WOOSTER, Ohio -- Soybean growers have an added decision-making tool in scouting for the soybean aphid.
U.S. Department of Agriculture's Pest Information Platform for Extension and Education (http://sbrusa.net), created last year to track the development of soybean rust throughout the United States, has added information to track and manage the soybean aphid. The site relies on reports from across the country on insect and disease development in sentinel plots.
However, the interpretation of the data on this Web site is not used in the same manner as with soybean rust, said Ron Hammond, an Ohio State University research entomologist with the Ohio Agricultural Research and Development Center.
"Growers will not use the aphid information like they use the soybean rust information," said Hammond, who also holds an OSU Extension appointment. "That's the critical difference between this program for rust and the program for aphids that we have to make clear to growers. Rust may cover a lot of fields in an area, so if one field has it, others might be at risk for it so you may have to treat your field to prevent it. That isn't the situation with insects. Finding the aphid in your area has nothing to do with your own fields. You cannot make any decisions based on what happens in any other field in your area. You have to sample each field individually."
Hammond and other entomologists are encouraging growers to maintain an Integrated Pest Management (IPM) strategy when managing the soybean aphid, as with other field pests.
IPM is a strategy that involves constant field scouting and monitoring of pest development and recommends action taken only when insects reach damaging thresholds. IPM practices involve situations with individual crop fields. By contrast, the spread of diseases, like soybean rust, can impact several fields in an area, thereby requiring fungicide applications as a preventive or control measure.
The prediction that soybean aphid populations are expected to be low in Ohio this season further complicates the situation.
"The information on this Web site, as a research tool, can provide us with a lot of historical data to see where we've had problems and where thresholds have been reached," said Hammond. "We don't want to see the information provided used in the wrong way. And if companies tell you that you should be spraying because aphids in nearby sentinel plots have hit threshold, then they are just trying to sell you a product."
Additionally, Ohio State researchers discount using insecticides in soybean fields when not warranted just to boost plant health.
"OARDC research has shown that spraying insecticides or fungicides in fields when not needed does not give an economic return," said Hammond. "Spraying when the aphid reaches the threshold of 250 insects per plant is where you get the best return, not as a preventive measure and not for plant health."
Ohio growers are encouraged to consult Ohio State's Agronomic Crops Team Crop Observation and Recommendation Network (C.O.R.N.) newsletter for weekly news and recommendations on crop-related issues. The newsletter can be found at http://agcrops.osu.edu.