The cotton aphid, (Aphis gossypii), is a pest of increasing concern in Australian cotton. Cotton aphid is considered a pest due to yield reduction if a heavy and persistent infestation occurs. Cotton aphid honeydew is frequently a problem late in the growing season due to honeydew contamination of boll lint. Further cotton aphid is a vector of cotton bunchy top (CBT), a disease of cotton that under certain conditions, can cause serious yield loss.

Cotton aphid is typically managed by using insecticides, however over time cotton aphids have developed resistance to insecticides used against it, most recently to neonicotinoids (Confidor).

A more sustainable approach to aphid management would be to use beneficial arthropods like ladybugs, hoverflies and parasitoids to reduce aphid populations. Unfortunately, little is known about the biology and ecology of these natural enemies, so it is difficult to include their presence in cotton fields into pest management practices.

This project focussed on understanding more about the biology and ecology of the aphid parasitoid Lysiphlebus testaceipes. This parasitoid wasp was introduced to Australia in 1982, but wasn't detected in large numbers in cotton districts until 1997. Overseas the parasitoid is considered an important biological agent, but in Australia there is limited information on its importance as a natural enemy of cotton aphid.