Bean Leaf Beetle (also feeds on stems)

Other Information:

Small (1/4"), yellow-buff to reddish beetles, four distinct black spots on their back. Some lack spots, but all color forms have a black triangle at the base of the wing covers. Bean leaf beetles attack soybeans throughout the growing season.  Overwintering adults colonize early-emerging soybean fields, but beetle feeding on cotyledons and unifoliate leaves does not reach economic threshold. One generation in north MN and two in south MN per year. Larvae feed underground on soybean roots and nodules, but this feeding doesn't affect yield.  Adults feed on soybean leaves in July and August. Adults also feed on pods, affecting seed development and allowing disease entry.  These beetles should be treated if damaged pods exceed 10%, or if adults exceed 0.5 per plant, during pod-fill.  Heavy populations should be watched closely and treated aggressively if pod clipping is noted.

Grasshoppers

Other Information:

Grasshopper populations develop during dry springs following long, warm autumns.  With moderate or high moisture, fungal diseases keep grasshopper populations in check. Grasshoppers prefer laying eggs in untilled soil (i.e. roadsides and ditches). Damage first occurs at the margin of fields.  An exception is in fields planted last year with soybean or alfalfa. Grasshopper nymphs look very much like adults, but lack fully developed wings. Grasshoppers feed on leaves and, as soybeans mature, on developing pods.