Minnesota soybean growers can improve yield potential with healthier plants

ST. PAUL, MINN. (June 4, 2009) — Insect pressure and unfavorable weather are two culprits that will steal any grower’s soybean yields long before harvest.

Although growers can’t predict what Mother Nature has in store for the 2009 growing season, they can protect their fields from sucking and chewing pests, such as soybean aphids, bean leaf beetles and Japanese beetles.

“Growers should scout their crop weekly to see if there’s an insect problem,” said David Ragsdale, entomology professor and director of graduate studies in entomology at the University of Minnesota. “If the insect population reaches the economic threshold, growers should spray an insecticide to prevent an economic loss. In some of our trials, we’ve seen up to 50 percent yield loss on untreated checks.”

Yield loss isn’t the only problem insects can bring. For example, soybean aphid and bean leaf beetles transmit plant viruses, Ragsdale explained.

Last year, Minnesota grower Daryl Dahlman took the advice of industry leaders and applied an insecticide to his field when he saw significant aphid pressure.

“Last summer, you could see that the beans treated with the insecticide continued to grow, while the untreated plants stunted,” said Dahlman, who farms near Dassel, Minn.

Dahlman said he applied Leverage® 2.7 insecticide from Bayer CropScience to his crop.

“I saw more height and more pods on my beans,” Dahlman said. “And, of course, more pods translated into a 5 bu/A to 10 bu/A advantage over my untreated beans.”

Leverage 2.7 has two modes of action — both contact and in-plant — that provide rapid knockdown and residual protection from a broad spectrum of insects, including soybean aphids, bean leaf beetles, grasshoppers and Japanese beetles. The twofold insecticide offers economic value, as it can be tankmixed with fungicides, herbicides and fertilizers.

“Leverage 2.7 provides growers Stress Shield™ protection from environmental stresses, like extreme moisture or drought, that can reduce plant vigor and yield,” said David Rogers, insecticides product development manager at Bayer CropScience. “The Stress Shield component helps plants remain more vigorous during mildly to moderately adverse growing conditions. This is in addition to the insecticidal benefits delivered by Leverage 2.7.”

University researchers have experimentally determined that the aphid economic threshold is 250 aphids per plant when at least 80 percent of the plants are infested. Treating at the economic threshold prevents aphids from reaching a density where their feeding — and resulting plant damage — will reduce yield. Rogers recommends growers apply 3.8 fl oz/A of Leverage 2.7 at threshold.

Soybean growers can visit AphidAlert to receive the latest information on aphids and other insects. Additionally, they can text the word APHID along with their ZIP code to 46786 to receive free localized alerts when aphids infest their area. Standard text messaging rates apply.

For more information on Leverage 2.7, growers should contact their local Bayer CropScience representative or call 1-866-99-BAYER (1-866-992-2937).