Avalia??o de fungicidas no controle de antracnose e mancha alvo, e no rendimento da cultura da soja

摘要

Soybean is one of the main crop in the world, because is a source of food products, for animals and humans, besides its use as biofuels. Although n ew technologies have been used in this crop, its productivity has been limited mainly by the occurrence of diseases, such as anthracnose ( Colletotrichum truncatum) and target spot ( Corynespora cassiicola ) . Thus, the aim of this work was to evaluate the efficiency of fungicides for the control of anthracnose and target spot, applied to the leaves, in a commercial area in the north of Mato Grosso State, Brazil. The experimental design was randomized blocks with eight treatments and three repetitions. The treatments were: T1 - Control; T2 - 1 st Application: Pyraclostrobin + Epoxiconazole, 2 nd Application: fluxapyroxad + Pyraclostrobin; T3 - 1 st Application: Azoxystrobin, 2 nd Application: Azoxystrobin; T4 - 1 st Application: Pyraclostrobin, 2 nd Application: Pyraclostrobin + Epoxiconazol; T5 - 1 st Application: Fluxapyroxad + Pyraclostrobin, 2 nd Application: Fluxapyroxad + Pyraclostrobin; T6 - 1 st Application: Trifloxystrobin + Prothioconazol, 2 nd Application: Trifloxystrobin + Prothioconazol; T7 - 1 st Application: Picoxystrobin + Cyproconazol, 2 nd Application: Picoxystrobin + Cyproconazol; T8 - 1 st Application: Tebuconazol, 2 nd Application: Tebuconazol. The first application of fungicides was at soybean flowering and the second, 15 days after the first application. There was no statistical difference among treatments to plant height, height of 1 st pod, number of pods per plant and number of grains per plant. In relation to anthracnose, treatments did not differ significantly; however, treatment T2 was more efficient in controlling target spot. The treatments that increased the weight of 1000 seeds (g) were T1, T2, T5 and T6, but there was no difference among treatments for productivity (sacks ha -1 ).