Avaliação da eficiência de fungicidas no controle de mofo branco (Sclerotinia sclerotiorum) na cultura da soja

Abstract

Soybean production was 133,692.3 million tons in 38.2 million hectares in the 2020/21 harvest, representing an increase of 7.1% compared to the previous harvest. Among the main factors that limit of high yields in soybeans are diseases. Approximately 40 diseases caused by fungi, bacteria, nematodes and viruses have been identified in Brazil. This work aimed to evaluate the efficiency and agronomic feasibility of fungicides in the control of white mold (Sclerotinia sclerotiorum) in soybean crop. The work was conducted in the field from 12/24/2020 to 03/18/2021, at Fazenda Chumbo, located on BR 262 km 645 in the municipality of Ibiá – MG. The sowing of Brasmax Voraz IPRO variety occurred on the day 11/11/2020. The statistical design adopted was in randomized blocks, with 7 treatments and 4 replications. Each plot consisted of 6 lines of 6 meters in length and 0.5 spacing between lines, making a plot with an area of 3 x 6 = 18 m². The treatments tested are described in table 2. Two applications were carried out via foliar with pressurized back spray (CO2). Were evaluated of disease severity, phytotoxicity and productivity. It was concluded that: the fungicide Spot (dimoxystrobin + boscalide) was the most efficient in controlling white mold, in reducing the incidence, severity, disease index of the pathogen and in replacing sclerotia (60 % reduction); The use of Spot and Aprove (fluazinan + thiophanate methyl) showed higher yields above 1000 kg compared to the control; The association of FoxXpro + Serenade (Bacillus subtilis) / FoxXpro (prothioconazol + trifloxystrobin + bixafen) allowed a productive response in 586 kg more than the control and with a control of 72% for the disease index and reduced by 40% the replacement of sclerotia in the ground; The best controls for white mold progress in the experimental area, with a population above 7 sclerotia per square meter were Spot (90%), followed by Fluazinan (85%), Sumilex (procimidone) (80%) and Aprove (74%)