Influence of inoculum levels on the interaction between Glomus etunicatum and Meloidogyne javanica on bean

Abstract

The interaction of endomycorrhizal fungus Glomus etunicatumand the root-knot nematode Meloidogyne javanica, was studied in the greenhouse using different inoculum levels on the bean (Phaseolus vulgaris cv. Costa Rica). Inoculation was performed at sowing, with G. etunicatum inoculum levels of 0, 500, 1,000 and 2,000 chlamydospores per plant and M. javanica levels of 0, 100, 1,000, 5,000 and 10,000 eggs per plant. Root infection rates did not differ 15 days after inoculation of G. etunicatum. With increasing inoculum density of the nematode, plant growth was reduced, but had no effect on mycorrhizal colonization or chlamydospore production by the fungus. There was no significant increase in damage to the bean plant when inoculum levels of M. javanica exceeded 5.000 eggs per plant. Decreased nematode egg production was observed in the presence of G. etunicatum. Levels above 1,000 chlamydospores of G. etunicatum did not differ in stimulating plant growth or in having an antagonistic effect on the root-knot nematode.