SUPPRESSION OF AN ENTOMOPATHOGENIC NEMATODE BY THE NEMATODE-TRAPPING FUNGI GENICULIFERA-PAUCISPORA AND MONACROSPORIUM-EUDERMATUM AS AFFECTED BY THE FUNGUS ARTHROBOTRYS-OLIGOSPORA

In soils of a coastal shrubland, nematode-trapping fungi may influence the distribution of the entomopathogenic nematode, Heterorhabditis he pialus. In previous studies with shrubland soil, Arthrobotrys oligospo ra was the most common fungus, followed by Monacrosporium eudermatum a nd Geniculifera paucispora, and all three fungi suppressed H. hepialus when tested individually in soil microcosms. Because shrubland soil u sually contained multiple species of nematode-trapping fungi, and espe cially A. oligospora, we quantified nematode suppression by combinatio ns of A. oligospora and G. paucispora or M. eudermatum. Fungi were add ed in the form of fungal-colonized nematodes to pasteurized soil, and nematode suppression was measured by comparing nematode invasion of wa x moth larvae. Suppression of H. hepialus tended to be less in mixed t reatments with A. oligospora than in treatments with G. paucispora or M. eudermatum alone. Population densities of M. eudermatum and G. pauc ispora were less in the presence than in the absence of A. oligospora. In contrast, A. oligospora population density was unaffected or possi bly enhanced by the other fungi.