Bob Mulrooney, Extension Plant Pathologist; firstname.lastname@example.org
The fall is generally the best time to sample for nematode populations in vegetables and field crops. After harvest is complete but before any fall tillage is the best time for taking survey samples. With the very dry conditions, however, I would delay taking fall nematode samples until we get some rain. Samples taken from very dry soil may not be representative of what is present in the field.
One other observation is that nematode soil samples should not represent any more than 20 acres. Nematodes are not uniformly distributed in the soil and it would be easy to miss significant numbers if a single sample of 20 soil cores represented a large acreage. I am not trying to generate more work, just better information on which to make an informed recommendation.