Following the deregistration of lindane, several neonicotinoid insecticides have been registered as seed treatments for controlling wireworms in cereal crops. Unlike lindane, which did both, neonicotinoids provide crop protection but do not reduce wireworm populations. Hence populations of various economic species are growing in key wheat production areas of the United States and Canada, and there is a need for novel seed treatments that match the efficacy of lindane. Herein we evaluated broflanilide, a novel GABA-gated Cl- channel allosteric modulator that differs from the cyclodienes (e.g., lindane) in that it binds to a unique site in the GABA receptor. As such, broflanilide confers a new mode of insecticidal action (Group 30 MOA), and is the first meta-diamide insecticide developed. When evaluated in field trials over 7 yr at various rates, broflanilide at 5.0 g [AI]/100 kg wheat seed was as effective at protecting wheat stand from wireworm (Agriotes obscurus) injury as the current industry standard thiamethoxam at 20-30 g [AI]/100 kg seed. In addition, broflanilide at 5.0 g reduced neonate wireworms (produced from eggs laid in established wheat during the growing season) and resident wireworms (in the field at time of planting) by 73.1 and 81.1%, respectively, which is comparable to that reported for the previous industry standard lindane (75.3 and 57.6%, respectively). These studies show that broflanilide at 5.0 g [AI] will provide consistent wheat stand protection (equal to thiamethoxam at 20-30 g [AI]), and A. obscurus wireworm population reduction (equal to lindane at 59 g [AI]), and will do so at far lower dosages per hectare.
Keywords: broflanilide; meta-diamide; seed treatment; wheat; wireworm.
© Her Majesty the Queen in Right of Canada, as represented by the Minister of Agriculture, 2021.