Tratamento de sementes de soja com fungicida no controle do fungo Cercospora kikuchii

Abstract

The soybean (Glycine max) is one of the most important crops of the Brazilian agribusiness, the grain being widely used in the market, thus allowing the expansion of the cultivated areas by the easy flow of the production. However, the success of all the production can be compromised by the occurrence of diseases among which the Cercospora kikuchii fungus, which affects the seeds of the oleaginous plant, is the cause of the purple spot of the soybean seeds, which is little studied and secondary approach, because it is an end-of-cycle disease. The objective of this work was to evaluate the potential of different fungicides in soybean seeds with or without the presence of the pathogen, on the establishment and components of crop yield. The experiment was conducted between October 2017 and March 2018, in the area located in the municipality of Sete de Setembro - RS, in a completely randomized design (DIC), in a 3 x 3 two-factor scheme (type of seed x fungicide) and 4 repetitions. Seed treatments were TS0 (No treatment), TS1 (Carboxine + Tiram + Fipronil) and TS2 (Fipronil + Piraclostrobin + Thiophanate-methyl) combined with seeds of PIONEER 95R51, spotless, with symptoms of purple spot in the sementen and seeds inoculated with C. kikuchii. Germination, IVE, plant height in stages V9 (vegetative), R2 (full flowering) and R5 (beginning of grain filling), total number of plants in the useful area, number of us and of fertile vegetables, weight of 1000 grains and productivity. The obtained data were submitted to analysis of variance and when significant were submitted to analysis of means of comparison by Tukey 5% probability of error. It was possible to conclude that the use of healthy seeds without the presence of the fungus presents better performance in relation to the others, except in the weight of 1000 grains where it did not differ from those seeds that had fungus symptoms. With regard to the use of chemical treatment, the use of TS1 was on the other treatments. Therefore, the use of healthy seeds without C. kikuchii, and in some cases the use of TS1, guarantee the productivity success for the cultivar used.