Description, Biology, Life Cycle, Damage, Common Names, Images
Host plant : cauliflower and other brassicas.
- Fecundity: 40 to 45 eggs.
- Egg: embryonic development lasts 3 to 5 days.
- Larva: larval growth lasts 10 to 12 days then the larva pupates at the surface of the ground (for which it requires very high humidity), or overwinters inside a cocoon.
- Pupa: development lasts about 12 days.
- 3 generations overlap from May until the beginning of automn.
- The adults emerge at intervals from the end of May to the end of June (as early as the 15th May in sheltered crops). The female deposits 3, 4 or 5 times, clusters of 8 to 15 eggs on the terminal buds (*) , on the petioles of young leaves or on the inflorescences of brassicas, especially cauliflower and swede. A second flight occurs in July, a third in August; sometimes there is a partial 4th flight.
- The pupae can remain in diapause for 1 or more years.
The larvae develop at the base of the central leaves. They feed by producing saliva which digests the neighbouring plant tissue. The leaf petiole incurvates, the lamina swells, the central bud loses its structure and the central inflorescence does not form. A small protuberance ("blind cabbage" (*) ) appears in its place. If eggs are laid on older cauliflowers, the inflorescence develops irregularly and the cauliflower becomes unmarketable.
The larval attack often favours the development of fungi and bacteria which leads to rotting of the plant.
HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.