Title : Disease suppressive native strains of Trichoderma spp., their low cost effective mass multiplication on agro waste substrates and shelf life enhancement on antioxidant crops
arnation in India is in a declining phase under the protected environment by the continuous interference of biotic pressure exerted due to some soil borne pathogens such as Fusarium oxysporum f.sp. dianthi and Rhizoctonia solani mainly responsible to deteriorate the plant health and cause losses upto 40 per cent annually. Due to many adverse effect of the chemicals which are widely adopted to control the diseases in general in plants, and more particularly injudicious application of fungicides has affected the environment, plant and human health. An alternative practical and safe approach is advisable to reduce the intensity of serious economically important crops. The native strains well known Trichoderma spp. have been isolated from the carnation rhizosphere from different provinces for testing their antagonistic activity under in vitro against the pathogens in order to mass multiply the best strains of Trichoderma on different readily available media. Multiplication and shelf life assessment of the native Trichoderma species on various solid and liquid substrates such as vermicompost, FYM, cocopeat, wheat straw, cocopeat, mushroom compost, rice straw including PDB and Molasses yeast extract was studied. Wheat straw registered highest colony count followed by vermicompost as agro-based substrates while in liquid substrates; PDB (potato dextrose broth) appeared superior in supporting the growth of the native isolates. Three native species namely Trichoderma viride (78.10,80.87), Trichoderma harzianum (79.03,79.47%) and Trichodrema virens (71.40,72.87%) showed highest antagonistic activity against Fusarium and Rhizoctonia pathogens causing carnation wilt and stem rot diseases by giving maximum per cent mycelia growth inhibition in vitro. However, isolates T. viride (I-10), T. harzianum (I-5) and T. polysporum (I-4) also performed better over the rest of isolates by giving mycelia inhibition within the range of 64 to 70.33 per cent. Potential Trichoderma spp. were further grown on best solid medium which revealed the highest population count in wheat straw with 10% wheat flour and 3% jaggery at pH 6.5. Natural antioxidant crops, soybean, maize and brown rice enhanced the shelf life of Trichoderma spp. under storage period of four months in solid medium. In all four native species T. harzianum, T. viride and T.hamatum and T. viride (I-10) performed better and can be used in the management of wilt and stem rot devastating diseases of carnation.