Dry weather no reason for farmers to stop worrying about mycotoxins

Many mycotoxins are associated with wet weather, but grain-based aflatoxins and other fungal diseases can thrive in hot, dry conditions

Growing conditions across much of Western Canada have been hot and dry this year, especially in southern and central growing regions during late July and August.

But that doesn’t necessarily mean that the grain harvested this fall will be free of deoxynivalenol (DON) or other grain-borne mycotoxins.

“Obviously, it’s still pretty early so we haven’t done much testing yet but there definitely have been some changes to weather patterns this year, which could influence the mycotoxins that we’re seeing,” said Alexandra Weaver, an expert on grain mycotoxins with Alltech Canada.

“Certainly there has been some warmer weather and some drier weather so that can definitely influence the occurrence of moulds and the types of mycotoxins that we see.”

“There is still a risk. It could just be a very different type of risk this year.”

Weaver recently presented information on mycotoxin risk factors during a web-based event hosted by Alltech Canada.

Although many grain-based mycotoxins such as DON develop during wet growing conditions or periods of prolonged high humidity and moisture, Weaver said any conditions that cause plant stress, including drought, hail or wind, can be conducive to mould growth and the presence of mycotoxins.

Grain-based aflatoxins, for example, can occur during dry conditions. Other fungal species that can cause toxicity in grain can also thrive during hot, dry conditions, when crops become drought stressed.

Weaver also warned about the growth of moulds and toxins during grain storage.

Ideally, grain that goes into the bin should be in good condition and moisture levels should be at or below recommended levels.

High grain temperatures are more conducive to grain spoilage and the development of moulds and mycotoxins.

Weaver said growers should be aware of potential mycotoxin risks in grain crops, even when conditions are warm and dry.

Elevated mycotoxin levels in feed grains can significantly impact animal health in beef and dairy herds and can have potentially harmful effects on human health.

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