Malacosoma neustrium Linnaeus - Lackey Moth.

Systematic position.

Class Insecta, order Lepidoptera, family Lasiocampidae, genus Malacosoma. The subspecies M. testaceum Motsch. is recognized in the Far East.


Malacosoma neustria Linnaeus.
European Lackey Moth.

Biological group.

Polyphagous pest of fruit crops and forest trees.

Morphology and biology.

Wingspan 30-35 mm in males, 40-45 mm in females. Head, thorax and abdomen have the same color as background of wings. Forewings pale yellow, ocherous or light brown, with wide, darker cross strip bordered by light lines. Hind wings monochrome, sometimes with wide band. Females darker than males. Fertility 40-400, 125 eggs on average. Females lay eggs at night; the eggs are gathered in a wide, spirally twisted ring on thin, one-year-old shoots. Eggs oval, dirty gray. Caterpillars hatch at the end of April or beginning of May right before blooming of apple, pear, and oak, 3-7 days after the daily average temperature reaches 11°C. Caterpillars are grayish blue with longitudinal orange stripes dorsally and laterally and with velvety black spots laterally, covered with long, hair-like setae. At first, caterpillars live in communities on sunny sides of trunks or in forks of skeletal branches. After occurrence of first leaves, they move to active feeding, eating around edges of leaves. They eat mainly at night, concealing themselves in large, silky nests in the afternoon. After 3rd molt, they pass into a solitary mode of life. Pupation occurs at the end of May in southern Ukraine, in June in the North, in dense, cigar-shaped cocoons inside cracks of bark, in hollows, rolled leaves, and (during mass outbreaks) on high grassy plants. Pupae fusiform, almost black, with violet tinge. Development of pupae lasts 30 days at temperatures of 17°C, 20 days at 20°C, and about 14 days at 23°C; the upper temperature threshold for development is 35°C. Winter-diapausing eggs winter during mature caterpillar stage inside egg case.


Occurs in Western Europe, Asia Minor, China, Korea, Japan, the Baltic States, Byelorussia, Ukraine, Moldova, Transcaucasia, northwestern Kazakhstan, and Central Asia. In Russia, it is distributed throughout the European part, northward to St. Petersburg and Yekaterinburg, in southern Siberia and in the Far East, including Sakhalin and Kunashir.


Everywhere monovoltine. Moth flight begins in mid-June in southern Ukraine and at the end of June in the forest-steppe zone; mass flight occurs in July. Moths emerge in the evenings; males appear earlier than females. Imagoes do not eat. Female search for mates and copulation occur the 1st or 2nd night after emergence. Climatic and meteorological conditions in the spring are critical, limiting Lackey Moth numbers. Young caterpillars eating buds do not endure dry air and sharp fluctuations of temperature well. Mixed diet consisting of young leaves and (beginning in the 3rd instar) mature leaves raises caterpillars. viability. Degree days for their development total 140°C; the lower temperature threshold for caterpillar and pupae development is +12.2-12.5°C. Mature caterpillars inside egg cases endure frosts as cold as -39°C in northern areas. They are vulnerable to bacterial and viral diseases; the latter in combination with adverse weather are often the cause of decreases in pest outbreaks.

Economic significance.

Polyphagous caterpillars damage all rosaceous fruit and stone-fruit cultures in gardens and parks, especially apple and plum, and also forest species, such as oak, elm, birch, willow etc., particularly oak. They are found on black currant and raspberry; compelled feeding is reported on vegetable cultures, such as potato, soya, cabbage, and carrots. Control measures include insecticide spraying against hatching caterpillars before flowering of fruit crops and cutting and burning of branches bearing egg batches in orchards.

Related references.

Chistyakov Yu.A. 1988. Family Lasiocampidae. In: Kirpichnikova, V.A. & Ler, P.A., eds. Butterflies - pests of the Far Eastern agriculture. Keys. Vladivostok: DVO AN SSSR, p. 153-165 (in Russian).
Kuznetsov V.I. 1999. Lasiocampidae. In: Kuznetsov V.I., ed. Insects and mites - pests of agricultural plants. V. 3(2). Lepidoptera. St.Petersburg: Nauka: 185-200 (in Russian).
Nekrutenko Yu.P. 1974. Lasiocampidae. In: Vasil'ev V.P., ed. Pests of agricultural crops and forest plantations. V.2. Arthropods. Kiev: Urozhai: 354-357 (in Russian).
Vasil'ev V.P., Livshits I.Z. 1984. Pests of fruit crops. Moscow: Kolos, 399 p. (in Russian).
Prokof'ev M.A. 1987. Siberian orchards protection against pests. Moscow: Rossel'khozizdat, 239 p. (in Russian).

© Grichanov I.Ya., Ovsyannikova E.I.


Web design —
Kelnik studios