Antagonists of root-lesion nematode in vertosols from the northern grain-growing region

Root-lesion nematode (Pratylenchus thornei) is a major pathogen of wheat in northern NSW and Queensland, and biocontrol is one of the major options of controlling these plant parasitic nematodes. Previous research has shown that antagonists of nematodes, such as predatory nematodes and nematode trapping fungi, were found in northern grain-growing soils (1). Certain Pasteuria species, gram-positive and endospore-forming bacteria with septate mycelium, are obligate parasites of nematodes. These bacteria have been demonstrated as effective biological control agents of nematodes such as root knot (Meloidogyne), cyst (Heterodera) and other nematodes (2). Although spores characteristic of Pasteuria have been observed on lesion nematodes previously, this is the first report on parasitism of P. thornei by Pasteuria from Australia. In this study, the parasites of P. thornei (Pasteuria, nematophagous fungi and predatory nematodes) were investigated and their distributions in northern grain-growing soils were described.