effect of different organic substrates and carbon and nitrogen sources on growth and shelf life of trichoderma harzianum

nine organic substrates viz., rice grains, sorghum grains, wheat grains, millet grains, wheat straw, rice husk, cow dung, sawdust, and poultry manure were used for mass multiplication of trichoderma harzianum. of these,sorghum grains followed by millet grains were the best substrates. the poultry manure appeared to be the most unsuitable substrate, whereas rice grains, wheat grains, wheat straw, and rice husk performed moderately well. sucrose was the best carbon source and supported the highest colony growth of t. harzianum on czapek’s agar plates. similarly, ammonium nitrate at 3,000 ppm appeared to be the most suitable nitrogen source and produced the highest colony growth as well as abundant conidia. a combined use of sucrose at 30,000 ppm as carbon source, and ammonium nitrate at 3,000 ppm as nitrogen source significantly enhanced the mycelial growth and conidial production by t. harzianum in wheat straw, rice husk, and millet grains, whereas, in sorghum grains and rice grains, the addition of carbon and nitrogen sources showed negative effect on sporulation of t. harzianum. studies on shelf life of the inocula multiplied on various substrates showed that the populations of t. harzianum on all the substrates achieved the peak at 60-75 days incubation period and declined gradually thereafter. however, even after 330 days, the populations were greater than the population at 0-day. at 345-360 days interval, population was found to be less than the initial population at 0-day.