In vitro efficacy of fungicides for potential management of powdery mildew disease in mulberry (Morus spp.)

Abstract

Powdery mildew caused by Phyllactinia corylea is a major foliar disease of mulberry, adversely affecting leaf quality and productivity. The present investigation was undertaken to evaluate the in vitro efficacy of systemic, contact and combi fungicides on the inhibition of conidial germination of the pathogen under laboratory conditions. Five systemic fungicides were tested at 0.05, 0.1 and 0.15 per cent, five contact fungicides at 0.1, 0.2 and 0.3 per cent and five combi fungicides at 0.1, 0.2 and 0.3 per cent concentrations. The results revealed significant differences among fungicides, concentrations and their interactions. Among systemic fungicides, difenoconazole 25% EC was the most effective, recording up to 100 per cent inhibition of conidial germination with a mean inhibition of 98.89 per cent, followed by propiconazole 25% EC and myclobutanil 10% WP. Contact fungicides were comparatively less effective, though wettable sulphur 80% WP showed the highest mean inhibition (88.89%), followed by copper sulphate + lime. In the case of combi fungicides, captan 70% + hexaconazole 5% WP exhibited superior efficacy with a mean inhibition of 89.81 per cent, followed by tebuconazole 50% + trifloxystrobin 25% EC and zineb 68% + hexaconazole 4% WP. Across all categories, higher concentrations consistently resulted in increased inhibition, indicating a dose-dependent response. The untreated control showed no inhibition of conidial germination, confirming the pathogenic potential of P. corylea. Overall, the study demonstrates that triazole-based systemic fungicides and selected combi formulations are highly effective in suppressing conidial germination of the mulberry powdery mildew pathogen under in vitro conditions. These findings provide a strong preliminary basis for selecting effective fungicides for further field evaluation and integrated disease management strategies in mulberry cultivation.