Insecta, Lepidoptera, Cossidae .
Description, Biology, Life Cycle, Damage, Common Names, Images
- This pest is associated with asparagus in the south of France.
- Adult: it does not feed, its life span is extremely brief, 5 to 6 days maximum. Nocturnal activity only. The eggs are deposited in clusters of about 40 on the stem collar, just under the ground surface; several females can lay on the same stem.
- Fecundity: about a hundred eggs.
- Egg: embryonic development lasts 3 to 4 weeks.
- Larva: at hatching they are grouped in a silken shelter, they then move down into the ground in groups and penetrate, either the underground part of the stem at a depth of between 5 to 10 cm, or the bud. This activity lasts 1 to 4 days according to the conditions. Having eaten the inside of these parts, they attack the root system, avoiding the epidermis, except when changing root; they then disperse a little. In autumn, they spin flat and oval cocoons, at depths varying from 5 to 50 cm and hibernate in a state of diapause.
- Pupa: development lasts 3 to 5 weeks.
- Annual cycle for most individuals.
- The larvae which hibernate in the ground return near to the surface from the end of April to the beginning of June. They then spin their pupal cocoons, vertically orientated and localised principally in the harvest mound. The flight period varies from the end of May to the beginning of July for the coastal regions, from mid-June to the end of July for the interior.
- The summer activity of caterpillars, which corresponds to their injurious period, lasts a month to a month and a half.
The larva attacks the root system, feeds on the buds and hollows out the roots (*) . This leads to the disappearance of plants which dry up in the course of summer; young plantations are particularly vulnerable.
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