Fungicides for cost-effective management of white rust-downy mildew disease complex of mustard

Abstract

White rust-downy mildew disease complex caused by Albugo candida and Hyaloperonospora parasitica has been affecting rapeseed-mustard crop globally and in India, and causing severe losses over the last few years. The study aimed to evaluate the efficacy of fungicides and their combinations for cost-effective management of this disease complex. In pooled data (2022-23 & 2023-24) among various fungicides, the combination of Metalaxyl @ 0.1% + (Metalaxyl 4% + Mancozeb 64%) @ 0.2% showed significantly minimum disease index and highest yield (14.17% and 25.74 q/ha), followed by Metalaxyl @ 0.2% (15.83% and 24.07 q/ha) and were statistically at par with each other but significantly different from other treatments and untreated control (44.17% and 16.22 q/ha) respectively. The highest net return over control (Rs. 44,976/ha) was recorded in Metalaxyl @ 0.1% + (Metalaxyl 4% + Mancozeb 64%) @ 0.2% followed by Metalaxyl @ 0.2% (Rs.37827/ha) and standard check-Metalaxyl 4% + Mancozeb 64% @ 0.2% (Rs.36898/ha). However, maximum benefit-cost ratio of 2.87 was recorded in Azoxystrobin 8.3%+Mancozeb 66.7% WG @ 0.1%, followed by Azoxystrobin 11% + Tebuconazole 18.3% w/w SC @ 0.1 (2.86) and standard check (2.85). These findings highlight the potential of fungicidal combinations for cost-effective management of white rust-downy mildew disease complex.