Comparing Corn Silk Fly Populations in Sweet Corn Fields and Surrounding Habitats

Picture-winged flies (Diptera: Ulidiidae), referred to as corn silk flies in Florida, are major insect pests of sweet corn produced for the fresh market in the southern region of the state.Adults of three species, Euxesta stigmatias, Euxesta eluta, and Chaetopsis massyla lay eggs on sweet corn silks, resulting in maggots feeding on developing kernels.These adults are managed with insecticide applications to prevent oviposition.However, frequent applications are needed to meet market standards because corn silk fly adults quickly reinfest treated sweet corn fields.In Spring 2021 and 2022, eight sites on commercial farms in the Everglades Agricultural Area (EAA) were sampled to determine corn silk fly adult relative abundance in a sweet corn field, a sugarcane field, and a non-crop area.For each habitat at each site, five Multilure traps baited with ammonium acetate and 1,4-dimethoxybenzene were deployed along a 245-m transect to collect adults weekly for three to four weeks.Additionally, sampling was conducted at the University of Florida, Institute of Food and Agricultural Sciences Everglades Research and Education Center, which is a research farm in the EAA.One hundred fifty-four sampling locations were selected throughout this research site following a grid pattern with interlocation distances of 90-115 m.These locations represented a mosaic of habitats similar to those sampled on commercial farms.However, unlike commercial fields, sweet corn research fields are not intensively treated with insecticides.A Multilure trap was deployed at each sampling location, and corn silk fly adults were collected weekly for four weeks.