Agronomic Crop Insect Scouting

David Owens, Extension Entomologist, owensd@udel.edu

Soybean
At this point, earworms are largely out of the system. Continue scouting for bean leaf beetle and stink bugs. Large numbers of bean leaf beetle can scar pods, weakening them and potentially allowing disease entry. If pod scarring is less than 8% and there are fewer than 4 beetles per sweep, treatment is not necessary. If there are more than 7, treatment may be advised. Generally, bean leaf beetle counts have been lower than this. Stink bug thresholds rise once plants start moving from R6 to R7 – leaf senescence and seed separation.

Sorghum
Continue scouting the late sorghum for sugarcane aphid. I often do so by walking rows looking for honeydew slicks and areas where bees, wasps, flies, and butterflies are congregating. These insects feed on the honeydew that the aphids excrete, making aphid hotspots easier to find. Thresholds are 30% infested plants with honeydew present up to the soft dough stage.

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