Soybean Aphid
Moderate soybean aphid risks remain across northern Iowa into southern and central Minnesota this week with additional Moderate risks now in place across northwest Minnesota and far eastern North Dakota. Low risks are predicted across eastern South Dakota, central North Dakota, northeast Nebraska, the remainder of Minnesota, northern and central Iowa, northern Illinois, Wisconsin, lower Michigan, northern Indiana, northern Ohio, and southern Ontario, Canada. Scattered reports of economic thresholds being met or exceeded as well as some insecticide treatments continue to come in especially from within the Moderate risk area, however, many fields especially across the southern portion of the risk region are now advancing past critical growth stages where yield loss from soybean aphids occurs. Nonetheless, late planted or re-planted fields still in growth stages prior to R5 should continue to be scouted regularly. In addition to crop growth stage, treatment decisions should be made based on what populations are doing in specific fields and not necessarily what neighbors are doing or what the regional report is suggesting. Soybean aphids are hit and miss especially in areas that contain fields with varying planting dates. Weather conditions across the risk area especially west of Lake Michigan may be less favorable for continued soybean aphid population increases in the week ahead as prospects for locally heavy rainfall and potentially warmer temperatures may result in slower or less widespread population increases.