Database Research Summaries2018 Management of Soybean Aphids and Interaction with Soybean Cyst Nematode
Research Focus
The focus of this project is to provide growers with the facts needed to successfully manage soybean aphids, Aphis glycines, and soybean cyst nematode (SCN), Heterodera glycines, in their fields in ND.
Objectives
- Evaluate different insecticide strategies, Rag1 aphid resistant soybean and action thresholds for control of the soybean aphid in ND.
- Determine the yield loss relationship between economic population of soybean aphids on SCN resistant and susceptible varieties grown in ND.
- Survey populations of soybean aphids for development of insecticide resistance in eastern North Dakota.
Results
- The effectiveness of different pest management strategies for soybean aphid was compared including insecticide seed treatments and foliar-applied insecticides. Two application timings were tested for the foliar-applied insecticides: an early R1 (beginning bloom) and the economic threshold (ET = an average of 250 aphids per plant). Results indicated that soybean producers should scout for soybean aphids regularly during the growing season and wait until the ET is reached before making any insecticide application. Also, insecticide seed treatments did not provid an increased yield benefit under low or high aphid pressure over the non-insecticide treated seed with a foliar-applied insecticide at the ET.
- The best pest management strategy for SCN was the use of a SCN resistant variety. The SCN resistant variety significantly decreased SCN population growth, and resulted in a significant higher yield gain, average of 24 bushel per acre, over the SCN susceptible variety. Results suggest that keeping soybeans free of soybean aphids can lead to an increase in SCN.
- Pyrethroid (an insecticide group) failure for control of soybean aphid was reported in 9 counties in 2017. Aphids collected from these problem fields were used to determine if populations were resistant to pyrethroid insecticides. Laboratory bioassays confirmed that about 70% of the soybean aphid populations tested were resistance to pyrethroid insecticides. Insecticide resistant soybean aphids will complicate insecticide management decisions for producers creating a new challenge for soybean production.
Importance
- This information on soybean aphid will improve our understanding of the effectiveness of different insecticide strategies for management of soybean aphids including seed treatments, foliar applied insecticides, application timings and use of Rag1 aphid resistant soybean.
- This research will provide practical information on the interaction between soybean aphids and SCN, increase awareness and help develop viable future recommendations for IPM of these pests.
- An Integrated Pest Management approach will benefit the ND soybean industry by minimizing pesticide costs, soybean pest damage, and risks of pests developing pesticide resistance, thereby increasing soybean productivity and environmental protection.
For more information about this research project, please visit the National Soybean Checkoff Research Database.
Funded in part by the soybean checkoff.
