Soybean Aphid Monitoring

Soybean aphid are difficult to find at this point but I have now found them in 2 fields. The finds are on just a couple of plants in the field, and infested plants have less than 15 aphids per plant. Reports from across the region (Illinois, Indiana and the rest of Ohio) have tended to find aphids but populations are generally not increasing quickly. Our problem locally, if it develops, will likely come from a northern flight of the winged aphid moving into the area rather than a buildup of populations already here. Populations are reaching threshold and some spraying has occurred in Ontario particularly the eastern part, on the other side of Lake Erie. A national reporting system called the IPM-PIPE site is a central reporting location for entomologist. A picture of the 7/17/09 reporting is to the left and you can click here to see the latest updates.

In the meantime, you may want to refresh your knowledge of scouting and management of soybean aphid. First, the threshold is the same as past years, rising populations of aphids that reach 250 aphids per plant when soybeans in R1-R5 stages. This threshold provides a 3-7 day window for application to protect yield. Second, for early season scouting, you will want to focus on the growing point and plus the first fully open trifoliate. Inspect 5 plants, in 20 locations across the field. For more information on soybean aphid along with pictures see OSU Entomology Factsheet 0037.
Another thing you may want to start identifying is bee hives located near your soybean fields. It is the soybean growers responsibility to protect against loss of bees during application.

Below are some specific recommendations for environmental and pesticide factors that will lessen the potential for injury to bees.

1) Drift of pesticide not only can injury non-target plants but bees or other insects located within the canopy of non-target plants. Follow all precautions related to drift such as wind speed, direction identifying risk potential of neighboring crops. Recently we have seen more fields with filter strips or other conservation areas along borders. Plants in these border areas may be in bloom and harboring foraging bees. Drift or spray overlay has the potential to cause injury to bees and should be considered in pesticide applications.

2) Timing of application can limit bee injury. Applications in the evening or early morning are generally best. Bees are less active at these times of the day. Other times when the blooms are less attractive and lower bee activity are acceptable as well.

3) Formulations of pesticides will make an impact on toxicity. Dust and wettable powders are more toxic than emulsifiable concentrates. Ultra low volume applications versus a regular application are generally more toxic. No repellents can be added to tank mixes that will keep bees away from treated areas.

4) Toxicity of pesticides can differ. Most pesticide have been tested with bees in laboratory settings. Keep in mind there can be differences in field results versus laboratory results due to environmental factors as well as the sensitivity difference in populations of bees.

A listing of registered apiaries can be obtained from the Ohio Department of Agriculture. The website is http://www.ohioagriculture.gov/plant/curr/ap/plnt-ap-index.stm. The list can be requested via e-mail to the address apiary@mail.agri.state.oh.us. More information can be found in CORN 2007-26.