Pest Type: Fruit Pest
Row: Lepidoptera – Lepidoptera
Family: leaflets – Tortricidae
It is found everywhere. Significant harm is done in the steppes and forest-steppes. It only damages the pear.
Butterfly with a wingspan of 17-22 mm; front wings are dark gray with a light brown tint and pronounced transverse striping; the mirror stands out vaguely; the lines bordering the mirror are ribbed gray on the sides; hind wings are gray-brown. The egg is round, 1.3 mm in diameter, with a convex central part and flattened edges, freshly laid – dark red, later gray-red.
Caterpillar 16-20 mm long, gray-white, translucent, with a brown head; abdominal legs with a single-tier rim with 11-17 blunt claws, anal legs with 5-9 claws. Pupa 11-13 mm in size, dark brown; forehead with a conical protrusion bifurcated at the apex, tergal spines on segments of abdomen large, eight hooked setae on the abdominal tip. The cocoon is dark brown, dense.
Caterpillars that have completed their feeding overwinter in cocoons in the soil at a depth of 5-10 cm and under fallen leaves. Pupation takes place 13-20 days after the flowering of the Lesnaya Beauty pear with the sum of effective temperatures (threshold 10 ° C) of 172 ° C in the second and third decades of May. Pupation of individuals of the population is extended and lasts about a month. This extension is inherent in the subsequent stages of the development of the pest. The duration of the development of the pupa is 19-22 days. The years of butterflies in the forest-steppe begin in the second – third, in the Steppe – in the first and second decades of June when the sum of effective temperatures of 370-400 ° C is reached (at a development threshold of 10 ° C). Mass years are observed 8-11 days after its onset. Butterflies are found in the garden until the end of July. Their life expectancy is 9-14 days.
Butterflies are active from the beginning of twilight until total darkness. Females 4-6 days after departure lay one egg per pear fruit. Fertility is 40-80 eggs. Embryonic development lasts 6-10 days. Caterpillar revival begins in the third decade of June when the sum of effective temperatures of 560 ° C is reached. The caterpillars gnaw through the lower shell of the egg and, without coming to the surface, penetrate into the fetus, in which they make a direct passage to the seed chamber. The caterpillar eats all the seeds, filling its shell with brown excrement. Several caterpillars can develop in one fruit. In the place of introduction of the caterpillar into the fetus, a pressing is formed. The caterpillar develops 20-30 days. Leaving the fetus, she gnaws a direct passage to the surface, which ends with a round hole with a diameter of 2-2.5 mm.
The outlet is excrement free. Most of the caterpillars leave the fruits that still hang on the tree, from the second to third decades of July to mid-August and switch to cocooning. Annual generation.
Damaged fruits fall prematurely and rot. Early ripe pear varieties are most severely damaged. Insufficient cold resistance leads to the fact that a significant number of caterpillars die in the low snowy cold winters. Predators and parasites do not play a significant role in reducing the number of pear moths. Caterpillars and pupae destroy many species of predators living in the surface soil layer.
Protective measures. The most effective are agricultural practices and the destruction of plant debris, autumn plowing of row-spacing and tillage in near-stem circles. Loosening of soil in row-spacing and near-stem circles is especially effective during pupation of caterpillars in spring and cocooning in summer. Considering that the caterpillars do not move openly after fruiting, the use of insecticides gives an effect only if spraying is carried out before the beginning of the mass laying of eggs – about 35-40 days after the end of flowering of the pear, when the sum of the effective temperatures of 380-400 ° C (at a threshold of 10 ° C).