Research Journal of Agricultural Sciences 2011, 2(3): 655-657 Biological Management of Leaf Spot of Palak Caused by Cercospora beticola Sacc. Poornima, Yashoda R Hegde and *Jaba Jagdish Department of Plant Pathology, Collage of Agricultural Sciences, University of Agricultural Sciences, Dharwad – 580 005, Karnataka, India *Extension Education Unit, Lingsugur, University of Agricultural Sciences, Raichur, Karnataka, India e-mail: poornimaagri@gmail.com A B S T R A C T Five bioagents viz Trichoderma harzianum , Trichoderma koningii, Trichoderma viride, Bacillus subtilis and Pseudomonas fluorescens under in vitro and three biorationals like Trichoderma harzianum, Pseudomonas fluorescens and Azadiractin at 0.1% , 0.2% were tested under in vivo conditions against Cercospora beticola. Under in vitro conditions maximum reduction in colony growth was observed in Trichoderma harzianum which was significantly superior over other bioagents tested. Under in vivo conditions Pseudomonas fluorescens at 0.2% has found effective in reducing the leaf spot disease of palak with least per cent disease index. Key words: Trichoderma harzianum, Pseudomonas fluorescens, Palak, Cercospora beticola, Azadiractin Palak (Beta vulgaris var. bengalensis Hort) belonging to family Chenopodiaceae is an important leafy vegetable grown in India. Since leaves are the edible parts in palak, so the foliar diseases play an important role. The leaves of palak are rich in Vitamin A, Vitamin C and Iron. Palak being the store house of useful minerals and vitamins at the cheapest price are now a day’s considered as the corner stores of health care system due to presence of many helpful phytochemicals or phytofactors in scavenging the dreadful free radicles generated as metabolic by products in alleviating many serious diseases (Kaur and Maini 2001). They also contain high quantity of ascorbic acid, being water soluble enters tissues easily and acts to neutralize the toxic free radicals generated by metabolic process, and it is a good source of carotenoids which acts as effective antioxidant in protecting cell damage of eye, and thus avoiding blindness of aged and elderly people. This crop is severely affected by leaf spot disease caused by C. beticola leading to brown coloured spots on the leaves which hinders the market quality of the leaves. Extensive use of chemicals leads to serious environmental problems; development of resistance, since leaves are directly used for consumption application of fungicides causes harmful effects on human beings. Therefore, it becomes necessary to look for economically better and safer means of disease control. The antagnostic effect of five micro organisms under in vitro and 3 biorationals at 0.1 and 0.2% under in vivo were assayed against C. beticola. MATERIALS AND METHODS In vitro evaluation of bioagents Five biocontrol agents such as Bacillus subtilis Cohn Emend Pras Pseudomonas fluorescens Migula, Trichoderma harzianum Rifai Trichoderma koningii Oudern, Trichoderma viride, Pers. Ex. S.F. Gray, were tested against Cercospora beticola. Both, biocontrol agents and test fungus were cultured on potato dextrose agar in order to get fresh and active growth of fungus. Twenty ml of sterilized and cooled potato dextrose agar was poured into sterile petriplates and allowed to solidify. For evaluation of fungal biocontrol agents, mycelial disc of test fungus was inoculated at one end of the petriplate and antagonistic fungus was placed opposite to it on the other end. In case of evaluation of bacterial antagonist the bacterium was streaked at middle of the petriplates and two mycelial discs of the fungus were placed at opposite end. The plates were incubated at 27 ± 1°C and zone of inhibition was recorded by measuring the clear distance between the margin of the test fungus and antagonistic organism. The colony diameter of pathogen in control plate was also recorded. The percent inhibition of the growth of the pathogen was calculated by using the formula suggested by Vincent (1947). C - T I =  100 C I : Per cent inhibition C : Radial growth in control T : Radial growth in treatment In vivo management of leaf spot disease of palak by biorationals 655 www.rjas.info