Prevalence of Mycotoxins in Late-Season Corn Ear Molds in North Dakota

Abstract

Widespread corn ear mold development in North Dakota and in other states was associated with cool, wet weather after physiological maturity in 2009. In response to concerns about possible grain mold and mycotoxin contamination in North Dakota, a survey of corn ear diseases was conducted in 2009 prior to harvest. Corn ears were collected from 94 field locations from 24 counties and were examined macroscopically and microscopically for mold identification. Mycotoxin testing was done with a screen for 17 tricothecenes using gas chromatography/mass spectrometry techniques. Cladosporium was the most commonly identified fungus with some Fusarium contaminated samples being observed. Other fungi identified include Alternaria, Penicillium, Aureobsidium, Rhizopus, Stemphylium and an unidentified non-pigmented fungus. Five mycotoxins were identified in 25 out of the 94 samples; deoxynivalenol, T-2, HT-2, zearalenone and nivalenol. Of the mycotoxin-positive samples, 88% had less than 2 ppm of any mycotoxin. Despite the growing season’s weather being favorable for corn ear mold development late in the season, observed mycotoxin levels were surprisingly low and most grain was deemed safe for use in food and feed channels. Surveys were planned in subsequent years, but late season molds did not develop in the 2010-2015 growing seasons.