Get serious about soybean insect management

Soybean management has advanced rapidly over the past decade. Growers are planting earlier, dialing in fertility, using robust herbicide and fungicide strategies and paying closer attention to nematodes—all to pursue higher yields. Yet one area often still lags: insect management.

Insects are frequently viewed as an occasional problem, something to address only when damage is obvious. However, as soybean yields continue to increase, insect feeding during reproductive stages has become a more costly threat. Yield losses can occur long before there are visible symptoms. In today’s high-yield systems, insect management deserves a proactive, targeted approach.

A common mistake is using a one-size-fits-all solution. That approach is unthinkable in weed control but happens routinely with insects. For years, pyrethroid-
based insecticides have been the default tool for soybean pest control. While still important, relying solely on them, especially late in the season, can lead to variable control, shorter residual activity, and even pest flare-ups or resistance issues. 

As with herbicides, insect management demands selecting the proper mode of action for each threat, considering the pest’s feeding habits, movement and interaction with soybeans. The R3 to R6 growth stages are a critical window for protecting yield. During this period, insects that feed on pods, seeds or plant fluids can directly reduce bushels.

Stink bugs are among the most common and economically damaging late-season soybean insects in Missouri. Their piercing-sucking-feeding style damages developing pods by killing or shrinking the seed inside. Because external damage can be minimal, yield loss is often unnoticed until harvest. Pyrethroids, which rely on direct contact with the insect, can provide effective control, particularly when applied with good coverage. However, stink bugs are highly mobile, and their anatomy limits surface contact, which can reduce control consistency, especially as canopies thicken.

Products with neonicotinoids, such as Leverage or Endigo, offer a strong alternative. Neonicotinoid products are systemic, moving in the plant and providing improved control of piercing insects like stink bugs. Once absorbed, neonicotinoids also offer residuals that are not easily washed off by rain, making them a valuable tool during pod fill.

Podworms—also known as corn earworms—are sporadic in much of Missouri, often showing up more consistently in southern areas of the state. When infestations occur, damage can be severe. Soybeans that mature later than adjacent corn are particularly vulnerable, as moths readily move into bean fields during reproductive stages.

Pyrethroids can provide control of caterpillars, but residual activity is often limited. Diamide insecticides, with active ingredients such as chlorantraniliprole, deliver significantly longer residual control and more consistent performance. Besiege, Prevathon and Elevest are examples of diamide chemistry and have proven effective for late-season caterpillar management. These products also diversify modes of action, an important resistance management benefit. While resistance in corn earworm has not been widespread, other caterpillar species, including some armyworms, are already showing increased resistance to pyrethroids in certain areas.

Spider mites often move into soybeans from grassy field edges when conditions are hot and dry. Normally, beneficial insects help keep mites under control, but extended heat and drought can allow populations to explode. Compounding the problem, many pyrethroids reduce beneficial insect populations and can intensify a mite outbreak. One exception is bifenthrin, found in products such as Hero and Elevest. Bifenthrin is a proven, effective solution when spider mites reach economic thresholds. Knowing the difference is critical when selecting insecticides in drought stress.

Successful insect management requires scouting, awareness of economic thresholds and intentional insecticide selection based on the target pest—not convenience or habit. Talk with your MFA agronomist to choose the right chemistry at the right time to protect soybean yield and profitability. 

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