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Fumonisin levels in corn from the Texas High Plains as influenced by harvest date and kernel damage

Madison Cartwright: Texas A&M University

<div>In 2017, abnormally high levels of fumonisin were reported in corn in the Texas High Plains. This issue followed periods of above average humidity and below average temperatures that persisted throughout the season. Stalks (n=100) were randomly flagged in a field planted to the hybrid ‘DKC62-08’. Ears were collected on 25-Sept and from adjacent plants on 2-Oct and 13-Oct. Sampling dates were prior to, during, and after a period of cool, wet weather. Incidence of Fusarium ear rot was <5%. After shelling, kernels from five ears were combined, ground, passed through a 20-mesh sieve and assayed with QuickScan Fumonisin Test Kits (Envirologix, Portland, ME). Fumonisin levels varied by date ranging from 1.6 to 31.0 (avg. 9.3 ± 9.0), 0.0 to 7.2 (avg. 4.5 ± 2.4) and 0.0 to 14.0 (avg. 5.8 ± 4.8) ppm for the three sampling dates, respectively. Kernels from bulk samples collected on 13-Oct were scored for damage, placed into one of four categories, ground and sieved. Fumonisin levels were determined for three 20 g sub-samples from each category. Concentrations were lowest for healthy kernels and increased as damage became more severe (R<sup>2</sup>=0.945; <em>P</em><0.05). These results support previous findings regarding the positive relationship between kernel damage and fumonisins; however, additional information on the impact of weather conditions prior to harvest on accumulation of the toxin is needed. Furthermore, the effect of the host plant genetics was not addressed in this study.</div>