Description, Biology, Life Cycle, Damage, Common Names, Images
- Host plants: rape, cabbage, turnip and radish.
- Adult: Females outnumber males by 3 to 2. Fecundity: 25 to 30 eggs. When the weather is unsuitable, they retreat to the lower part of the plants. Longevity: males, 1 to 2 days, females, 4 to 9 days.
- Eggs: time until hatching, 4 days.
- Larva: 9 to 15 days; 3 instars.
- Pupa: 7 to 35 days.
- 3 to 4 generations in northern France and in Sweden, 5 to 6 in Germany. Duration of 1st and 2nd flight period: 10 days; of 3rd: 15 days. The 1st generation develops on the pods of winter rape, the 3rd on spring rape, and the 2nd can develop on either.
- The adults emerge on warm, sunny, calm mornings from mid-April onwards in the Paris area. Mating and egg-laying occur on the same day.
- The larva feeds on the internal wall of the pod valve (or on the seeds) by discharging saliva (*) . In mid-May, they drop to the ground, bury themselves and form cocoons. Some will pupate, others may undergo diapause for 1 to 4 years.
Found especially at the edges of fields. Due to larva feeding, which causes swellings, valve deformation, precocious yellowing and bursting of pods, the seeds fall out (*) .
HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.