Effect of Fungicide Application Timing on Sclerotinia Sclerotiorum Infection Rate and Yield in Winter Oilseed Rape

Abstract

In experiments on winter oilseed rape during 2013–2016, we examined the influence of timing of fungicides application at BBCH 61–63 and BBCH 65–67 for fungicides containing active ingredients based upon new triazoles, strobilurins and SDH inhibitors (cyproconazole 80 g/l a.i. + azoxystrobin 200 g/l a.i., picoxystrobin 200 g/l a.i. + cyproconazole 80 g/l a.i., boscalid 200 g/l a.i. + dimoxystrobin 200 g/l a.i., protioconazole 125 g/l a.i. + fluopyram 125 g/l a.i., and prochloraz 276 g/l a.i. + tebuconazole 133 g/l a.i.) on effectiveness against Sclerotinia sclerotiorum and yield. For cyproconazole 80 g/l a.i. + azoxystrobin 200 g/l a.i. and boscalid 200 g/l a.i. + dimoxystrobin 200 g/l a.i., two applications with divided and full doses were also performed. Applications at BBCH 65–67 resulted in a statistically insignificant 4% greater effectiveness against Sclerotinia sclerotiorum. All applications increased yields, but no significant difference was determined due to application timing by growth stages. Divided applications achieved the highest effectiveness, while yield was increased especially at full dosage. In practice, however, such split applications are difficult to perform.