It is always important to scout for potential problems. In a general sense insects become more prevalent during dry seasons. Insects can damage quality and reduce yield.

In soybeans, the most critical insect to watch for is the SOYBEAN APHID which originates from Asia and has generated a lot of management questions. The soybean aphid is a small, yellow insect with distinctive black cornicles on its back.

Most are found on the young leaves, including the underside. The aphid sucks nutrients from the plant, producing a sweet, sticky substance on the surface. Aphid feeding can also spread damaging viruses. Research has shown that when threshold levels are over 250 aphids/plant on an average of 30 plants/field, spraying becomes economical. The most critical stage of growth for soybeans is from flowering (R1) to pod fill (R6).

POTATO LEAFHOPPER pressures in dry beans start to be an issue 4-6 weeks after planting as Cruiser’s efficacy runs out. In particular fields that border alfalfa hay fields generally are at higher risk. Growers should scout fields and look for both nymphs on the underside of leaves as well as adult leaf hoppers. The threshold is 0.5/trifoliate up until 4th trifoliate where it increases to 1/trifoliate. The threshold increases to 2/trifoliate at bloom. 

Later in the season our attention turns to TARNISHED PLANT BUG . Damage from this insect comes during the flowering to pod fill period. The tarnised plant bugs are oval, 1/2 inch long, usually light to dark brown with a distinctive V-shaped marking on the centre of their back.

During flowering and early pod fill, the plants are soft and easily pierced by the tarnished beetle. Punctured beans are left with a mark which results in these beans becoming pick. If you find one or more tarnished plant bugs per plant at flowering, the threshold has been reached. •