Vol. 12, Issue 1 (2023)

Author(s):
Betadesh, Amaresh YS, Yenjerappa ST, Ajithkumar K and Pampanna Y

Abstract:
Indian jujube or ber (Ziziphus mauritiana Lamk.) is one of the most common tropical fruit of India. Powdery mildew of ber incited by Oidium erysiphoides f. sp. ziziphi, Yan and Wang, is the most important disease that causes maximum reduction in yield and quality of ber fruits. Ber is a hardy crop which grown in arid and semi arid conditions, characterized by sandy soils, scanty rainfall (400-600 mm), thermal oscillations (5-35 ⁰C) and low relative humidity. The cultivation of ber requires the least input and care. In present investigation, In vitro efficacy of systemic fungicides revealed that the maximum inhibition of conidial germination of Oidium erysiphoides f. sp. ziziphi was observed in propiconazole (91.23%) which was on par with hexaconazole (90.92%). However, least inhibition of spore germination over control was observed in tolfenpyrad (81.09%) which was on par with azoxystrobin (81.33%). In vitro efficacy of combi fungicides revealed that, tebuconazole 50% + trifloxystrobin 25% was the most effective fungicide with maximum inhibition of 92.86 per cent. The least effective fungicide was ametoctradin 27% + dimethomorph 20.27% SC with 62.29 per cent inhibition. In vitro efficacy of various bio agents tested at different concentrations revealed that, maximum mean conidial germination inhibition was recorded with P. fluorescence (50.55%). The minimum effective bio agent was Trichoderma harzianum with 47.53 per cent inhibition. The results of the field evaluation of fungicides and bio agents revealed that among different treatments imposed, maximum disease reduction of 87.40 per cent over untreated plot was noticed in tebuconazole 50% + trifloxystrobin 25% followed by tebuconazole with 85.26 per cent disease reduction over control while the minimum disease reduction over control was shown by P. flourescens followed by B. subtilis which recorded 57.32, 55.71 per cent disease reduction over control.