Management of early blight of Potato (Solanum tuberosum L.) incited by Alternaria solani (Ellis & Martin) Jones & Grout through fungicides

Abstract

The efficacy of some combination fungicides like fenamidone 10% + mancozeb 50% WDG, metiram 55% + pyraclostrobin 5% WG and cymoxanil 8% + mancozeb 64% WP along with commonly used fungicides viz., dimethomorph 50% WP, fosetyl Al 80% WP, mancozeb 75 WP, metalaxyl 8% mancozeb 64% WP, captan 70% + hexaconazole% WP and carbendazim 25% + mancozeb 50% WS were tested against early blight of potato cv. Kufri Pukhraj at Agricultural Research Station, Ladol, Gujarat. A variant with no application of fungicide was used as a control. All the treatments reduced the disease intensity significantly as compared to untreated check. The data on PDI of early blight of potato was recorded periodically at 40, 50, 60 and 70 days after sowing with consecutive three spray of fungicides at 15 days interval and was found low to moderate in range (12.94-20.64%). The lowest per cent disease intensity (PDI) 12.94 was observed in case of fenamidone 10%+ mancozeb 50% WDG @ 0.2% treatment (2.5 gm/l) and it was at par with the treatment of metiram 55% + pyraclostrobin 5% WG @ 0.2% (2 gm/l) and cymoxanil 8% + mancozeb 64% WP @ 0.25% (2.5 gm/l) with its POI per cent 14.04 and 14.94, respectively. It significantly reduced the early blight as compared to control. Similarly, the highest yield of potato tubers was recorded in fenamidone 10%+ mancozeb 50% WDG@ 0.2% (2.5 gm/litre) against early blight with 60574 kg/ha followed by metiram 55% + pyraclostrobin 5% WG @ 0.2% (2.0 gm/litre) and cymoxanil 8%+ mancozeb 64% WP@ 0.2% (2.5 gm/litre) with its yield 56778 and 50352 kg/ha, respectively. Thus, it can be said that combination of protective fungicides effectively suppressed pre- as well as post-infection activity and inhibited sporulation and/or restricted lesion expansion of early blight pathogen. Also found increase in the yield of potato as well.