Small Grains Disease and Pest Update 06/30/25

 Diseases

Last week, the scouts continued to find a few fields with tanspot at low incidence and severity. Weather fronts continue to bring scattered showers across much of Minnesota.  Only the northern halves of Kittson and Roseau counties continue to miss these showers and thunderstorms, and wheat fields in that area are showing signs of moisture stress. Consequently, the conditions for developing small grain diseases, including FHB, are much more favorable for most. However,  as a consequence of the hit-and-miss nature of these rain events, both the NDAWN disease forecasting and the national risk model might be overestimating the risk for some of your fields if last week's rains kept missing your fields and fields are much drier (and therefor less likely to accumalate the needed leaf wetness duration periods) than estimated by the tools when the tools extrapolate the data from the data collection points to your fields in the coming days. 

For oats and barley that will be reaching Feekes 10.5 (or fully headed), use to a fungicide labeled for the suppression of FHB, as the risk forecast for the remainder of the week remains moderate to high across all but the most northern counties in NW and the most southern counties in the SW corners of the state. Likewise, apply a fungicide labeled for the suppression of FHB in wheat when the crop reaches Feekes 10.51 (or beginning of anthesis). Choose one of the premium fungicide products when your variety has a FHB rating of susceptible to very susceptible (>6 or higher) 

Insects  

Aphids continue to be found across Minnesota. Fields in the heart valley are most likely to be at the economic threshold. Likewise, the scouts also continue to find the cereal leaf beetle (CLB) in the same area. The economic threshold for CLB is one larva per flag leaf once the crop reaches the boot stage.