Post-harvest crop destruction effects on picture-winged fly (Diptera: Ulidiidae) emergence

Abstract

Sweet corn grown in Florida that is not well protected by insecticides often becomes heavily infested by maggots of picture-winged flies (Diptera: Ulidiidae). Additionally, after marketable ears are harvested, remaining ears are left unprotected and can be exploited by female flies. Larvae leave the ears to pupate in the soil. Occasionally, crop residue removal is delayed, sometimes for several weeks. Sweet corn plots were established in Fall 2015 and Spring 2016 to determine how various crop destruction techniques might impact the successful completion of the corn-infesting picture-winged fly life cycle. After harvest maturity, untreated sweet corn plots were partially mowed, disked once, disked twice, or left standing in the fall. In the spring, plots were partially plowed, disked twice, or left standing. Emergence cages were erected over the soil to intercept newly emerging adults. In the fall, crop destruction did not reduce adult emergence compared with the standing corn plots. In the spring, both plowing and disking significantly reduced adult fly emergence from the soil. The species complex emerging from the soil in the spring after crop destruction differed from the adult species complex present earlier during the spring corn's reproductive stages. Seasonal differences may have contributed to this inconsistency. Crop destruction does not initially appear to be a reliable method to reduce 1st generation adult fly emergence from ears post-harvest, highlighting the importance of timely crop destruction to deny females an unprotected host in which to oviposit.