ABSTRACT

Trials were conducted in 2003 at locations in AL, FL, GA, LA, and SC to evaluate thiophanate-methyl (Topsin M 70WP) for suppression of Fusarium hardlock of cotton. Topsin was applied at 0.5 or l lb/A on a 7- or 14-day schedule for a total of 2, 3, or 4 applications beginning at first bloom. No effect on hardlock was found for any of the Topsin treatments. Yields of seed cotton were increased by the application of Topsin, and the number of applications was found to be of more significance than the rate or time between applications. Further research will be required to elucidate the mechanism by which yield of cotton is increased by Topsin M.