Bayer CropScience - Pestspotter - Mealy cabbage aphid

Pest: Mealy cabbage aphid

Identification
The adults are greyish / green, with a body covering of greyish white mealy wax. These aphids form large colonies on stems and flowering shoots of individual plants.

Symptoms
This aphid is a major pest of brassica crops and causes serious feeding damage leaving plants weakened and distorted.

Life cycle
This aphid is restricted to members of the mustard oil containing herbaceous Brassicaceae (Cruciferae), throughout its life cycle. The shiny black eggs are laid on the stems and leaves of cruciferous crops. These hatch in early spring producing young which feed on the leaves and shoots. Winged forms produced in May - June migrate to newly planted brassica crops, where numbers can increase rapidly. In recent years, more of the population has overwintered as mobile stages rather than eggs.

Importance

This aphid is a major pest of broccoli, cabbage, cauliflower, kohl rabi, radish and swede. In oilseed rape damage is often restricted to individual plants rather than whole crops. Damage can include loss of pods and individual plants particularly in spring rape where populations can build up quickly in warmer conditions.

In vegetable crops it causes serius feeding damage, leaving plants weakened and stunted. Heavily infested seedlings and young plants can wilt and die. Less serious distortion and fouling of leaf surfaces adversely affects marketability.

It has been estimated that this pest can also transmit up to 20 different plant viruses, of which cauliflower mosaic and turnip mosaic virus are the most important..

Threshold

13 % of winter oilseed rape or 4 % of spring rape plants infested before petal fall.

On Brassicas