Joint use of fungicides, insecticides and inoculants in the treatment of soybean seeds

Resumo

The interference of the joint application of pesticides with seed inoculation on the survival of Bradyrhizobium has
been reported in the last years. So, the objective of this study was to evaluate the joint use of fungicides, insecticides and
inoculant in the treatment of soybean seeds on various parameters of Bradyrhizobium nodulation in soybean as well as
on crop productivity parameters. The experiment was conducted during the 2013/2014 crop in the experimental field of the
Instituto Federal de Educação, Ciência e Tecnologia de Mato Grosso – Campo Novo do Parecis Campus. The seeds of
TMG 133 RR variety were sown in pots. It was used a randomized block design in a 4 x 4 + 1 factorial, four fungicides (1:
fludioxonil + metalaxyl-M, 2: carboxine + thiram, 3: difeconazole and 4: carbendazim + thiram), four insecticides (1: fipronil
250 SC, 2: thiamethoxam, 3: imidacloprid + thiodicarpe and 4: imodacloprid 600 FC) and an inoculant (SEMIA 5079 and
SEMIA 5080), common to all treatments, with three replications. The experiment was not repeated. The joint application of
fungicide and insecticide with inoculant does not affect nodulation, foliar N content and vegetative growth of the plants
as well as the masses of grains per plant and 100-grain mass. The use of the carbendazim + thiram mixed with fipronil and
carbendazim + thiram mixed with imidacloprid provides less number of pods per plant and grains per plant, reflecting in
reductions in the production of soybean grains. In this way, the fungicide carbendazim + thiram, regardless of the
combined applied insecticide, is the most harmful to Bradyrhizobium spp.