PROCESSED MANURE AS CARRIER TO INTRODUCE TRICHODERMA-HARZIANUM - POPULATION-DYNAMICS AND BIOCONTROL EFFECT ON RHIZOCTONIA-SOLANI

Manure pellets produced from processed swine faeces can be used as car rier material for the biocontrol fungus Trichoderma harzianum. The ant agonist can grow and sporulate on the processed manure powder as the s ole source of carbon and nutrients. The incorporation of conidia in pe llets of the processed manure was shown to be feasible on a laboratory scale. Survival of the fungus in the pellets during storage was satis factory. The population dynamics of T. harzianum were studied using a benomyl-resistance marker after introduction of conidia into soil. The antagonist could colonize and spread through a number of non-sterile soils and was able to establish a stable population over a period exce eding 125 clays. Under sterile conditions, the propagation of T. harzi anum in soil was much greater than under non-sterile conditions. The i ncorporation of antagonist conidia in pellets was found to be essentia l for the successful colonization of non-sterile soil. In growth chamb er experiments, application of T. harzianum via processed manure pelle ts reduced damping-off of sugar beet seedlings caused by Rhizoctonia s olani in artificially and naturally infested soil. In artificially inf ested soil, T. harzianum reduced the population of R. solani and prote cted beet seedlings from damping-off 3 weeks after introduction. The a pplication of T. harzianum to naturally infested soil increased the nu mber of healthy beet seedlings more than two-fold.