Microhabitat characterization of Trichoderma harzianum in natural soil: Evaluation of factors affecting distribution

In a study evaluating the effect of environment on the distribution of Trichoderma harzianum in a natural field soil, microsites composed of 50 mg soil samples were taken over 12 months and assayed for 55 different factors. Each sample was assayed for nine abiotic factors, total populations of bacteria, fungi and actinomycetes, and the presence of 42 individual fungi. Multiple logistic regression analysis was used to determine the significance of associations between these factors and the presence or absence of T. harzianum in the microsites. The presence of T. harzianum was found to vary significantly from month to month, but no regular pattern of seasonal variation was observed. T. harzianum was positively associated with the total bacterial population, and the occurrences of Aspergitlus ustus, A. tamarii, Penicillium citrinum, P. chrysogenum, and P. griseoroseum. However, it was negatively associated with the depth of the microsite and the occurrences of A. flavipes and P. miczynskii.