POPULATION RESPONSES OF TARGET AND NONTARGET FOREST SOIL ORGANISMS TO SELECTED BIOCIDES

Oxytetracycline-penicillin (combined), captan, fumigillan and dimethoate-carbofuran (combined) were applied to forest soils to test their effects on soil populations of active and total bacteria, active and total fungi, protozoa, nematodes and microarthropods. All biocides significantly reduced the populations of target organisms, except dimethoate-carbofuran, which failed to reduce the number of microarthropods. All biocides also affected populations of non-target organisms. Oxytetracycline-penicillin reduced lengths of active hyphae. Captan reduced nematode and bacterial numbers. Fumagillin reduced active hyphal lengths and the number of nematodes and total bacteria. Dimethoate-carbofuran reduced active hyphal lengths and the number of active bacteria.