Potential Use of Visual Mold Ratings to Predict Mycotoxin Contamination of Grain Sorghum

The suggested association between zearalenone contamination and Fusarium grain mold, along with documented cases of zearalenone and deoxynivalenol contamination in sorghum [Sorghum bicolor (L.) Moench], prompted an investigation into a determination if field scouting could be used to predict contamination level. Several sorghum hybrids were examined for bird damage and visible grain mold prior to harvest at seven locations in 1986 and 1987. Zearalenone and deoxynivalenol levels were analyzed in the harvested samples. Bird damage, Fusarium grain mold, zearalenone, and deoxynivalenol were detected in 68, 87, 67, and 88% of all samples, respectively. There appeared to be no correlation between bird damage and mycotoxin levels; however, highly significant correlation coefficients of 0.38** and 0.39** were found between grain mold and zearalenone and deoxynivalenol levels, respectively. Of the 13% of the samples with no visible grain mold, all were contaminated with one or both of these mycotoxins. With 96% of the samples showing signs of mold and later revealing detectable levels of zearalenone or deoxynivalenol, it would appear that visible grain mold can indicate possible mycotoxin contamination; however, absence of any grain mold does not necessarily assure the grain is free from contamination.