With the improvement of soybean genetics and commodity prices, odds are farmers are producing more soybeans — and on better ground — than they did 10 years ago. This increased profit potential brings with it a new agronomic challenge related to crop rotation.
Crop rotation less effective at pest management
Traditional crop rotation practices typically benefit fields by mixing up soil composition and helping balance soil nutrients from year-to-year. In most cases, this crop rotation also helps vary the insect profile from year to year.
Of course, the stink bug found a way to make itself an exception. One of the most damaging insect pests to cotton, the stink bug can be as damaging to soybeans. This means the practice of crop rotation is less effective at managing stink bugs as it is with other pests and other crop rotations.
Cotton bollworm and corn earworm are two more pests that are not controlled with a cotton-soybean rotation, as the two worms are, in fact, the same pest — Helicoverpa zea.
70% of insect-related soybean losses
Land grant universities in Mississippi, Louisiana, Virginia, Arkansas, Alabama, North Carolina and Tennessee develop an annual report about the effect of insects in soybeans. The 2013 report found stink bugs are the most damaging insect in Alabama, Louisiana, Mississippi, Tennessee and Virginia. Across all states in the study, stink bugs are responsible for an increasing proportion of soybean yield insect losses. Perhaps most important, stink bugs and corn earworm combined with soybean looper to account for more than 70 percent of all insect-related soybean costs and losses in these states in 2013.
Managing soybean pests
So what’s the best way to manage these pests in soybeans? Many agronomists and researchers recommend a two-application approach in soybeans.
One methods of controls is an early season application of a a labeled insecticide to control control worms, including corn earworm and soybean loopers. A second pass during the soybean reproductive stage can control stinkbugs. is a common choice for this second pass. In addition to insect control, the choice of tankmixing with a fungicide to provide disease and insect control in one pass needs to be an option.