Field Evaluation of Fungicide Efficacy against Downy Mildew in Luffa cylindrica

Abstract

Downy mildew, caused by Pseudoperonospora cubensis, is one of the most destructive diseases of sponge gourd (Luffa cylindrica), causing significant yield losses in cucurbits worldwide. The present field experiment was conducted during Kharif 2024 to evaluate the efficacy of seven fungicidal treatments against downy mildew under in vivo conditions. A Randomized Block Design with three replications was used, comprising the following treatments: Carbendazim 12% + Mancozeb 63% (0.15%), Azoxystrobin 4.8% w/w + Chlorothalonil 40% w/w SC (0.6%), Azoxystrobin 11% w/w + Tebuconazole 18.3% (0.15%), Aureofungin 46.25% w/w SP (0.005%), Copper sulphate 47.15% + Mancozeb 30% WDG (0.5%), Kresoxim methyl 18% + Mancozeb 54% WP (0.2%), and Potassium salt of Phosphoric acid (0.4%), along with an untreated water-spray control. Data on Per cent Disease Index (PDI), Per cent Disease Control (PDC), Area Under Disease Progress Curve (AUDPC), yield, and economic returns were recorded. Results showed that Azoxystrobin 11% w/w + Tebuconazole 18.3% exhibited the highest efficacy, with the lowest mean PDI (10.90), maximum PDC (78.16%), lowest AUDPC (237.50), and the highest yield (130 q/ha), resulting in the best benefit–cost ratio (2.05). Kresoxim methyl 18% + Mancozeb 54% WP was found at par as it showed (PDC 73.92%, yield 128 q/ha, B:C ratio 2.01). The untreated control had the highest disease severity (52.91%) and least yield (90.5 q/ha). Overall, fungicide application significantly reduced downy mildew severity, improved yield, and enhanced profitability, with Azoxystrobin 11% w/w + Tebuconazole 18.3% emerging as the most effective and economically viable option for managing downy mildew in sponge gourd under field conditions.