OMAFRA field crop specialists in collaboration with Grain Farmers of Ontario (GFO) and members of the Ontario Agri-Business Association (OABA) have completed the annual Ontario corn ear mould and DON mycotoxin survey. Corn ear moulds such as Gibberella and their corresponding mycotoxins occur every year in Ontario. These mycotoxins, particularly deoxynivalenol (DON, also referred to as vomitoxin) are produced primarily by Gibberella/Fusarium ear moulds and can be disruptive when fed to livestock, especially hogs. The 2021 survey found 89% of samples tested low (<2.00 parts per million (ppm)) for DON which is in line with long term survey averages.
Methods
From September 21 to October 2, 2021, 205 ear corn samples were randomly collected from across the province. Five consecutive ears were collected from four random locations throughout a field and placed into high temperature driers (80°C) as soon as possible after collection. Pictures were taken to document moulds and insect and bird feeding damage (Fig. 1). Dry ears were shelled and coarse ground and mixed for sub-sampling consistency. Sub samples were collected and finely ground for DON analysis by quantitative ELISA analysis at the University of Guelph Ridgetown Campus mycotoxin lab.
Results
Results for the 2021 survey are presented in Table 1. Visual mould and DON concentrations were in line with long term survey averages (Table 2). While ear moulds were certainly evident in some samples, severity was generally low with infections often appearing to be in very early stages (e.g. light mycelium growth between tip kernels). Many also displayed no symptoms, and only two samples tested over 5 ppm. Insect feeding was low as in recent surveys, but where present was often associated with visual ear mould. Other mouldy samples with no ear damage were observed where weather and hybrid susceptibility were likely factors.
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