Synergistics and Diuron and Paraquat Compatibility on the Development of Sclerotinia sclerotiorum of Baray

Abstract

Fungus Sclerotinia sclerotiorum, which causes the white mould disease, has contaminated several regions with soybean plantations. Correct cultural practice for the control of the phytopathogen is of great interest. The herbicides and studies on their fungitoxic effects are indispensable. Current paper evaluates the effect of two herbicides, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 1,1’-dimethyl-4,4’-bipiridin-dichlorate on the mycelia growth of the fungus S. sclerotiorum. Twenty-five mycelia discs from an isolated scleroid of the fungus were inoculated in BDA plates with herbicides separated or in sets (at concentrations 5, 50 and 500 µg mL-1). Measurements after four days showed that low herbicide concentrations were not affective on fungus development. Similar results occurred in intermediate concentrations. Treatments with 1,1’-dimethyl-4,4’-bipiridin-dichlorate at a concentration of 500 µg mL-1 (R2 = 0.9915) and 3-(3,4-dichlorophenyl)-1,1-dimethyurea+1,1’-dimethyl-4,4’-bipiridin-dichlorateo 500 µg mL-1 (R2 = 1) had an inhibitory effect on the phytopathogen´s mycelia development.