Effectiveness of Chemical Seed Treatments in Controlling Karnal Bunt Disease of Wheat. E. J. Warham, Seed Health, Wheat Program, CIMMYT, Apdo. Postal 6-641, Mexico 06600 D.F., Mexico. J. M. Prescott, and E. Griffiths. Seed Health, Wheat Program, CIMMYT, Apdo. Postal 6-641, Mexico 06600 D.F., Mexico, and Department of Agricultural Botany, University College of Wales, Penglais, Aberystwyth, Dyfed, SY23 3DD, Wales, U.K. Plant Dis. 73:585-588. Accepted for publication 28 January 1989. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0585.

Forty-seven chemical products recommended for the control of bunts and smuts were screened for their effectiveness as wheat seed treatments to control Tilletia indica. Chemicals that reduced teliospore germination appeared to be limited in the length of their activity. Most were effective for up to 6 mo, but only a few for longer periods of time. Of those with a longer period of activity, triphenyltin hydroxide, methoxyethylmercury acetate, and ethylmercury chloride were effective for up to 18 mo. However, with the possible exception of the mercurial compounds, none was capable of killing T. indica teliospores when applied to infected seeds. There is currently no chemical seed treatment that can guarantee that wheat seed is not carrying viable T. indica teliospores.