Efficacy of Pseudomonas fluorescens against bacterial blight and leaf spot diseases of cotton (Gossypium hirsutum)

Abstract

An experiment was conducted during rainy (kharif) season of 2006 – 09 to study the efficacy of Pseudomonas fluorescens against foliar diseases of cotton (Gossypium hirsutum L.). Pooled data of 3 years showed that seed treatment with P. fluorescens Pf 1 @ 10 g/kg seed and foliar spray @ 0.2% at 30, 40, 50, 60, 70, 80 and 90 days after sowing gave maximum control of bacterial blight (40.25%), Alternaria leaf spot (35.16%), Helminthosporium leaf spot (50.50%) and Myrothecium leaf spot (45.37%) and recorded maximum yield of 1.46 tonnes/ha against 1.19 tonnes/ha in control. Highest benefit:cost ratio of 1.92 was obtained with seed treatment with P. fluorescens Pf 1 @ 10 g/kg seed + 7 foliar sprays @ 0.2% at 30, 40, 50, 60, 70, 80 and 90 days after sowing and seed treatment with P. fluorescens Pf 1 @ 10 g/kg seed + 5 foliar sprays @ 0.2% at 30, 50, 70 and 90 days after sowing recorded 1.87 benefit:cost ratio as against 1.66 in 7 water sprays. Seed treatment with P. fluorescens Pf 1, followed by 0.2% foliar spray of the same at 10 days interval starting from 30 days after sowing is cost effective in managing important foliar diseases, viz bacterial blight and leaf spots caused by Alternaria, Helminthosporium and Myrothecium.