New Strategies for Corn Silk Fly Management
The fly pest commonly referred to as corn silk fly (Euxesta stigmatis) deposits eggs into the silks of sweet corn ear tips. Larvae emerge and feed down the silk into the cob tip, rendering the ears unmarketable. Larvae pupate in the soil near the plant, and overall development time (egg to adult) can range from three to five weeks.
Since this pest affects the $122 million Florida sweet corn market, research at the Everglades Research and Education Center (EREC) in Belle Glade is examining management practices. Current insecticides such as chlorpyrifos, methyl parathion, methomyl, cyfluthrin, and cyhalothrin kill more than 90 percent of the population on contact, but mortality drops below 25 percent within 72 hours after application. Consequently, efforts have been made to examine plant resistance as a mechanism to reduce corn silk fly damage.
Field trials at EREC indicated that corn varieties containing specific lipids in the plant surface or maysin in corn silk had less fly damage than other cultivars. Breeding efforts have resulted in the development of both a field corn and a shrunken 2 sweet corn with elevated maysin levels which have both been publicly released. These varieties may well help protect against armyworm and earworm, in addition to corn silk fly. (Citrus & Vegetable Magazine, November, 2003).
