There have been multiple reports of ergot in wheat last week coming from north central Kansas. To date the information suggests that ergot was detected in loads of grain in Jewell and Republic counties. The harvest is just getting started in this area and it is possible that more loads of grain will be found to be positive for this fungal disease.
Ergot is a fungal disease that infects the wheat and other grasses during the flowering stages of growth. The fungus colonizes the developing wheat kernels, resulting in large dark-colored fungal survival structures called “sclerotia.” The fungus produces a toxin that can cause serious health problems for humans and animals. Loads of grain containing ergot may receive price discounts or even be rejected at the point of delivery.
The fungus that causes ergot can survive between growing seasons as a sclerotia. These sclerotia germinate in the spring, resulting in specialized spore-producing structures. The spores are then moved by wind to nearby wheat fields. The disease is favored by cool wet conditions during these critical growth stages, and it appears that the heavy rains in north central Kansas created conditions favorable for ergot to infection some late-flowering fields.
Ergot is also able to infect many types of wild grasses and cereal crops including rye, barley, and wheat. Rye and barley are generally considered to be more susceptible to ergot than wheat. In fact, some of preliminary reports of ergot contamination are associated with fields that had a feral rye problem. This suggests that the rye may be contributing to the levels of ergot observed in some loads of wheat grain.
The ergot sclerotia can be removed from grain with grain cleaning equipment. Cleaning large volumes of grain after harvest may be impractical, but it may be possible to remove many of the sclerotia by turning up the air on the combine during harvest. Grain from fields infested with ergot should not be saved for seed because of the risk of sowing the fungus along with the wheat. If it is necessary to save the grain for seed, it would be a good idea to have the grain cleaned to remove as many sclerotia as possible.
Crop rotation is best means of avoiding future problems with ergot. Fields infested with ergot sclerotia should not be planted back to wheat this fall. The beneficial effect of crop rotation will be reduced, however, if feral rye and other grassy weeds are allowed to head within or around the affected fields. Mowing the grass in ditches surrounding the fields in question will reduce the risk that fungus could also survive in these areas.