Bluegreen and cowpea aphids are being found in the south
- Coomalbidgup
- Condingup
- Esperance
- Wittenoom Hills
Research scientist Emma Pearse (DPIRD) has reported finding cowpea aphids in a faba bean crop near Coomalbidgup. Emma also reported finding bluegreen aphids on capeweed near Esperance.
Research scientist King yin Lui (DPIRD) found cowpea aphids in a faba bean crop near Condingup while doing surveillance.
Quenten Knight (Agronomy Focus) reports finding cow pea aphids on volunteer vetch in a wheat crop near Wittenoom Hills. The vetch is stressed from a pre-emergent application of Callisto® herbicide.
Cowpea aphids and bluegreen aphids are a common pest of legume crops.
Cowpea aphids are usually easily spotted by their black colour and dense clusters on a few plant growing points. On close inspection with a magnifying lens their black and white legs are also a good identification feature.
The bluegreen aphid can measure up to 3mm long. They are oval shaped, with long legs and antennae. They have two large cornicles that extend beyond the base of the abdomen. Both the winged and wingless forms are a matte bluish-green colour. Nymphs are similar to adults but are smaller in size.
Aphids can damage lupin crops through both feeding damage and virus transmission (cucumber mosaic virus and bean yellow mosaic virus). The degree of feeding damage depends on the varietal susceptibility, the growth stage of the crop, the percentage of plants infested and the duration of the infestation.
The spray threshold for control of aphids on lupins is for more than 30% of flowering spikes to have 30 or more aphids. Consideration should also be given to potential crop yield.
For a list of insecticides registered for use on aphids see the department’s 2019 Winter/Spring Insecticide Guide.
For more information refer to DPIRD’s Identification of aphids in lupin crops and Management of aphids in Western Australian lupin crops pages.
To read previous aphid articles and reported aphid activity in WA this season refer to DPIRD’s 2020 PestFax Issue 5 article Aphid activity update and 2020 PestFax Issue 4 article Aphids are active.
For more information contact Svetlana Micic, Research scientist, Albany on +61 (0)8 9892 8591 or Alan Lord, Technical officer, South Perth on +61 (0)8 9368 3758.
Article author: Cindy Webster (DPIRD Narrogin).