Effect of fungicides on survival of Bradyrhizobium japonicum (Semia 5019 and Semia 5079) and soybeans nodulation - DOI: 10.4025/actasciagron.v25i1.2676

Abstract

The effect of fungicides on survival of Bradyrhizobium japonicum Semia 5019 and Semia 5079 and nodulation on soybean plants was evaluated in Brazil. The capacity of multiplication of bacteria in YMA liquid mean with two concentrations of benomyl, carbendazim, carboxin+thiram, difenoconazole, thiabendazole+thiram, thiophanate-methyl, carbendazim+thiram fungicides was compared in vitro. Survival of bacteria was measured by transferring of serial dilution in YMA mean. In greenhouse, seeds (cv. “Embrapa 48’) were treated with thiabendazole+thiram, metalaxyl, thiram, difenoconazole+thiram, carbendazim+thiram, fludioxonil+metalaxyl-m, thiophanate-methyl+tolyfluanid, thiabendazole and captan fungicides. Inoculant containing both bacteria strains was inoculated in a proportion of 10 g/Kg of seeds. Nodulation in soybean plants was measured counting the total number of nodules and those on the main root. Reduction over 10% was observed in relation to control in multiplication of B. japonicum in means containing thiram, carbendazim, carboxin+thiram and carbendazim+thiram. Tested fungicides did not affect nodulation. Only captan fungicide reduced the number of nodules in the main root when compared to control (not inoculated).