During February, in Georgia, loblolly pine (Pinus taeda L.) stump surfaces are highly susceptible to infection by Fomes annosus up to 12 days after the tree is felled. A rapid increase in the incidence of Peniophora gigantea after 12 days apparently limited further colonization of the stumps by F. annosus. Trichoderma viride and other fungi had no apparent effect on colonization of the stump surfaces by F. annosus. Bacteria did not appear to limit colonization by F. annosus one day after the stump surface was exposed. Based upon results of this experiment, chemical stump protectants to control F. annosus on loblolly pine must provide protective action for at least 12 days. Seasonal thinning operations to control F. annosus should not be carried out closer than 2 weeks to known periods of high F. annosus infection.