Cause Pratylenchus spp., chiefly P. penetrans, are migratory endoparasites; part of the population is in the soil and part in the roots at all times.
Symptoms Stunted plants in patches in the field. Dead spots or lesions are on roots, and the root system is reduced in size.
Sampling Samples sent for nematode analysis should always include soil and roots if plants are present. Samples may be taken any time if the numbers are interpreted in relation to nematode population dynamics. In most crops, populations are relatively low through the winter and spring but increase rapidly through the summer.
Cultural control Idaho is developing resistant varieties, which may be available in the future.