BIO-CONTROL EFFICIENCY OF PSEUDOMONAS FLUORESCENS AGAINST STEM ROT OF TUBEROSE CAUSED BY SCLEROTIUM ROLFSII

Tuberose is an important crop for cut flower and decorations which is a important raw material for the production of high grade perfumes. Last few year very severely affected several pest and diseases. Recent days it was affected by stem rot of tuberose is an important disease that affects the quality of flowers, being a soil borne plant pathogen. In India among the soil-borne fungal diseases of tuberose, stem rot caused by S. rolfsii is a potential threat to production and is of considerable economic significance for tuberose. This disease causes severe damage during any stage of crop growth, and yield losses. Chemical compounds have been used to control plant disease but it has adverse effect that creates health hazards for humans and other non-target organisms. The development of safer and environmentally feasible plant disease control alternative has become a top priority. In this context, biological control becomes an urgently needs for modern agriculture. Hence, an attempt was madebio efficacy of biocontrol against for the management of stem rot of tuberose bio-control agents are seems to better management alternative methods than chemical control. The results revealed that ten isolates P. fluorescens, Pf7 has recorded effective against S. rolfsii. These isolates are further subjected to morphological and biochemical characterization of plant growth promoting activity. All the native P. fluorescens isolates tested significantly inhibited the mycelial growth of S. rolfsii However, among the isolate Pf7 showed the maximum growth inhibition of S. rolfsii up to 75.94 per cent. This was followed by the isolates Pf9 and Pf5) in the decreasing order and the least growth inhibition of pathogen was exhibited by the isolates Pf6. The mycelial growth of S. rolfsii was found to be reduced with an increase in the conc. of culture filtrates of P. fluorescens, when compared to untreated control.