D3265: Risk factors influencing seedcorn maggot occurrence in Quebec field crops

The seedcorn maggot, Delia platura (Meigen) (Diptera: Anthomyiidae), is a cosmopolitan, polyphagous pest that attacks many field crops and vegetable plants. The larva feeds on the underground parts of young plants (seeds, roots, stems, cotyledons), which can lead to stunted growth and even death of plants. Although it is a sporadic pest in corn and soybeans in Quebec, high infestation can cause total loss of seedlings over several hectares. In order to elucidate the mechanisms of D. platura attraction, Boosted Regression Trees (BRT) were used to analyze D. platura larval capture data collected as part of the soil dwelling pest scouting done by the Field Crop Pest Warning Network since 2011. This analysis revealed that the most important risk factors explaining the presence of D. platura larvae in Quebec fields were region, crops in the previous three years, seeding date, weed pressure and type of tillage. Scouting in at risk fields currently underway to validate these risk factors.