Description, Biology, Life Cycle, Damage, Common Names, Images
- Host plants: cauliflower, cabbage, turnip, nasturtium (Tropoeolum); more rarely red cabbage, radish, Resadaceae.
- Adult: essentially diurnal, the butterfly is active when the sun shines and the temperature is sufficiently high; otherwise, it remains under leaves or other shelter, its wings erect but with the fore wings hidden from view. Its flight is irregular.
At times, the butterflies can make mass migrations. They mate during flight, soon after emergence.
- Eggs: they are deposited in clusters of 20 to 50 on the underside of the leaves of host plants.
Embryonic development lasts 6 to 10 days.
- Larva: they first live in colonies, narrowly grouped one against the other and superficially gnaw the leaf epidermis. After the second moult, they scatter into groups of 4 to 5 individuals. They are then extremely voracious and perforate the foliage.
- Pupa: held with a belt-like grindle of silk, not in a cocoon (*) . Pupation lasts 10 to 15 days.
- 2 generations per year, sometimes 3 in meridional regions.
- The butterfly which emerges from the overwintered pupa, fly as early as the beginning of May and soon lay eggs; the caterpillars develop and then pupate in June on various supports (walls, roofs, fence posts).
- The butterflies appear in July-August and produce a second generation much more harmful than the first. The caterpillars develop in July-August and pupate in September, the pupae overwinter.
- The caterpillars eat the leaves of brassicas, often leaving only the large veins (*) . Furthemore, their frass, thinned out by the rain or dew, accumulates in the heart of the plant rendering it inedible.
- Unlike cabbage moth (Mamestra brassicae) larvae which attack the leaves of the heart of the plant, those of the large white butterfly attack the open leaves.
HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.