Other Aphid Biological Control Work

NCSRP-Funded Soybean Aphid Project 2006-2009
The new NCSRP- funded project is focused on refining the economic threshold, evaluating aphid resistance in new cultivars, and developing tools that can predict an aphid outbreak in the region and at the field level.

To accomplish these goals a coalition of entomologists and plant breeders located in 9 states are working together to address these specific objectives:

1. Economic threshold - An often-asked question is how many predators does it take to prevent soybean aphids from reaching the economic injury level (EIL)? We know that predators are very important regulators of soybean aphid populations, but as of yet we have not been able to answer this question. What are the key predators? Do they vary from field to field, year to year, state to state? How can we quickly assess their abundance?
2. Resistant varieties - We are also working with soybean breeders to evaluate aphid resistant varieties being developed. We currently have soybean lines from 3 University programs and from a number of private companies under evaluation in 6 states. As breeders continue to expand their seed supplies, more lines will be tested at multiple locations each year.
3. Predictive tools - We have developed a simple aphid population growth model, Soybean Aphid Growth Estimator, or SAGE model. The only variable in this current model is temperature. The model predicts the maximum population growth that can be expected based on temperature and forecasts the population growth possible in the next 7 days. A downloadable Microsoft® Excel spreadsheet is available at the University of Minnesota Just for Growers website.

Work is continuing on other predictive tools. The new NCSRP project supports, in part, a regional Suction Trap Network. The fall flight activity based on Illinois data is predictive of aphid populations the following spring. The utility of a regional trapping network in identifying areas of high overwintering (fall) populations might provide crop professionals a warning of where a soybean aphid outbreak might occur.

Submitted by Dr. David Ragsdale, Department of Entomology, University of Minnesota, October 2006