Studies on Variability of Leveillula taurica (Lev.) Arn. Causing Chilli Powdery Mildew and its Management.
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Date
2018-07
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University of Agricultural Sciences, Dharwad
Abstract
Laboratory and field experiment were conducted at Department of Plant Pathology, College of Agriculture and Main Agricultural Research Station, Dharwad to study the variability and management of chilli powdery mildew involving survey, survival study of pathogen and yield loss estimation during kharif, 2017.
The maximum disease severity was noticed in Dharwad district (62.03%) and the least severity was noticed in Belagavi district (22.01%). Among the 24 isolates morphological variability observed in terms of shape, size and colour of the conidia, branching and length of conidiophores. Viability of conidia of Leveillula taurica was observed up to 140 days under freeze condition and least under field condition up to 84 days. Higher amount of total sugars and non- reducing sugars was recorded in diseased leaves but higher amount of phenols and reducing sugars was recorded in healthy leaves.
The observations on yield loss estimation revealed that, three sprays of Sulphur 80% WP (0.3%) were found to be effective in reducing disease severity (76.44%),
increasing yield (9.54 q/ha) and cost benefit ratio (1: 3.03). Yield loss of 50 per cent was noticed due to powdery mildew in unsprayed plots.
Maximum germination of conidia was observed in 2 per cent sucrose solution
(50.78%) at 24 hr after incubation. Azoxystrobin (0.1%), Bacillus subtilis (1%),
nimbicidin (0.5%) were found effective with higher per cent inhibition of conidial
germination among different fungicides, bioagents and botanicals respectively
evaluated under in vitro condition. The observations on integrated management of
powdery mildew revealed that, three sprays of azoxystrobin (0.1%) at 12 days interval
was most effective with highest yield (13.25 q/ha) and cost benefit ratio(1:3.33).
Azoxystrobin (0.1%) was most effective in managing powdery mildew of chilli.