Efficacy of new insecticides for management of Helicoverpa spp. (Lepidoptera: Noctuidae) in Australian grain crops

Abstract

Insecticide resistance in Helicoverpa armigera (Hübner) has led to the reduced efficacy of some older insecticide groups (pyrethroids and carbamates) and serious crop losses. Eight small-plot experiments were conducted to evaluate new insecticides for the management of H. armigera in grain crops. Several products showed efficacy equivalent to or better than the commercial standard, thiodicarb. Indoxacarb and spinosad at rates 50% or less of the registered rates for cotton were consistently superior to other tested products across the range of crops treated and provided residual protection for up to 14 d. The insect growth regulator compound, methoxyfenozide, was slower acting than other products tested, but demonstrated potential for H. armigera management. Pyridalyl performed well and warrants further evaluation in grain crops. We discuss the positioning of new compounds in an Insecticide Resistance Management Strategy (IRMS) in relation to a farming system that incorporates both grain and cotton crops. Use guidelines are recommended for indoxacarb, the first new compound to be registered in selected grain crops and cotton in Australia. These guidelines include restricted-use periods and limits on the number of applications per crop. It is anticipated that additional new compounds will be registered in grain crops, leading to the reduced selection pressure on the limited number of efficacious products. Coordinated insecticide use across farming systems and compatibility with developing integrated pest management programs should be fundamental considerations for the future IRMS.

Abundance and mortality of overwintering pupae of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) on the Darling Downs, Queensland, Australia

“…In some grain crops, new and more efficacious insecticides have been registered against Helicoverpa spp. (Murray et al 2005;Franzmann 2006), leading to further reductions in the numbers of survivors in insecticide-treated crops. Some of these products, e.g.…”

First results on synchrony between seasonal pattern of pheromone trap captures of cotton bollworm, Helicoverpa armigera and appearance of freshly emerged larvae on developing cobs of corn hybrids

“…To clarify this question is of special importance, because H. armigera larvae bore soon inside the cob of corn, so only eggs and freshly emerged larvae can be reached at sprayings by the applied pesticide. What gives even more special importance to this issue is that because of the uncertainty of optimal timing, farmers heavily use pesticides against H. armigera, which resulted in the appearance of pesticide-resistant (or even cross-resistant) populations (see e.g., Murray et al 2005;Ramasubramanian and Regupathy 2004). In a laboratory experiment, resistance against Cry1Ac delta-endotoxin of Bacillus thuringiensis was also reported (Akhurst et al 2003).…”

Heliothis virescens and Bt cotton in the United States

“…It is also necessary to emphasize threatened most of the animal kingdom but apparently also part of the plant kingdom. Current applications of chemicals to control TBW have been replaced with more specific insecticides that are applied at rates of only a few grams per hectare, 6,7 showing the great progress toward efficient control of this pest.…”