Biology

• Development cycle : includes 4 development phases: egg, larva or caterpillar, pupa or chrysalis, and butterfly.
  • the eggs are deposited on the surfaces of the leaves.
  • Subsequently, they hatch and give birth to caterpillars equipped with powerful mandibles which allow them to constantly consume plants, especially leaves. The caterpillars, greenish white in color, have long white bristles on their body. They moult several times, before pupation or chrysalization.
  • The pupae, on which we can clearly see the sheaths of the legs and wings as well as the abdominal segmentation, are reddish-brown in color.
  • The adults are butterflies with 2 pairs of wings and whose wingspan varies from 15 to 25 mm in wingspan. They are characterized by a greyish yellow color and the presence of a brown triangular spot located at the tip of the forewings.
• Dispersal : Caterpillars are mobile and move easily from leaf to leaf like adults, who do so more easily.

Protection

• Produce the seedlings in an nursery insect-proof .
• Check the sanitary quality of the plants before and during their introduction into the crop or shelter.
• Install  canvases  insect-proof in nurseries and at shelter openings when weather conditions allow.
• Install pheromone traps outside the shelter. (1)
• Favor natural enemies in field crops or under open shelters (2).
• Use biopesticides (3).
• Reasoning about  chemical protection.

(1) Selective trapping with pheromones can be used to limit the parasitic pressure of this insect. The monitoring of the traps will make it possible to follow the evolution of the population of adult moths and therefore to more precisely position the Bt-based treatments.

(2) Certain parasitoid auxiliaries (Hymenoptera and Tachineus fly) allow the larvae of to be controlled naturally Sodoptera eridania .

(3) The use of a product based on the insecticidal bacterium Bacillus thuringiensis (Bt) makes it possible to kill the young larvae of moths which ingest the product by consuming the cabbage leaves. As the sun inactivates Bt-based formulations and the young caterpillars are especially active at night, applications at the end of the day will be preferred to ensure good treatment efficiency. Irrigation by sprinkling the plot should not be started after the treatment, which would otherwise risk being completely washed out.