64 Journal of Biological Control, 27 (1): 64–66, 2013 Research Note Efficacy of bioformulations against bacterial wilt of tomato caused by Ralstonia solanacearum PRANAB DUTTA Programme Coordinator, Krishi Vigyan Kendra, West Tripura, P. O. Chebri, Khowai, Tripura 799 207, India Present address: Scientist, Department of Plant Pathology, Assam Agricultural University, Jorhat 785 013, Assam, India Corresponding author E-mail: pranabd1974@indiatimes.com INTRODUCTION Bacterial wilt of tomato, Lycopersicon esculentum Mill, incited by Ralstonia solanacearum (Smith) Yabuuchi et al., (Syn. Pseudomonas solanacearum E. F. Smith) is one of the devastating diseases affecting vascular bundles of plants. The disease causes 25–75% yield loss of solanaceous vegetables in India (Rao and Sohi, 1977). The disease is very difficult to manage because of its wide host range and the exceptional ability of the pathogen to survive in the roots of non-host plants and in the soil (Kumar and Sood, 2001). The pathogen has a very wide range of host and almost all the solanaceous vegetables are susceptible. In India, plant species belonging to 37 families are attacked by bacterial wilt pathogen (Shekhawat et al., 1992). Perusal of literature indicated that considerable attempts have been made to manage the disease in various crops and in different places with the use of host resistance, changes in cultural practices, bioagents and chemicals (Dubey et al., 1996; Biswas and Singh, 2008; Kishore et al., 1996). However, the disease is still a major problem in tomato cultivation. Hence, the present study was carried out to find out most effective control measure against the bacterial wilt of tomato under the agro-climatic conditions of Tripura where severe outbreak of the disease occurs in tilla (hillock) land of sandy loam soil. ABSTRACT: Bacterial wilt of tomato caused by Ralstonia solanacearum is the dreaded diseases causing severe yield loss (25-75%) in farmers’ field. A field experiment at demonstration farm of KVK West Tripura was conducted for the evaluation different chemicals, botanicals and bioformulation against the disease. The study revealed that all the treatments were significantly effective over the control. However, soil drench with antibiotic @ 100 ppm was found best with lowest (23.6%) disease incidence and highest yield (228.2 q/ha). This was followed by copper oxychloride in terms of disease incidence (28.4%) and Biofor Pf in terms of yield (220.6 q/ha). Highest disease incidence (78.67%) with lowest yield(86.5 q/ha) was recorded in control plot . KEY WORDS: Bacterial wilt, management, tomato (Article chronicle: Received: 17-09-2013; Revised: 10-01-2013; Accepted: 18-02-2013) The present investigation was carried out in the Instructional cum Demonstration Farm of Krishi Vigyan Kendra, West Tripura during the winter crop season of 2008-09 and 2009-10 (October to April). Tomato genotype viz., Arka Vikash was used in this experiment. The experiment was set up by transplanting 20 day old seedlings in a bacterial sick plot using RBD design of four replications to compare 5 treatments (including control). The plot size was 2.5 x 5 m 2 with 60 x 45 cm 2 spacing between rows and plants. Fertilizer schedule was FYM @ 10 ton/ha, NPK @ 120:80:60 Kg/ha, half of N and full doses of FYM, P 2 O 5 and K 2 O was applied as basal and the remaining half of N was top dressed 30 days after. One weeding was done at 20 days after transplanting. The plants were irrigated 4 times at an internal of 15 days. The number of plants wilted per plot was recorded starting from 15 days after transplanting and then at 15 days intervals following the method of Mew and Ho (1976). Bacterial ooze test was conducted on wilted plants to confirm the disease. Four treatment combinations were tried viz., 2 chemicals (Plantomycin @ 100 ppm and copper oxychloride @ 0.3% w/v), 2 botanicals (Hing / Asafoetida and Turmeric @ 1:5) and a bioformulation (Biofor Pf, a Pseudomonas flourescens and Trichoderma harzianum based bioformulation developed by Assam Agricultural