NUMBER OF TEBUCONAZOLE APPLICATIONS FOR MAXIMIZING DISEASE-CONTROL AND YIELD OF PEANUT IN GROWERS FIELDS IN ALABAMA

Disease and yields of peanut were monitored in growers' fields treated with zero, one, two, three, and four applications of tebuconazole. Yi elds ranged from 1,918 to 6,891 kg/ha and averaged 4,319 kg/ha over ei ght locations in 3 study years. Defoliation caused by peanut leaf spot s (Cercospora arachidicola and Cercosporidium acutatum) and incidence of southern stem rot (Sclerotium rolfsii) were inversely related to nu mber of tebuconazole applications, while yield was directly related to number of tebuconazole applications. Average yields with zero, one, t wo, and four tebuconazole applications (each application at 0.25 kg a. i./ha) were 3,609, 4,088, 4,526, and 4,868 kg/ha, respectively. Data f rom each location were best modeled by quadratic equations allowing de termination of numbers of tebuconazole applications for minimal diseas e and maximal yields. Calculated spray numbers indicate that between t hree and four applications of tebuconazole is best for disease control and yield maximization.