Insecta, Lepidoptera, Cossidae .
Description, Biology, Life Cycle, Damage, Common Names, Images
- The caterpillar develops in the trunks of numerous fruit-trees: apple, cherry, pear, plum, olive and other deciduous trees such as sweet chestnut, elm (Ulmus), oak (Quercus), poplar (Populus), chestnut (Aesculus), lime (Tilia), maple (Acer).
- Adult: The moth flies at dusk and at night, at the beginning of summer. The female, due to a powerful oviscapt, inserts her eggs in clusters in the bark crevices. Average fecundity: 500 eggs.
- Egg: embryonic development lasts 12 to 15 days.
- Larva: the caterpillar lives in galleries which it bores under the bark, then in the wood of the host tree. It ejects a reddish granular mass formed of sawdust and frass mixed with silk which accumulates at the foot of the tree. At the end of its development, it builds a cocoon out of wood particles and pupates (*) .
- The pupal stage lasts about 1 month. The adult emerges, often trailing behind itself the exuvia which then remains stuck in the bark.
- The cycle of the goat moth takes at least 2 years.
- The moths appear from the end of June to mid-August. The young caterpillars which emerge from the eggs form galleries under the bark (*) then, the following spring, penetrate the wood and bore slightly ascending galleries. They stay in the gallery the next winter and pupate in spring.
The very smelly "worm-dust" signals the attack. There are usually several caterpillars in the same trunk. The caterpillars penetrate deep into the wood and can even drill into the heartwood. Certain trees, such as elm, are extremely resistant. Fruit trees, particularly apple and cherry, are more sensitive, dying rapidly (*) . In orchards, the goat-moth generally attacks old infirmt or wounded trees in which the sap moves poorly.
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