Rusty tussock moth (Orgya antiqua)
Rusty Tussock Moth
Orgya antiqua Linnaeus
Разред Lepidoptera, Сем. Erebidae
Order: Lepidoptera, Family: Erebidae Hosts
The caterpillars of the rusty tussock moth damage fruit and landscape crops such as apple, pear, cherry, sweet cherry, roses, mountain ash, and others, as well as forest trees, particularly willow, poplar, birch, and larch. They also cause damage to currants, wild roses, maple, linden, black currants, and blueberries. Minor damage has been reported on clover and soybeans. In fruit orchards, they cause damage in the zone of two generations. The caterpillars feed on round buds, leaves, and flower buds.
This moth is found in Western Europe (excluding the far north), Asia Minor, Mongolia, China (including Tibet), Korea, and North America (in the forest zone).
Flight Behavior
Females fly in the afternoon hours; non-flying females typically wait for the males on the surface of their cocoons, where copulation occurs. Young caterpillars of the first and second instars can withstand cold temperatures as low as -5°C. The caterpillars migrate passively over long distances with the help of wind. The optimal temperature for caterpillar development is 20°C, and the lower development threshold is -10°C. The lower cold resistance threshold of the eggs during diapause in the winter period is -40°C. Sharp temperature fluctuations in March and April cause the death of 98% of the eggs.
Egg Laying
The fecundity of the female moth reaches an average of 130-350 eggs. The females lay the eggs all at once on the surface of their cocoons. The eggs are light gray.
Larva
In regions where only one generation develops, caterpillar hatching begins in early May. In areas with two generations, caterpillars hatch in late April, 3-5 days before the beginning of apple blossom, and begin feeding on the leaves. Initially, they skeletonize the leaves, and later, they consume the round leaf blades along the edges, leaving only the petioles and central veins. They can also damage the ovaries and young fruits. The caterpillars are gray with red warts and five tufts of long brown hairs. Their feeding period lasts 25-55 days depending on the area. Caterpillars of the second generation develop from July to August.
Pupation
Pupation occurs at the end of July in regions with one generation, at the beginning of July in areas with two generations, and at the beginning or mid-May in regions with three generations; in the crowns of trees, in cracks in the bark of trunks and branches. The pupae are yellow-gray, without wing coverings, placed in a transparent cocoon. The development of the summer pupae takes 7-15 days for males, 10-22 days for females; the autumn pupae develop for about 20 days. In September, moths of the second generation fly and lay eggs, which enter diapause until spring.