SUMMARY

Cultural practices such as tillage and crop rotation can be used as components of pest-management pro-grams. The appropriate combination of tillage systems and crops may favor the development of beneficial mi-croorganisms, preventing the spread of fungal patho-gens. A long-term field study was carried out to analyze the effect of crop management on the abundance of actinomycetes, Trichoderma spp., and Gliocladium spp., as potential biocontrol agents (PBAs), and their relation-ship with the incidence of peanut root rot caused by Fusarium solani. Soil samples were taken at sowing and harvest, and root rot incidence was evaluated at harvest. There was an inverse relationship between root rot inci-dence peanut PBA populations under no-till suggesting a possible role of PBAs in the control of F. solani, the in-cidence of root rot being low under no-till and disc har-row, associated with a high concentration of potential antagonists. However, this correlation was not observed when soybean preceded peanut, when the incidence of root rot was low despite relatively lower populations of biocontrol agents present in the soil, in comparison with maize as previous crop. Key words: biocontrol microorganisms, crop rotation, disease management, peanut root rot, tillage systems