The unmatched silkworm (photo can be viewed below) is one of the most famous pests that causes significant damage to deciduous and coniferous trees.
This species got its name for the too big difference between the female and the male. If the female has a massive thick abdomen, and her wingspan reaches 75 mm, then the male is distinguished by a thin abdomen, and the wingspan is only 45 mm. The unpaired male silkworm has brownish-gray wings with dark intermittent stripes. The female has dirty white wings with zigzag black lines.
The unpaired silkworm caterpillar is painted in yellowish color with a dark marble pattern. On the cylindrical body is a rather large head with brown stripes. The newly released young caterpillars are painted black and covered with hairs. Adult individuals reach a length of 40 to 80 cm. Unpaired silkworm-pupa is mummy, dark brown in color, up to 30 mm long.
In warmer areas, butterflies appear from late July to August, in colder areas a month later. Males begin the first years. Females begin to fly a few days later, although they are heavy and prefer not to fly, but to sit on a tree bark. Males fly alive, especially in the evening, in search of females that attract them with pheromones. Fertilized females lay eggs on the bark of deciduous trees. One unpaired silkworm leaves from 250 to 500 eggs. The butterflies themselves will live no more than two weeks, but the eggs will winter, and when the temperature rises to +10 ºC (usually this happens in April), small caterpillars will appear.
The first few days they live together and do not eat anything. But then they creep all over the crown and small holes gnaw out in young leaves, and they eat mainly in the daytime. Older individuals eat foliage in a way characteristic of them, and very often the remains of leaves are scattered on the ground. They have an intensive diet at night, although during outbreaks of mass reproduction they can eat foliage during the day. If there is little food for the caterpillars, then they proceed to the tissues of immature shoots, buds or flowers. After enhanced nutrition, pupation begins. This happens in the first half of July, but in the southern regions - at the end of June. The pupal stage lasts approximately 15 days.
Unpaired silkworms are a fairly multi-eating pest. Over 300 species of plants can damage its tracks. They harm almost all hardwoods and do not pass by the side of such representatives of conifers as fir, pine or larch. Shrubs and fruit trees, cultivated cereals, strawberries, sedge, lingonberries and cranberries are very fond of. Especially viable and prolific is the offspring of unpaired silkworms, if the caterpillars feed on leaves of poplar, oak and fruit trees.
In Russia, unpaired silkworms are distributed practically throughout the entire European part. It also occurs in the Far East and Altai, in the Urals and the Caucasus, in Siberia, Central Asia and Northern Kazakhstan. In the XIX century, it was imported from Europe to the state of Massachusetts (USA) and by 1952 it spread throughout the country, acquiring the status of one of the most dangerous pests there.
