Soybean Aphid
Moderate soybean aphid risks continue in the forecast this week especially across the eastern Dakotas, Minnesota, far northern Iowa, and into western Wisconsin. Low risks extend from the central Dakotas and northeast Nebraska as far south as US30 in Iowa and into far northern Illinois as well as southern/eastern Wisconsin, much of lower Michigan, and into southern Ontario, Canada. Growers in or near the risk areas with soybean fields in the reproductive stages of growth but mainly prior to the R5.5-R6 growth stage are encouraged to continue scouting efforts until the field reaches the R6 growth stage. Take note of field populations not just along field edges (where populations are usually highest) but on a field-wide basis before making any decisions on whether or not to treat the field. The majority of fields so far are not reaching threshold, but some treatments have been needed in some areas of the Moderate risk especially in Minnesota and northern Iowa. Once fields reach or surpass the R6 growth stage, yield impact from soybean aphids is negligible and scouting efforts can be discontinued.