Attract-and-Kill Using a Moth Attractant: Potential Role in Resistance Management in Transgenic Cotton

The Australian cotton industry follows resistance management plans (RMPs) to reduce the risk of developing Bt resistance in 'Helicoverpa' moths. We are investigating the potential of "moth busting" using a plant volatile-based moth attractant (Magnet®) for attract-and-kill, targeting potentially resistant moths emerging in late season cotton. Following a pilot trial in the 2011/12 season, we conducted our first large-scale field trials in the 2012/13 season in the Upper Namoi region to determine, whether, on an area-wide basis, appropriately timed and placed applications of attract-and-kill can reduce the numbers of potentially resistant 'Helicoverpa' moths emerging and surviving in Bt cotton in late summer/early autumn. The field trials involved treating about 1500 ha of transgenic (Bt) cotton in each of two locations. Each location had replicated fields of treated and untreated cotton, and fields of pigeon peas (required as refuge crops in RMPs) as well as other 'Helicoverpa' host crops. Light trap and pheromone trap data demonstrated that catches of 'Helicoverpa' moths in cotton were suppressed during and soon after Magnet® applications, and that there appeared to be no impact of the treatments on moth populations in the refuges. The host origins of moths killed by the attract-and-kill formulation are being determined by stable carbon isotope and lipid analysis, and will be compared with those of the general moth population obtained from light and pheromone traps. Bt resistance levels are being monitored and will be compared between treated and untreated regions within the study area, and with other cotton growing regions.