FUNGICIDES AND BIOCONTROL AGENTS IN REDUCING CARPOGENIC GERMINATION OF SCLERODIA Sclerotinia sclerotiorum in vitro

Abstract

The experiment in the laboratory was conducted in 2020, where sclerotia of Sclerotinia sclerotiorum were subjected to the application of different chemical and biological fungicides, described as follows: 1-Methyl thiophanate + Fluazinam (37.5+37.5%); 2-Fluazinam (50%); 3-Dimoxystrobin +Boscalid (20+20%); 4-Methyl thiophanate (87.5%); 5-Bixafen + Prothioconazole + Trifloxyxtrobin (12.5+17.5+15.0%); 6-Procymidone (50%); 7-Carbendazim (50%); 8-Trichoderma harzianum 1306 (4,8%); 9-Trichoderma harzianum cepa T-22 (1%); 10-Bacillus subtilus linh. QST 713. Doses indicated by the manufacturers in volume of syrup were used. 100 L. ha -1 . The products were evaluated in two ways: a) by immersing the sclerotia in the properly prepared mixture for a period of five seconds, b) by spraying the mixture onto the sclerotia positioned on the surface of the soil inside acrylic boxes. In the immersion method, the sclerotia were subsequently seeded in water agar medium, ten per Petri dish. In the spraying method, twenty-five sclerotia were distributed inside each acrylic box. In both methods, 200 sclerotia were analyzed per treatment. The sclerotia were incubated for a period of 45 days at a temperature of 16ºC for twelve hours without light and 20ºC for twelve hours with light. After this period, germinated sclerotia were counted. The results indicated that, when the treatments were applied directly to the sclerotia (immersion in syrup), carpogenic germination was reduced, with the treatments Dimoxystrobin + Boscalid and Carbendazim standing out among the best results, while the treatments Procymidone and Trichoderma harzianum 1306 obtained control efficiency similar to the control, while the others presented intermediate performance. However, this effect was not repeated when the products were applied to the sclerotia positioned on the ground. It was also observed under the conditions of this experiment that treatments containing biocontrol agents were not efficient in reducing the carpogenic germination of the fungus and none of the methodologies evaluated.