The conditions for disease development have further declined across the state with initial infections of the leaf spotting diseases, leaf rust, and Fusarium head blight being unlikely. I expect that the increase in dew points that are forecasted across much of the state will increase the risk of disease development only slightly and only in areas or fields that received substantive precipitation in the past week and a half or that are under irrigation.

The decision to apply a fungicide to suppress FHB in winter wheat or the earliest seeded barley and spring wheat or control crown rust in oats is a difficult one at this junction in time as the extreme heat over the weekend and the predicted daytime highs in the extended forecast do not favor grain fill and thus yield potential.

The sudden change from cold to hot weather and the application of herbicides are resulting in some weird crop responses that in some cases mimic leaf spotting diseases. Make sure that you identify the cause of these leaf spots before applying a fungicide.

Up to this point, the dew points have been low enough that nighttime temperatures stayed in the 50 and 60 across much of the state even as daytime highs soared to triple digits. This has meant that respiration during the night has stayed relatively low and not taken more photosynthate away from the developing kernels.

Meanwhile, reports of aphids and grasshoppers continue to reach me with a larger proportion of reports having numbers that warrant treatment. Scout field edges for grasshoppers and scout the whole field in the case of aphids to determine whether you are reaching economic thresholds and decide to apply an insecticide.

--Jochum Wiersma, Small Grains Specialist, University of Minnesota