ISSN: 2338-1345 – Vol. 2 (2): 36-40 2014 Journal online http://journal.bakrie.ac.id/index.php/APJSAFE 36 Asia Pacific Journal of Sustainable Agriculture Food and Energy (APJSAFE) Bio-efficacy of Pseudomonas fluorescens (7% WP and 5% SC formulations) against bacterial wilt disease of chilli Amitava Basu Department of Plant Pathology, Bidhan Chandra Krishi ViswaVidyalaya, Mohanpur-741252, Nadia, West Bengal, India Corresponding Author e-mail address: basuamitava1961@hotmail.com Abstract— Bacterial wilt caused by Ralstonia solanacearum is an important disease of chili crop in West Bengal. P. fluorescens was employed to manage R. solanecearum under field condition. The combined use of seed and soil treatment were most effective (0.83 to 10.82% PDI) than sole use of seed or soil treatment (3.33 to 24.98% PDI). Vegetative growth and yield of chili were also influenced through integration of seed and soil treatments with P. fluorescens 7% WP @ 10 g/kg seed + 2.5 kg/ha as well as with P. fluorescens 5% SC applied @ 10 ml/kg seed + 2.5 lit/ha . The seed treatment when followed by soil treatment showed best result in respect of fresh root weight (6.63-7.43 g), dry root weight (2.53-2.80 g), fresh shoot weight (55.45-60.23 g), dry shoot weight (24.25-26.33 g), plant height (44.83-47.53 cm) and yield (257.18-265.60 kg/ha) than control. There was no adverse effect of P. fluorescens 7% WP and P. fluorescens 5% SC on soil beneficial microbes. The products increased the root and shoot weight, dry weight of seedlings and seedling vigor index than control. The per cent root colonization in sterilized and non sterilized soil was in the range of 80-89%.It may be concluded that, the combined application of P. fluorescens 7% WP as seed treatment @ 10 g/kg seed + soil treatment @ 2.5 Kg/ha or P. fluorescens 5% SC as seed treatment @ 10 ml/kg seed + soil treatment @ 2.5 lit/ha is suggested for effective management of bacterial wilt of chili. Keywords— Chili, wilt, Ralstonia solanecearum, Pseudomonas flurorescens, biocontrol I. INTRODUCTION Chilli (Capsicum annum L.) is one of the important vegetable and annual herbaceous spice crops in India. Chilli is grown in warm and humid climate of West Bengal. The sustainability of chilli cultivation has been threatened by a number of factors. Main biotic stress is wilt caused by the bacteria. Chilli is a universal spice of India. In India it is cultivated over an area of 9.15 lakh ha with an annual production of10.18 lakh tonnes of dry chilli (Anonymous, 2007). In recent years the focus has shifted to the control of diseases using bio-control agents, which are a safe and promising alternative to synthetic pesticides. There is some evidence that endophytes can contribute to the control of plant disease (Ramesh et al., 2009). In India, limited work has been done on the isolation of endophytic bacteria viz.,Pseudomonas fluorescens (Trevisan) Migula and Bacillus subtilis (Ehrenberg.) from stem and roots of chilli seedlings (Muthukumar, 2008); Bacillus sp., P. fluorescens and Erwinia herbicola (Dye.) from chickpea (Rangeshwaran et al., 2008). The internal tissues of plants provide a uniform and safe environment when compared to the rhizosphere and phylloplane where the introduced bacterial population must compete for nutrients. These advantages envisage the use of endophytic bacteria for more successful biological control of plant diseases (Sturz and Christie, 1995). Wilt of chilli caused by Ralstonia solanacearum is one of the important serious foliar diseases of chilli crop causing maximum crop losses during the Kharif and Rabi seasons in West Bengal. Hence, an eco-friendly approach for managing this disease through application of commercially formulated bio antagonist like Pseudomonas fluorescens has been employed, under in vivo condition for reducing degradation of soil health and environmental pollution. Keeping these views in mind present study was conducted with Pseudomonas fluorescens 7% WP and Pseudomonas fluorescens 5% SC against Ralstonia solanacearum giving special emphasis on bioefficacy, phytotoxicity, antagonistic activity and effect of bio antagonist on beneficial microbes. II. MATERIALS AND METHODS The experimental trials were conducted in University Instructional Farm during the successive cropping season of October, 2012 to February, 2013 and February, 2013 to June, 2013 with a susceptible crop cultivar Bullet sown in sandy loam soil having standard spacing (50cmx50cm) and plot size (2mx2m). All standard and recommended packages of agronomical practices such as tillage, spacing, manuring and irrigation for cultivation of the crop were followed during cultivation of crop. The ten treatments i.e., T 1 =(Pseudomonas fluorescens 7% WP @ 10 g/kg seed )as seed treatment, T 2 =(Pseudomonas fluorescens 7% WP @ 2.5 kg/ha)as soil treatment, T 3 = Pseudomonas fluorescens 7% WP @ 10g/kg seed + 2.5 kg/ha (as seed and soil treatment),T 4 = Pseudomonas fluorescens 5% SC @ 10 ml/kg seed (as seed treatment), T 5 = Pseudomonas fluorescens 5% SC @ 2.5 lit/ha (as soil treatment), T 6 = Pseudomonas fluorescens 5% SC @ 10 ml/kg seed and 2.5 lit/ha as seed and soil treatment, T 7 = Streptomycin sulphate