Aphid management in canola crops

Aphids are common pests of canola in Western Australia. They suck sap from plants and can be found massed on growing points or lower leaves of canola, depending on the aphid species. During growing seasons preceded by above average rainfall in March and April, aphids can arrive in crops in large numbers early in the season. Cold weather and heavy rainfall during the growing season can help to suppress aphid numbers. This document focuses on control measures against aphid feeding damage caused by sap removal and associated effects, but does not cover management of the viruses spread by aphids.

Description

Three aphid species commonly attack canola in Western Australia:

  • Turnip aphid

Turnip aphid on canola flowering spike

Turnip aphid on canola flowering spike
  • Cabbage aphid

Cabbage aphid on canola flowering spike

Cabbage aphid on canola flowering spike
  • Green peach aphid

Green peach aphid on underside of canola leaf

Green peach aphid on underside of canola leaf

Distinguishing features of the three species of aphids found attacking canola in WA

Table 1 Distinguishing features of aphids attacking canola
- Turnip aphid Cabbage aphid Green peach aphid
Length of adult (mm) 1.4-2.4 1.6-2.8 1.2-2.3
Abdomen colour Greyish to mid green Greyish to mid green Shiny yellow to mid green to pink or red
Other features Body often has a light waxy covering, dark bars on abdomen Body covered with a dense white mealy wax Black patch on abdomen of winged adults. Wingless forms uniform in colour
Colony habit Dense colonies, usually around growing tips and flowering spikes Dense colonies usually seen on flowering spikes Mostly found on the underside of lower leaves. Sparse colonies may occur with turnip or cabbage aphids
Abundance on canola Usually common and abundant; depending on season Common and abundant on canola Common but seldom builds up to large colonies
Alternative hosts Wild radish, wild turnip and self sown canola Wild radish, wild turnip and self sown canola Wild radish, wild turnip, and self sown canola, lupins, capeweed

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Page last updated: Tuesday, 9 May 2017 - 9:19am