Q What are cabbage whitefly?

A These white-winged, 2mm-long insects are invariably found in large numbers as they feed on the undersides of brassicas' leaves for much of the year. Their young, known as 'scales' are flattened, oval, immobile and also found on the undersides of the leaves. These pests produce a sticky excreta known as 'honeydew' which may coat the brassicas and also encourage black 'sooty moulds' to develop. They have several generations each summer and then overwinter as adults.

Caption: Cabbage whitefly often appear in huge numbers

Q How can I help plants affected by cabbage whitefly?

A Treat with a contact insecticide such as Bayer Natria.

Q How can I prevent cabbage whitefly?

A It’s difficult to keep these pests out, but a pop-up cage covered with fleece or fine mesh, such as Best Buy Enviromesh or Wondermesh, may do the trick.