1. USDA-Agricultural Research Service, Richard B. Russell Agricultural Research Center, P.O. Box 5677, Athens, GA 30604-5677. Mention of trademark or proprietary products does not constitute a guarantee or warranty by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that may also be suitable.
2. Corresponding author. E-mail: wbarton@athens.net
3. USDA-Agricultural Research Service, Southern Regional Research Center P. O. Box 19887, New Orleans, LA 70179.