ABSTRACT
Trichoderma harzinuam was found to parasitize Cephalosporiurn acremonium, the incirant of Cephalosporium-wilt disease of gain sorghum. Inhibition and death of the host hyphae were: brought about by close contact. T. harzianurn penetrated and grew within the hyphae of the host, C. acremonium. Abundant sporulation of T. harzianum occurred on the colony of the host. Culture filtrates obtained from T. harzianum isolates showed a toxic effect on C. acremontium mycelial growth and inhibited it by more than 35% compared with the control. Sucrose and glucose [as carbon sources], ammonium tartrate and ammonium nitrate [as nitrogen sources], acidic pH and low C/N ratio were the most favourable factors for mycoparasitism. Based on a preliminary pot experiment, the possibility of controlling the disease by soil inoculationwith T. harzianum is suggested. Adding T. harzianum to C. acremonium infested soil decreased the incidence of the disease significantly
Subject(s)
AcremoniumABSTRACT
Fourteen Trichoderma harzianum Rifai isolates were tested, either singly or in mixtures to control damping-off and root rot [Rhizoctonia solani Kuhn], stem rot and root rot of beans [Sclerotiuim cepivorum Berk] and white rot of onion [Sclertiuim cepivorum Berk]. A synergistic effect in controlling these diseases was obtained by using mixtures of T. harzianum isolates. Barley grains supplemented with gliotoxin fermentation medium + I prodione [500 ppm.]-+ streptomycin was the best food-base for T. harzianum establishment soil. A negative correlation between the incidence of dampingoff and root rot, and amount of T. harzianum inoculum was noticed. Also severe reduction in the number of S. rolfsii sclerotia was correlated with increases in the number of T. harzianum propagules in the soil. Beside the effect of T. harzianum in protecting host plants from the aforesaid diseases, it cause a significant increase in fresh weight of treated plants