Progresso e controle da mela-das-sementes (Claviceps maximensis) de Brachiaria brizantha

the efficiency of one or two applications of pyraclostrobin + epoxyconazole, mancozeb, triadimenol, azoxystrobin + cyproconazole, trifloxystrobin + cyproconazole or tebuconazole in the control of honeydew in seeds of brachiaria brizantha cvs. marandu and xaraes was verified during crop 2004-05. the inductors of resistance acibenzolar-s-methyl and potassium silicate (applied in aerial part or in soil) were evaluated. triadimenol, with one or two applications, pyraclostrobin + epoxyconazole, azoxystrobin + cyproconazole, trifloxystrobin + cyproconazole or tebuconazole, with two applications, were the fungicides most promising in the control of disease in marandu grass. about cv. xaraes, better control was reached with pyraclostrobin + epoxyconazole, independent of number of applications, triadimenol, trifloxystrobin + cyproconazole or tebuconazole, with two applications. correlation between production of pure seeds and of disease intensity was not detected. with regard to the progress of honeydew in seeds of b. brizantha cvs. marandu and xaraes, observed the disease occurred in cold periods with high humidity. in cv. marandu the pathogen occurred in final phase of culture, while in cv. xaraes the honeydew was detected in phase of intense bloom. constant increases of disease intensity were observed in two genotypes. the honeydew occurred in 64% of panicles of cv. marandu and in 81% of panicles of cv. xaraes; about 20% and 18% of flowers/seeds, respectively, was affected. the results verified high positive correlation between the values of incidence and severity of disease.