Description, Biology, Life Cycle, Damage, Common Names, Images
- Host plants: cultivated Cruciferae (cabbage, rape) or wild Cruciferae.
- Winter eggs are deposited on the underside of leaves and stems and hatch as early as February-March. The fundatrix gives rise to apterous virginoparae forming colonies which develop progressively, spreading to leaves at the heart of plants and forming compact sheaths around flower scapes.
Winged individuals emerge when the population has reached a maximum and spred infestations to new plants. Colonies are then diminished progressively by aphid-eating animals. Sexuales appear in autumn and enventually mate.
- This autoecious aphid does not migrate, remaining on cruciferous plants during its whole life-cycle. Aphid numbers reach a peak in late May, when pods form.
- Virginoparae survive during mild winters, multiplying from February onwards and giving birth to winged individuals, which may lead to early infestations.
- In case of rapid multiplication, plants may become covered entirely by aphids, honeydew and exuviae. Affected cabbage or rape grow imperfectly and wither. Central flowers curl up and become discoloured (*) . The feeding of aphids causes flower scapes to become distorted and flowers to abort (*) .
HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.