Scouting for Ergot
With the small grain crop approaching maturity, one disease to keep an eye out for is ergot. Ergot is a common disease in North Dakota with a very large host range including small grain crops and grassy roadside weeds.
With the small grain crop approaching maturity, one disease to keep an eye out for is ergot. Ergot is a common disease in North Dakota with a very large host range including small grain crops and grassy roadside weeds. The pathogen prefers cool (70-80 F) and wet weather and infects through the stigma of a wheat flower. Ergot sclerotia can be observed anywhere along a small grain spike, but this year, most of the photos I have received this year have shown ergot on the uppermost spikelet. This could be explained by a possible disruption (ie: heat, sterility) in successful pollination of the stigma allowing the ergot pathogen to infect the grain (Figure 1).
Generally, ergot is observed along field edges due to the close proximity to other grassy weed hosts. However, that is not always the case. In 2018, there were several reports of ergot being reported throughout a few wheat fields in ND. This year, IPM scouts have noticed low levels of ergot in wheat with one field having a higher level of ergot incidence (Figure 2). Therefore, it is important to scout fields prior to harvest, and if needed, implement a harvest strategy to avoid contamination of good quality seed lots. Ergot thresholds are determined as a proportion of sclerotia weight per grain weight with wheat having a threshold of 0.05% and barley at 0.1%. For wheat, this is approximately 10-15 ergot bodies per 2.2 pounds of wheat. For more information on ergot, please read NDSU publication Ergot in Small Grains (PP1904).
Extension Plant Pathology, Cereal Crops
This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.