BACKGROUND: Soybean cyst nematode, Heterodera glycines, and soybean aphid, Aphis glycines, are invasive, widespread and economically important pests of soybean, Glycines max, in North America. Management of these pests relies primarily on use of pesticides and soybean germplasm with genetic resistance. A three-year field study and complementary greenhouse experiment were conducted to determine the benefits of host-plant resistance (HPR) and pesticidal seed treatments for managing pest populations and preserving soybean yield.

RESULTS: Host-plant resistance significantly decreased the abundance of A. glycines and, in most study sites, suppressed H. glycines. Neonicotinoid seed treatment reduced A. glycines abundance on the cultivar that was susceptible to both aphids and nematodes, but abamectin nematicide seed treatment had no effect on H. glycines populations in the field or greenhouse.

CONCLUSION: These results suggest that the seed treatments included in our experiments may suppress pests, but not consistently for all soybean cultivars or study sites. Ultimately, HPR more consistently reduced pest numbers compared to the use of pesticidal seed treatments. The planting of HPR cultivars should be a primary tool for integrated pest management of both soybean pests.