The wheat crop in 2011 rebounded nicely from the low acreage and mediocre yields of 2010, with tripling of seeded acreage to 760,000, and an average yield of 61 bushels per acre, up from 56 in 2010. Quality was very good in 2011.
The University of Illinois variety testing program conducts wheat variety trials at six locations in Illinois each year, with entries made on a fee-paid basis by commercial seed companies. Yields were good at all six locations in 2011, with averages over all entries ranging from 71 bushels per acre at Dixon Springs and Perry to 89 at Urbana. Top varieties at each location generally yielded about 15 bushels more than the trial average.
Over the past five years, the use of seed-applied insecticide (STI) in addition to seed-applied fungicide has grown, from small numbers of entries in these trials to more than half of them. Seed companies can submit entries with or without STI, and STI used is noted in the results.
We also include in the trials several varieties with and without STI. Yield responses to STI have typically been higher in southern than in northern Illinois, most likely because STI prevents fall infestations of aphids that carry barley yellow dwarf mosaic virus (BYDMV), and such aphids are more common in southern Illinois.
In 2011, insecticide seed treatment produced a yield advantage at all locations, ranging from 2.5 bushels at Brownstown to 8.7 bushels at Belleville, and averaging more than 6 bushels in both the north and south regions. Such large and consistent responses in northern Illinois are unusual. We don't think that aphid infestation was widespread in the fall of 2010, so we're not sure why this happened. We would generally expect less response on BYDMV-resistant varieties.
Results of these trials are available on the Department of Crop Sciences variety testing web site.