Integrated Crop Management News

Bean leaf beetle adults (Photo 1) are susceptible to cold weather and most will die when air temperatures fall below 14°F (-10°C). However, they have adapted to winter by protecting themselves under plant debris and loose soil. Each spring, adult beetles emerge from overwintering habitat and migrate to available hosts, such as alfalfa, tick trefoil, and various clovers. As the season progresses, bean leaf beetles move to preferred hosts, like soybean. While initial adult activity can begin before soybean emergence, peak abundance often coincides with early-vegetative soybean.

As of May 6 2019, 36 percent of Iowa’s corn is planted according to the USDA-NASS. Under cool conditions (50 to 55^oF soils), it may take more than three weeks for corn to emerge whereas corn in 70^oF soils can emerge in less than a week (Licht et al., 2001).

Iowa’s most significant soybean insect pest, soybean aphid, has host-alternating biology. This species has multiple, overlapping generations on soybean in the summer and moves to buckthorn in the winter. Fall migration to buckthorn is based on senescing soybean, and decreasing temperatures and photoperiod. For the majority of the year, soybean aphids are cold-hardy eggs near buckthorn buds (Photo 1). As spring temperatures warm up, soybean aphid eggs hatch and produce a few generations on buckthorn before moving to soybean (Photo 2). Tilmon et al.

Flood waters are receding, but the challenges in recovery for farmers and livestock producers are just beginning. We recommend producers get out in their fields as soon as possible to assess the damage to pastures and hay ground, then check out possible disaster assistance. Look for three things in the assessment: debris, silt on the forage, and thinned or dead forage plants. Debris includes wire, metal and trash that may be injurious to animal health and is usually found along fence lines and in the corners of fields.