Theses and Dissertations at Montana State University (MSU)

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Discovery and distribution of root lesion nematode, Pratylenchus neglectus, in Montana
(Montana State University - Bozeman, College of Agriculture, 2007) Johnson, Wendy Ann; Chairperson, Graduate Committee: Alan T. Dyer.
Root lesion nematodes (Pratylenchus neglectus and P. thornei) cause significant yield losses for wheat worldwide. To assess the prevalence of root lesion nematodes in Montana, soil samples were collected statewide in 2006 and 2007. In 2006, P. neglectus was found in 12 of the 17 counties and in 41% of all field samples surveyed. In 2007, P. neglectus was found in 11 of 15 counties and in 37% of all field samples surveyed. No P. thornei was found. For fields having root lesion nematode in 2006, P. neglectus mean population densities were 1213 nematodes/kg soil with population densities exceeding the damage threshold of 2500 nematodes/kg soil in 14% of the sampled fields. For fields having root lesion nematodes in 2007, P. neglectus mean population densities were 1303 nematodes/kg dry soil with densities exceeding the damage threshold of 2500 nematodes/kg dry soil in 13% of the samples. Damaging populations were restricted to the north central part of the state and were generally found in fields following a crop of winter wheat (p= 0.02). Stunt nematodes (Tylenchorynchus spp.) were detected in 93% and 85% of sampled fields for 2006 and 2007, respectively.