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POSTERS: Postharvest pathology and mycotoxins

Efficacy of pesticides for mitigating stink bug feeding injury and associated mycotoxin contamination in field corn
Joseph Opoku - Virginia Tech Tidewater AREC. Hillary Mehl- Virginia Tech Tidewater AREC

Previous studies demonstrated associations between stink bug feeding and mycotoxins in corn and potential vectoring of mycotoxigenic Fusarium spp. by stink bugs. The objective of this study was to assess efficacy of pesticides for mitigation of stink bug-associated mycotoxin contamination. Fungicide (prothioconazole) and insecticide (bifenthrin) were applied to corn plots either individually or in combination at silking. A second experiment included prothioconazole treatment as the main plot, and subplot treatments (untreated, stink bug, Fusarium, and Fusarium + stink bug) were applied to bagged ears. Following harvest, stink bug feeding injury was visually assessed, and mycotoxins were quantified using Neogen Reveal Q+ kits. In the first experiment, prothioconazole and bifenthrin reduced kernel injury but not mycotoxins. However, there was a positive correlation between levels of stink bug feeding injury and concentrations of fumonisin and aflatoxin. In non-fungicide treated plots of the second experiment, kernels from stink bug + Fusarium treatment had higher fumonisin compared to kernels from stink bug only, Fusarium only, or non-treated corn ears (P= 0.004). However, in prothioconazole treated plots, application of stink bugs and Fusarium did not increase fumonisin (P=0.103). Results indicate both fungicide and insecticide may reduce stink bug associated mycotoxins in corn, but additional tactics are needed when contamination risk is high.