Effect of spray droplet size, spray volume and fungicide on the control of white mold in soybeans

Two experiments were conducted at different locations, the first in the 2012-13 season, and the second in the 2013-14 season, to evaluate the effectiveness of fluazinam and procymidone fungicides applied at volumes of 100 and 200 L ha−1, using three types of nozzles (hollow cone, flat fan, and air induction flat fan) in soybean, for the control of white mold (Sclerotinia sclerotiorum Lib. de Bary). This study assessed white mold incidence, severity, sclerotia production and yield. In the 2012-13 crop season experiment, there was no difference between the spray volumes of 100 and 200 L ha−1 for any of the white mold assessments. With regard to the nozzles, the use of the air induction flat fan nozzle resulted in lower incidence and production of sclerotia. In the 2013-14 season experiment, the use of the flat fan nozzles, and the air induction flat fan nozzles resulted in the lowest rates of white mold incidence. Procymidone promoted a reduction in sclerotia production in comparison with fluazinam. No differences in yield were detected between the studied factors. Therefore, it was concluded that the spray volume did not influence the control of white mold and the use of air induction nozzle was efficient in controlling white mold in soybeans.