Bioefficacy of Fluoxapiprolin (30 G/L) and Fluopicolide (200 G/L) SC on Cucumber Downy Mildew

Abstract

Cucumber downy mildew, triggered by Pseudoperonospora cubensis, is a harmful disease and a primary limitation in cultivation, leading to considerable damage and a substantial decrease in fruit output. The efficient management of crops is necessary from the initial phase of disease development, which can be guaranteed by appropriate fungicides. The field experiment took place in Kharif 2023 and Rabi 2023 at the College of Agriculture, Gangavathi. The treatments were applied as foliar sprays within a randomized block design featuring replicated plots. Fungicidal sprays were started right after downy mildew symptoms appeared in the primary field, and standard horticultural methods were adhered to during the entire cropping season. The test fungicide Fluoxapiprolin 30 g/L + Fluopicolide 200 g/L SC was applied as foliar spray when the initial symptoms of downy mildew appeared on the crop. Disease severity was recorded as per cent disease index (PDI) from five randomly selected plants per plot before spraying and at 7 days after each spray, using a 0-9 standard disease rating scale. During Kharif 2023, the lowest mean PDI (6.28%) was recorded with Fluoxapiprolin 30 g/L + Fluopicolide 200 g/L SC @ 625ml/ha with maximum fruit yield of 16.10 t/ha followed by Fluoxapiprolin 30 g/L + Fluopicolide 200 g/L SC @ 500ml/ha (7.20%) with fruit yield of 16.00 t/ha and highest disease was recorded with untreated control (36.13%) with lowest yield of 10.10 t/ha. Similarly, during Rabi 2023, The lowest mean PDI (5.69%) was recorded with Fluoxapiprolin 30 g/L + Fluopicolide 200 g/L SC @ 625ml/ha with maximum fruit yield of 16.75 t/ha followed by Fluoxapiprolin 30 g/L + Fluopicolide 200 g/L SC @ 500ml/ha (6.63%) with fruit yield of 16.50 t/ha and highest disease was recorded with untreated control (29.76%) with lowest yield of 11.20 t/ha. These results indicated that foliar spray with Fluoxapiprolin 30 g/L + Fluopicolide 200 g/L SC @ 500 ml/ha to 625ml/ha once at disease initiation stage and repeated twice at 7 days interval found highly effective in managing the cucumber downy mildew and which helps in good crop growth, resulted in higher yield.