The cotton aphid, Aphis gossypii is a pest of escalating concern in Australia. With increasing utilisation of Bt cotton and consequent reduction in insecticide applications, coupled with emerging insecticide resistance, cotton aphids appear to be more of a problem than previously. The cotton aphid also has been shown to carry, or cause, a new major problem for the Australian cotton industry, cotton bunchy top. Fundamental to the development of IPM systems for cotton aphid is the knowledge of what biological control agents are active and their relative importance.

The cotton aphid paresitoid, Lysiphlebus testaceipes released in Australia in 1984 has recently (2000) been found attacking corn aphids on sorghum in cotton areas in Australia. The paresitoid more recently (2001) has been recorded from

the cotton aphid in Australia. However no systematic survey to determine its abundance and importance has been carried out. This parasitoid was recently rated by USA cotton IPM specialists as the most important paresitoid of all those attacking pest insects in cotton in the USA.

Two other aphids (the green peach aphid and the cowpea aphid) also occur in cotton. Nothing is known about how the natural enemies of the different aphids interact and influence the biological control of each aphid species.

Trap crops are an important part of cotton production. Other aphids in trap crops including the cowpea aphid, soybean aphid and corn aphid may also play an important role in providing a refuge for biocontrol agents of aphids in cotton. Trap crops may be able to be manipulated and managed to provide beneficials for aphid control in cotton.

Aphid parasitoids in other agroecosystems have provided effective biological control of aphids (eg. Iuceme in Australia and wheat in South America). The new parasitoid, L testaciepes may be able to provide effective biocontrol of cotton aphid in Australian cotton.