Bean Leaf Beetle in Early Emerged Soybeans
Early (late-April to early-May) planted soybeans are now seeing feeding from bean leaf beetles. The bean leaf beetle can be one of the most damaging soybean pests in the United States. It is tied for second among all pest species attacking soybean foliage, pods and seeds.
The bean leaf beetle overwinters in adjacent areas to fields. Adults become active in the spring and seek available host plants, such as soybeans. Adult coloration varies widely from red, orange and tan; and markings can vary widely too with beetles having dots, strips, both, or neither. However, all adults possess a black triangle at the base of their forewings. A female beetle is capable of producing up to 200 eggs. The reddish, spindle-shaped eggs are laid adjacent to plant stems in the upper 5 inches of the soil.
Image courtesy OSU Extension CORN Newsletter corn.osu.edu
Remember that it takes significant defoliation, well over 50%, before economic concerns, which is seldom seen. However, because of the scarcity of emerged soybean fields, fields that are already emerged, should be scouted for the possible presence of larger than normal numbers of bean leaf beetle. Without a lot of other soybean fields for the beetles to spread their numbers over, the few fields that are emerged might be getting more adult beetles than usual.
Typical Bean Leaf Beetle damage to soybeans. (photo credit A. Kleinschmidt)
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