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Increasing Soybean Aphid Populations Forecast
Researchers at North Dakota State University advise there’s a slightly higher risk of increased soybean aphid populations this growing season. Researchers at the University of Minnesota support that advisory and are reporting low overwintering mortality rates for soybean aphids due to the mild 2024 winter.
Arrival and Population Trends
Farmers experienced increased numbers of soybean aphids across the upper Midwest around the turn of the century. Populations migrated into Iowa and Minnesota in 2003; and by 2008, soybean aphid levels were horrendous. Insect movement and infestations are highly cyclical, which is why frequent scouting is so important. Scouting reports verified that, over the next decade, aphid population numbers dropped and farmers almost stopped worrying about soybean aphids.
Then came the summer of 2024, and scouts started recording higher counts. When farmers made applications with many of the historically widely-used insecticides, control was limited in some cases, especially from pyrethroids.
Soybean aphids reproduce quickly, sometimes doubling population numbers in five to seven days, and can migrate more than 100 miles — often moving into neighboring states in high numbers.
“Farmers in the eastern areas of North Dakota, especially in the Red River Valley, and southern parts of Minnesota should scout often and be prepared to pull the trigger on applications,” says Ron Geis, market development specialist, Corteva Agriscience. “From what I’ve seen in my area and from conversations with farmers who have used neonicotinoid seed treatments, they only hold down populations for a while and only when those populations are low.”
Farmers may apply herbicides and fungicides before weeds or diseases even appear but do not have to invest in an insect control application until they see soybean aphid numbers reach economic threshold.
Control Options
Geis advises farmers to have more than one mode of action in their insecticide program toolbox in preparation for increased aphid populations.
“Scout often and have a baseline number of aphids per plant you use to guide the decision to spray,” Geis says. “Whether that number is 50 per plant or the more broadly accepted 250 aphids per plant, at least you will have solid information on which to rely.”
Farmers are hearing more about and starting to lean on a product that delivers excellent control of soybean aphids: Ridgeback® insecticide with Isoclast® active.
“Ridgeback insecticide provides farmers with a novel ingredient, Isoclast active, with the trusted power of bifenthrin for broad-spectrum soybean pest control,” Geis says. “That dual mode of action will allow farmers to target and have the potential to control many soybean pests, including soybean aphids, loopers, Japanese beetles, spider mites and other worms, through contact and ingestion.”
Geis advises using a rate of 10.3 fluid ounces per acre if pyrethroid-resistant soybean aphids are present.
“Stay ahead of infestations,” Geis says. “Even if you used seed treatments, keep your head over your crop and reach out to your ag retailer for Ridgeback insecticide with Isoclast active.”
For more information on the insecticide portfolio from Corteva Agriscience, visit Corteva.us or your local Corteva Agriscience representative.
Ridgeback ® is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Isoclast® is a registered active ingredient. Always read and follow label directions.
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