Use of a plant-volatile moth attractant in resistance management for transgenic cotton

Abstract

We have recently registered a product called Magnet®, for attract-and-kill of adults of Helicoverpa armigera and H. punctigera in Australian cotton. It consists of a mixture of six synthetic (nature-equivalent) plant volatile chemicals, with sucrose as a feeding stimulant. Farmers can add any one of three insecticides. When applied to cotton crops, Magnet® with insecticide is capable of attracting and killing large numbers of moths. It was developed as a component for IPM in conventional (non-Bt) cotton, but this now occupies a very small proportion of Australian cotton acreage, which is dominated by transgenic Bt (Bollgard II ®) cotton. Recent trends in the frequency of resistant alleles for the two Cry toxins in Bollgard II ® suggest that additional tools may be needed for inclusion in future Resistance Management Plans, either to supplement existing measures or to replace onerous requirements such as cultivation to destroy overwintering pupae. In this presentation we will describe experiments aimed at enhancing the productivity of refuges which are used to generate unselected moths by application of Magnet® without insecticide, or (by including insecticide) killing moths emerging from late season cotton, or emerging in spring from fields which grew cotton in the previous summer.