PERFORMANCE DO FUNGICIDA CERTEZA® N EM TRATAMENTO DE SEMENTES NO CONTROLE DE PODRIDÃO DE RAÍZES EM FEIJOEIRO CAUSADA POR Rhizoctonia solani

Abstract

Among common bean diseases, soil fungi are the main pathogens that cause diseases in common bean crops, especially the fungus Rhizoctonia solani, the causal agent of root rot. The objective of this work was to evaluate the effect of thiophanate-methyl + fluazinam fungicide in the control of root rot in common bean caused by R. solani. Two trials were carried out under greenhouse conditions (in trial A the seeds were inoculated with R. solani and in trial B the substrates inoculated with R. solani), and one in the field (in trial C the seeds were inoculated with R. solani). The treatments were: 1 - non-inoculated control; 2 - inoculated control; 3 - carbendazim + thiram (Derosal® Plus); 4 - thiophanate-methyl + fluazinam (Certeza® N); 5 - metalaxyl-m + fludioxonil (Maxim® XL); 6 - Trichoderma asperellum URM 5911 (Quality® WG). They were emergence, height and cotyledons at 5, 6, 7, 10, 14 and 21 DAS (days after sowing), shoot dry mass, root length and dry mass and severity at 21 DAS and phytotoxicity at 7, 10, 14 and 21 DAS. Inoculation of common bean seeds by R. solani leads to reduced emergence, development and seedling vigor. Seed treatment with methyl thiophanate + fluazinam (Certeza® N) and carbendazim + thiram (Derosal® Plus) reduced the severity of root rot in common bean seedlings at 21 DAS. Seed treatment with thiophanate-methyl + fluazinam (Certeza® N) resulted in better root development and higher productivity, even when compared to the non-inoculated control. The application of Certeza® N was efficient in mitigating the effects, whether in the presence of the pathogen associated with the seed, as well as in protecting the roots throughout their development in the field.