Dr. Kathy S. McLean, Plant Pathologist, 209 Life Sciences Building, Auburn University, Auburn, AL 36849-5409, Phone (334) 844-1956, FAX (334) 844-1947,
Predominant Seedling Disease Complex of Soil Fungi:
Rhizoctonia solani., Pythium spp., Fusarium spp., and Thielaviopsis basicola.
2001 Yield Loss Estimate valued at $390/Bale: 6.5% of the cotton crop was lost to cotton seedling dieases damage ... 44,158 bales ... valued at $10,597,920.
Seven-Year Average Yield Loss Estimate from 1995 through 2001: Annual average of 6.25% of the crop was lost to damage from cotton seedling diseases ... 43,106 bales ... valued at $10,345,440.
2001 Overview and Research Activity: Seedling diseases were again a problem. Rhizoctonia solani, soreshin, was the major seedling disease problem in all parts of the state this past season. Pythium was found in northern regions with the prolonged cool, wet spring. Some growers used the seedling disease point system when putting in their seed treatment and soil applied fungicides this year; but we've had limited success with the point system. Weather conditions after the seed was planted played an important role in determining the fate of our cotton stands. The point system will not improve significantly until we are able to determine more accurately out longer term weather patterns.
Our in-furrow soil applied fungicides were successful in improving cotton stands. Fungicides that had good activity against Rhizoctonia looked particularly good, because Rhizoctonia was the predominant problem. For our next planting season, we will continue to stress the importance of a good seed bed, planting top quality seed, using a fungicide seed treatment, and appling an in-furrow fungicide if needed.
Eight trials were conducted in 2003: Evaluation of Selected In-Furrow Fungicides for Management of Cotton Seedling Disease in the Central and Tennessee Valley Regions of Alabama. Tests were done by Dr. Kathy Lawrence, Department of Plant Pathology, Auburn University.
For details of test results, contact Jennifer Gimpert.