(2nd Place) Insecticide seed treatment performance in onion against Delia spp.

The maggot complex consisting of Delia antiqua and Delia platura is a major constraint for producing onions across the temperate regions of North America. Current management of Delia spp. in onion relies on using an insecticide applied at planting, typically delivered as a seed treatment. Performance of existing seed treatments for Delia spp. control varies substantially among farms in New York, and these differences may be attributed to the overall abundance of the Delia spp. population complex, the proportion of each Delia spp., and the sensitivity of each Delia spp. to the insecticide seed treatments used. Anecdotally, cyromazine kills D. antiqua, but not D. platura, while spinosad kills both species. However, the lack of new chemistries and possible insecticide resistance have accelerated an effort to understand the species abundance and pest status among production regions. Our research aims to quantify the dominant Delia species in onion fields and to determine the level of protection that each insecticide has against each Delia species.