Soybean Aphid
Moderate soybean aphid development risks continue in the forecast across much of the northern soybean-growing region especially west of Lake Michigan as soybeans continue to advance through early reproductive stages of growth. Growers located in or near the Moderate risk area should be regularly scouting any soybean fields that are in the R1-R5 growth stage at this time. Fields from the eastern Dakotas east into Minnesota, northern Iowa, and Wisconsin are at greatest risk of seeing soybean aphid populations build and potentially reach or exceed threshold values for treatment in the next week. While many fields still contain low or even no aphid populations, it is important to continue scouting as favorable temperatures are anticipated for much of this week and soybean aphid populations can quickly increase. Treatment has been needed in some fields in the Moderate risk recently, and field-by-field scouting is recommended as populations will vary even over short distances. Once fields surpass the R5.5 growth stage, yield loss directly attributed to soybean aphid damage is less likely, and focus should be put on fields in earlier growth stages. More isolated soybean aphid problems may be seen in the central Dakotas, northeast Nebraska, central Iowa, far northern Illinois, southern and eastern Wisconsin, lower Michigan, and east into Ontario, Canada.