Plenty of people from the University of Illinois and the Illinois Natural History Survey have been searching for soybean aphids that overwintered on buckthorn, Rhamnus species. Until recently, no one had found the little critters. However, David Onstad, associate professor in the Department of Natural Resources and Environmental Sciences, found two soybean aphids on a Rhamnus shrub in Kane County on May 7, 2001. His discovery answers one of the burning questions about this pest: Will soybean aphids survive the winter in Illinois?|
Now the watch begins. David's finding only two aphids doesn't mean that soybean aphids will become problematic in soybeans again this year. However, knowing that they're still present in the state at least gives us a "heads up."
In issue no. 1 (March 16, 2001) of the Bulletin, I mentioned that we would establish a network of suction traps to determine when soybean aphids begin flying from buckthorn to soybean. On May 8, one trap was erected at the University of Illinois Crop Sciences Research and Education Center (South Farm). The trap is approximately 25 feet tall and will sample flying aphids within a 30-mile radius. (Not all of them, mind you. What an incredible control tool that would be.) During the next couple of weeks, a crew of people from UrbanaChampaign will be erecting suction traps at six additional locations: Freeport (Stephenson County), DeKalb (DeKalb County), Monmouth (Warren County), Perry (Pike County), Brownstown (Fayette County), and Dixon Springs (Pope County). The suction traps in the northern locations will be erected first.
The cooperator at each site will retrieve the collection bottle at the base of the trap once each week and send it to David Voegtlin, aphid specialist at the Illinois Natural History Survey. He and his coworkers will sort through the samples looking for soybean aphids. We will begin reporting captures of flying soybean aphids as soon as we receive them in the collections. The data will be reported on a page (currently under construction) at the IPM Web site; this data-reporting page will be available within a couple of weeks. Also, as the season progresses, we will pick up reports about soybean aphids throughout the Midwest and keep you informed.
Again, we have no idea whether soybean aphids will be prevalent or scarce in Illinois and elsewhere this summer. However, a lot of people are watching the situation very carefully, so you will know what we learn as quickly as we can get the information out.--Kevin Steffey