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Association between brown marmorated stink bug (Halymorpha halys) injury and mycotoxin contamination in Virginia field corn
H. L. MEHL (1), D. A. Herbert (1). (1) Virginia Tech Tidewater AREC, Suffolk, VA, U.S.A.

During the 2013 Virginia Soybean Insect Pest Survey, large populations of brown marmorated stink bug (BMSB), a recent invasive from Asia, were observed on edges of corn fields. Feeding by BMSB in these fields damaged developing kernels. To determine if BMSB damage increases mycotoxins in Virginia field-corn, ears were collected from edges and interiors of 8 corn fields; kernels were evaluated for BMSB injury, fungal infection, and mycotoxin contamination. Proportions of BMSB-injured kernels were higher from ears collected at the edge (23%) compared to the interior of fields (2%). <i>Fusarium verticillioides</i> was the fungus most frequently isolated from kernels<i>. </i>Other fungi included <i>F. graminearum</i>, <i>Aspergillus flavus</i>, <i>A. niger</i>, and <i>Penicillium </i>spp. Kernels from field edges had greater levels of <i>Fusarium</i> infection than kernels from the interior (<i>P</i>=0.02). Fumonisin, zearalenone, deoxynivalenol, and aflatoxin were all detected, but only fumonisin exceeded FDA advisory levels. Concentrations of all four mycotoxins varied among locations, but fumonisin was consistently higher in kernels collected from field edges (4 to 37 ppm) compared to interiors (<2 ppm). Fumonisin levels were positively correlated with <i>Fusarium </i>infection (r2=0.33, <i>P</i><0.0001) and BMSB damage (r2=0.26, <i>P</i>=0.0004). BMSB-injured kernels separated from uninjured kernels had over 100 ppm fumonisin. BMSB damage at the edge of corn fields has the potential to increase overall mycotoxin levels in the crop.

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