Organic Control of Aphids in Soybeans
Soybean aphid has been difficult to control with OMRI approved insecticides during outbreaks. Through use of an air-assist sprayer, the project would evaluate if improve plant coverage might improve performance of insecticides and prove beneficial for other, foliar applied, agricultural compounds in organic systems.
- Mark Askegaard
- Lynn Brakke
- Dan Oldsgaard
- Phil Wilder
- Phil Glogoza, Extension Educator
- Sustainable Agriculture Research and Education - SARE
- MN Soybean Research and Promotion Council
Goals: Spray delivery and coverage may be factors in effectively using some OMRI approved insecticides to manage soybean aphid during infestation outbreaks. The study was designed to look at improved spray coverage and the effect on control levels of OMRI insecticides.
The sprayer was evaluated to assess the spray deposition pattern to provide effective coverage throughout the soybean plant canopy at a practical spray volume, tractor speed, swath width, and volute angle. Using water sensitive paper, it was determined that a volume of 10+ GPA, tractor speed of 5 MPH, swath of 25 feet, and a volute angle of 7 degrees below parallel to the ground was suitable for initial testing.
The primary OMRI approved insecticide that was evaluated was natural pyrethrum (Pyganic®). It was applied in water at rates of 16 and 24 fl oz of product per acre. Though the insecticide did not reduce the aphid infestation to the same levels as a synthetic insecticide customarily does, the pyrethrum did reduce populations to a level that appears to have been tolerable to the plants. Initial population reductions averaged about 40% and reached an upper average of about 60% .
In addition, neem (Dagger®) and some other plant essential oil formulations were quickly assessed for potential efficacy . No effects were immediately observed.
Similar results were obtained in 2010. Sprayer coverage was adequate but the best performance by Pyganic was a 50 - 60% reduction in infestation levels.
- SARE: $18,000
- MN Soybean and Promotion Council: $11,000
NW Regional Sustainable Development Partnership - $5350Last updated 11-3-2008