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Small grains disease and pest report for the week ending June 14

The following article was written by small grains agronomist Dr. Jochum Wiersma and posted to the MN Crop News Blog.

Scouts continue to find tan spot in both winter wheat and spring wheat in their second week of scouting. There were no reports of Septoria spp. or leaf rust. The reported incidence and severity of tan spot increased a bit from the previous week. The risk assessment models mirror their findings as conditions for septoria and leaf rust were not as favorable as have been for tan spot.

As temperatures and relative humidities are forecast to increase in the immediate weather forecast the risk for all three leaf disease complexes are also trending higher.

If you have not completed weed control in spring wheat yet, consider tank-mixing half a labeled rate of a registered fungicide with your weed control program to control early season tan spot in spring wheat when tan spot can found in your fields.

Winter wheat is flowering or Feekes 10.51 in the southern half of Minnesota. To date, the risk model for Fusarium head blight (FHB) continues to be trending low, largely because of the cooler temperatures rather than the absence of precipitation. The immediate forecast continues to indicate a low risk of FHB.

However, the application of a fungicide at Feekes 10.51 to suppress FHB is the final opportunity to control leaf diseases like tan spot, Septoria spp. and leaf rust. Previous research has shown that control of the leaf diseases usually pays in the case of winter wheat. Therefore, I suggest you scout your winter wheat now and consider a fungicide application if any leaf diseases can be found in the lower canopy.

Scouts also found grasshoppers across northwest Minnesota with the highest numbers in Roseau and Kittson Counties.
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