Isocycloseram seed treatment for reducing wireworm populations (Agriotes obscurus) (Coleoptera: Elateridae) and protecting wheat crops in British Columbia.

Abstract

Wireworms (Coleoptera: Elateridae), the larval stage of several economic click beetle species, have become major cereal crop pests in key agricultural regions of Canada and the United States. In recent trials following minimum tillage practices (Alberta), we determined that isocycloseram, the initial isoxazoline agricultural seed treatment developed, provided exceptional control of cereal crop damage, and significantly reduced neonate and resident wireworm populations of the sugarbeet wireworm, Limonius californicus (Mannerheim). Herein we evaluated isocycloseram in cultivated wheat plots (British Columbia) for control of the dusky wireworm, Agriotes obscurus L., and collectively these studies determined that isocycloseram applied at 5.0 to 7.5 g AI/100 kg seed protected crop stand and yield from these species equal to all currently registered wireworm seed-treatment insecticides (ie, neonicotinoids, diamides, and meta-diamides), and significantly reduced resident and neonate wireworms equal to levels expected from the former industry standard lindane. Abiotic and biotic conditions negatively influencing insecticide performance and ways to mitigate them were also identified. These conditions include soil fertility, moisture, and compaction, and planting after most wireworm feeding in the spring has occurred.