all countries of the European continent except Britain, where it is still not found or difficult to find.
In Russia, individuals of the Colorado potato beetle appeared during the Soviet era. Soviet gardeners got acquainted with information about them from the 40s of the last century. The mass spread of the insect, where the Colorado potato beetle came from as a result of Russia, occurred in conjunction with the wagon loaded with straw wagons from the Ukrainian Republic, the 1975th year of drought.
Appearance features
Adults
The description of how the Colorado potato beetle looks refers the insect to large enough, reaching a length of 8 to 12 mm, in width – from 6 to 7 mm. The insect has a fairly memorable appearance, according to which it is difficult to confuse it with other representatives in the leaf beetle family. The characteristics of the insect’s appearance include its distinctive features, which distinguish the leaf beetle from other pests:
- oval body with a strong convex top and brilliant yellow-orange color,
- the insect pronotum is spotty, with black speckles,
- both of the two elytra are decorated with five black stripes.
It is believed that the name of the potato beetle owes an extraordinary predator-preventing mask because of five black stripes on each of the elytra.
The abdomen of the insect consists of 7 segments with black spots arranged in a row. The potato leaf beetle has 3 pairs of paws equipped with hooks to help the insect move along the surface of the leaves and stems of the potato plant.
In nature, there is the so-called false potato beetle (in Latin Leptinotarsa juncta, or Lj), externally and in structure it looks very similar to a potato leaf beetle.The false representative in the USA is widespread and differs from the true potato in the form of elytra and orange coloring of the paws.
The insect is able to cover long distances thanks to its well-developed wings with membranous structure.
Weight adult potato leaf beetle is about 140-160 mg, young individuals of the Colorado potato beetle are slightly smaller in size and weight.
Description
According to the description, the larva of the Colorado potato beetle grows up to 1 in length , 5-1.6 cm, she has a black head part and with b Cove has two series of black dots. This description of the larva is similar to the appearance of the ladybug larvae, which are often confused with each other. In color, the larva of the potato leaf beetle is initially dark brown, but in the process of its development, it turns bright yellow, sometimes with a pink tinge. The color of the larva depends on the presence in its hemolymph (circulating fluid inside the vessels) of a yellow-orange pigment called carotene. When eating foliage of potatoes and other nightshade, which the Colorado potato beetle eats, the larvae are not processed, but accumulate carotenes inside, which paints them in the color of carrots.
Life cycle of adults
In terms of average indicators, the duration of the life of the Colorado potato beetle and all stages of development of the Colorado potato beetle rarely exceed 1 year. A specific feature of an insect is its ability to stay in diapause.This is a special condition, as an adult Colorado potato beetle overwinters, in which the physiological phases of metabolism are inhibited and morphogenesis stops. Some representatives, staying in the diapause in the cold season, survive in such conditions up to 3 years of age.
The number of young generations of potato leaf beetle directly depends on climatic conditions. In the northern regions, it displays one generation, in the southern regions their number reaches 2-3.
The beetle eats the plant part of the potato
Imago potato leaf beetle winter in the soil, climbing to the depth. The distance from the surface to the place where the Colorado potato beetle hibernates can be up to half a meter. When spring heat sets in, it gets to the surface and begins to feed on plant shoots, at the same time starting the mating process.
From the beginning of the spring season until the arrival of autumn, adult females lay an oblong egg of light orange color on the underside of leaf blades . In one day, each of them can postpone from 5 to 80 pieces. In total, for the entire summer period, the female Colorado potato beetle is able to lay about a thousand eggs.
The life cycle of larvae
The larvae appear 5-17 days after the laying of the female eggs, and this period depends on the ambient temperature. There are 4 age periods in the development of the life cycle of Colorado potato beetle larvae, which are divided by molt:
- 1st-instar larva of dark gray color, reaching a length of up to 2.5 mm, covered with small hairs, it is able to gnaw leaf flesh from the bottom,
- individuals of the 2nd larval age are red and grow to a length of 45mm, they destroy the entire leaf flesh, leaving intact one thickened veins located in the middle of the leaf plate, settling at the top of the shoots,
- 3rd instar larvae red with yellow m in length up to 9 mm and 4th age, orange up to 16 mm long spread to neighboring plants, eating foliage and stems.
Larvae are able to feed very intensively, and after two to three weeks they ready for the development of a new stage and turning into a chrysalis, for which they burrow into the soil layer to a depth of 10 cm.
After a two-three week interval, a pupa of the Colorado potato beetle forms under the earth. Subsequently, the grown insect crawls out of the pupa to the surface or goes into a diapause state until the next spring season arrives.
Life cycle of the young generation
Young insects newly emerged from under the layer of earth from the pupae stand out from the rest with their bright orange color and softened skin. However, after a few hours (usually this happens after 3-4 hours) they become darker, brown in color with a slight pinkish tinge, eventually acquiring the color familiar to ordinary adult insects.
When a danger arises, a potato leaf beetle does not leave its place and does not fly away, but freezes, pretending to be dead.
An adult pest begins to eat and accumulate fat reserves, increasing in size and gaining weight over 6-20 days, eventually becoming ready for reproduction and movement. They begin to make flights in the hot summer time or before wintering. The grown insects fly dozens of kilometers in the summer, forming new settlements of their colonies. Moreover, the speed of their movement can reach up to 8 km per hour.
Damage and sources of occurrence
Insect invasion can ruin the crop
The beetle mainly harms agriculture and especially potato varieties.
What is the harm of the insect
The insect eats vegetable crops and is capable of destroying most of the crop in a short period of time.Called a potato parasite in gardeners, the beetle feeds on all parts of the plant — young stems, foliage, and root crops. At the very beginning of the gardening period, the juicy young greenery of the vegetable bush becomes its source of food. Toward the middle of summer, he begins to eat plant inflorescences, and by the end of the growing season, move to the lower tier, damaging foliage and potato tubers.
Sources of appearance
Appear on In an infield, the insect can come from various sources:
- when the first warm days begin, the beetle flies from neighboring gardens where the favorite crops for the pest have ceased to plant,
- most of it is selected on the soil surface after wintering,
- some insects settle on new m flight by mass flight due to dramatic climatic changes or with local use of agrotechnical measures, and flights can take place over rather long distances.
Methods of struggle
Measures against potato leaf beetle include quarantine measures and the processing of potatoes and other vegetable crops with insecticides at the stage of second-instar larvae and during mass birth of enormous harm to young Colorado potato beetles.
Potato leaf beetle and high resistance to toxic chemicals, which complicates the fight against the pest.EPV (economic threshold of harmfulness) of the pest reaches 40 individuals per 100 sq.m.
Many gardeners on small sown areas destroy the pest by manually collecting it from vegetable bushes, given that it is on the foliage
Natural enemies
For most birds and many animals, the pest is inedible. This is because, in the process of feeding on nightshade crops, a potato leaf beetle accumulates toxic substances alkaloids and solanins in the leaf part and stems of plants in its body.
The pheasants are the same feathered bird that eats the Colorado potato beetle. They feed on its larvae of ground beetles and lacewings. Colorado potato beetles are guinea fowls Matured individuals can become food not only for guinea fowls, but and for turkeys. For this purpose, from a young age, I add a crushed insect to the feed of a crushed insect. Among natural enemies who eat a Colorado potato beetle, in addition to birds, there are a number of bedbugs – shield bugs and tahini flies.
