This literature, from Clemson, shows what threshold a bentgrass golf green can tolerate in regards to the number of nematodes. If a superintendent suspects a nematode problem, a sample is sent off for what is called an assay. This is when they physically count the nematode population under a microscope from a known volume of soil, usually 100 cc or cubic centimeters. Once you know the populations, you compare your count to this chart. So looking at the results from my last assay, we found these population numbers:
Sting 3- this is the most destructive and while below the threshold, it says treating will be of value.
Lance 21- continue to monitor and this level likely won't cause a problem.
Spiral 1097- treatment will be of value and this level of numbers can cause problems.
Ring 19- well under the threshold, this number won't cause a problem.
Sting 3- this is the most destructive and while below the threshold, it says treating will be of value.
Lance 21- continue to monitor and this level likely won't cause a problem.
Spiral 1097- treatment will be of value and this level of numbers can cause problems.
Ring 19- well under the threshold, this number won't cause a problem.