Ergot’s effect on wheat grades

Find out if you have ergot in your wheat

Find out if ergot is a grading factor in your crop before you deliver

  • To receive a grade including grading factors for a fee, submit a sample of your crop to a Canadian Grain Commission service centre
  • To receive a grade including grading factors for free during harvest, sign up to send a sample of your crop to the Canadian Grain Commission’s Harvest Sample Program

Appearance of ergot

When a plant is infected with ergot, kernels are replaced by ergot bodies or sclerotia. These ergot bodies are black or dark purple and hard. These bodies grow in place of wheat kernels, and can be almost the same size and shape as a wheat kernel. You may also see ergot bodies that are much larger than wheat kernels.

Figure 1, left to right: Ergot-infected wheat head, ergot-free wheat, ergot bodies.

Figure 1. Wheat kernels (centre) are compared to ergot bodies (right).

On the wheat head (left) in figure 1, an ergot body replaces the affected kernel as it grows, resulting in an ergot body that is similar in size and shape to the kernel it replaced.

Grading tolerances for ergot

Ergot is a grading factor in Canadian wheat. A grading factor is a physical condition of grain, which can be the result of growing conditions, handling procedures or storage practices. The grade of your grain is determined based on a sample taken to represent an entire truckload, carload, or cargo.

Grading tolerances for ergot are tight for safety and quality reasons. To receive a specific grade, a sample of wheat must be within tolerance for every grading factor. Even if a sample of wheat is within tolerance for every other grading factor, a small amount of ergot can cause the sample to be graded as the lowest grade for its class.

Grading tolerances for ergot are set based on the results of scientific research conducted by the Canadian Grain Commission and based on recommendations made to the Canadian Grain Commission by the Western Standards Committee and Eastern Standards Committee. Grading factors and tolerances for grains regulated under the Canada Grain Act are listed in the Official Grain Grading Guide.

Clean ergot out of wheat

If ergot is an issue in your wheat, having grain cleaned to remove ergot bodies may allow your crop to receive a higher grade. Research your options for seed cleaning, including types of service available and any fees charged. Having all the information before you deliver will help you make choices that work for you.

Ergot bodies are difficult to clean from wheat because the most common cleaning equipment separates foreign material, like ergot bodies, by size and shape. While some ergot bodies are larger than wheat kernels, most are similar in size and shape.

Many seed cleaning companies and some licensed primary elevators can remove ergot bodies using specialized equipment. The most common way to remove ergot bodies is by using a gravity table. Gravity tables use differences in density to remove ergot bodies from wheat. Some seed cleaning companies and licensed primary elevators may use a colour sorter. A colour sorter is a computerized piece of equipment that removes any material that differs in colour from wheat.

Ergot toxicity

Ergot is a plant disease caused by the fungus Claviceps purpurea. In an infected plant, chemicals that are toxic to both humans and animals even in small amounts are produced in the ergot bodies. This toxicity cannot be reduced through processing. Any flour or feed made from ergot-infected cereals such as wheat will still be toxic. The impact of ergot on end-use quality is of minor concern when compared with the toxicity of ergot bodies.

Conditions for ergot development

Weather is one of the main contributing factors to the development of ergot. If the weather is cool, cloudy and wet when cereals are flowering, Claviceps purpurea spores may enter the floret and begin developing into ergot bodies. At harvest, ergot bodies can fall and stick in the soil, where they can survive the winter. If the soil is wet enough in the spring, these ergot bodies can release spores that may infect new crop and weeds.

Prevent ergot

There are several strategies that you can use during harvesting, tillage and seeding to prevent ergot in your crop. For information about agronomic practices that you can follow to help prevent ergot, refer to Ergot of Cereals and Grasses from the Government of Saskatchewan.

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