Impact of hail damage during early reproductive stages on ear rot and mycotoxin contamination of maize

During the 2009 growing season in Iowa, two severe hail storms affected over 400,000 hectares of maize during early reproductive stages. Concerns were raised about increased ear rot disease and associated mycotoxin contamination. To address these concerns, samples of ears were collected within 48 hours of harvest from 57 fields damaged by hail and 25 undamaged fields. Ears were visually assessed for kernel damage and ear rot severity. After shelling, grain was ground and tested for deoxynivalenol (DON), zearalenone (ZEA) and fumonisins (FUM) using commercially available antibody-based lateral flow strip tests. Confirmation analysis on elevated samples was performed by Gas Chromatography for DON and High Pressure Liquid Chromatography for ZEA and FUM. Fusarium, Gibberella and Cladosporium ear rots were the most prevalent diseases. Hail damage to kernels increased the risk of ear rot. The most prevalent mycotoxin detected was DON (mean 2.63 ppm), followed by ZEA (mean 0.53 ppm) and FUM (mean 0.49 ppm). Levels of DON and ZEA in grain from hail damaged fields were greater than those detected in grain from undamaged fields. There was a positive relationship between ear rot severity and DON and ZEA contamination (r = 0.645, P < 0.001 and r = 0.474, P < 0.001, respectively). Levels of DON also were correlated with test weight (r = -0.38, P = 0.004) and protein (r = 0.49, P < 0.001). In the future, preharvest scouting of fields with suspected mycotoxins may be an effective strategy for targeting postharvest inspection and marketing activities.