Field surveys were conducted by collecting soil samples to estimate
nematode densities in soil from winter wheat, spring wheat, spring
barley, and spring legumes (lentil, chickpea, and pea) fields during
2010 and 2011. Pratylenchus spp. were observed in 60% of sampled
fields. However, nematodes were detected in nearly all of the survey
fields in high numbers where crops were grown every year. To identify
climatic variables associated with density of Pratylenchus spp. in soil,
correlation and regression analyses were performed using climate data
of survey sites from 1979 to 2010. Fifty-seven climate variables were
significantly correlated with densities of Pratylenchus spp. All precipitation
variables were significantly positively correlated with nematode abundance. Summer maximum air temperature was negatively correlated
and winter minimum air temperature was positively correlated
with nematode densities. In addition, both years’ nematode densities
were significantly correlated with cropping intensity. Five multivariate
regression models for 2010 and seven models for 2011
nematode abundance levels were developed. The majority of the
climate variables selected in the models were related to precipitation.
Knowledge of root-lesion nematode distribution in the dryland
region of eastern Washington and associated climate variables may
be helpful to determine risk and apply management practices to
minimize crop damage