Evaluation of Plant Extracts and Bio-control Agents Against Sclerotinia Sclerotiorum (Lib.) De Bary Causing Sclerotinia Stem Rot in Brinjal

Abstract

Brinjal is one of the important commercial vegetable crops in the world. It is grown in all over India and adapted to a wide range of climatic conditions. According to Vavilov (1928) the center of origin is Indo-Burma region. Brinjal crop is also known as eggplant according to shape and colour of fruit. It is an important source of fibers, minerals, vitamins, carbohydrates and organic acids etc., other compounds such as glycol-alkaloids and antioxidant compounds which carried a significant part in keeping good health. Brinjal is planted in three seasons first in Kharif (June-Sep), second in Rabi (Nov-Feb) and third in the month of March. Eggplant (Solanum melongena L.) is infected with many diseases. The most important disease is sclerotinia rot (white mold) caused by the Sclerotinia sclerotiorum de Bary (Lib). The symptoms first appeared on affected parts of stems become water-soaked, thick mycelium lesion (white thick mycelial Mat) on margins near the collar region and soil line of the plants. It increases inwards showed brown colour and rotting in stem. Infected brinjal plants first showed wilting in Jan. - Feb. month and month of Feb. - March. In the present investigation an experiment was conducted for the efficacy of two plant leaf extract Agele marmelos and Azadirachta indica at 5, 10 and 15% cons. and four bio-agents against S. sclerotiorum in-vitro. The maximum 85.67% inhibition of mycelium growth of pathogen was recorded in Azadirachta indica followed by 64.07% in Agele marmelos at 15% concentration after 72 hours of incubation at 25±1 0C. In bio-agents, maximum 63.70% inhibition of mycelial growth was recorded in Pseudomonas fluorescens followed by 61.85% in Bacillus subtilis. While, 52.59 % inhibition was recorded in Trichoderma harzianum and 30.00 % in Trichoderma koningii after 72 hours of incubation at 25±1 0C. Experiment was also conducted for management of sclerotinia stem rot under pot condition. The lowest per cent disease incidence 6.66% were recorded in both treatments i.e. soil application of Trichoderma harzianum (CFU 2×107/g) @5g/kg soil and soil application with Pseudomonas fluorescens (CFU10×107/g) @ 5g/kg soil + Foliar spray with Azadirachta indica leaf extract @15% after 45 days of transplanting. Maximum disease incidence 33.33% was recorded in soil application with Bacillus subtilis (CFU 6× 107/g) @5g/kg soil, foliar spray with Aegle marmelos extract @15% after 45 days of transplanting and soil application with Trichoderma koningii (CFU 2×107/g) @5g/kg soil + vermi-compost @100g/kg soil respectively after 90 DAT.