Programs of fungicides to control anthracnose in soybean crop

Abstract

Anthracnose caused by Colletotrichum species is one of the main soybean diseases in Brazil. The objective was to evaluate fungicide programs in the control of anthracnose and productivity in the soybean crop, in an experiment carried out in the 2018/2019 harvest in Lucas do Rio Verde - MT; using cv. Monsoy 8210 IPRO with 20% seed inoculation with Colletotrichum truncatum. The experimental design was randomized blocks with four replications and application of nine fungicide programs at 30, 45 and 60 days after sowing (DAS). Area under the disease progress curve (AUDPC), incidence of symptoms in pods, number of pods/plants, defoliation, mass of a thousand grains, productivity and grain health were evaluated. Pathogen inoculation reduced plant stand and number of plants with cotyledons. The fungicide programs reduced the incidence and severity of anthracnose in the aboveground parts of plants in R5.3 and R5.5. The trifloxystrobin+cyproconazole (30 DAS) and trifloxystrobin+prothioconazole+mancozeb (45 and 60 DAS) programs showed a lower incidence of anthracnose symptoms in pods. The fungicide programs reduced defoliation at the R6 phenological stage. The program pyraclostrobin+epoxiconazole (30 DAS), fluxapyroxad+pyraclostrobin+copper oxychloride (45 DAS) and epoxiconazol+fluxapyroxade+pyraclostrobin+copper oxychloride (60 DAS); program with trifloxystrobin+cyproconazole (30 DAS) and trifloxystrobin+prothioconazole+mancozeb (45 and 60 DAS); and a program with propiconazole+difenoconazole (30 DAS), difeconazole+cyproconazole+chlorothalonil (45 DAS) and azoxystrobin+benzovindiflupyr+difeconazole+cyproconazole (60 DAS), reduced anthracnose AUDPC. Higher yield values and thousand seed weight were obtained with the trifloxystrobin+cyproconazole (30 DAS) and trifloxystrobin+prothioconazole+mancozeb (45 and 60 DAS) programs.