Soil Sampling

In addition to monitoring visual symptoms, collecting soil samples is an effective method to determine if you have nematodes. A general survey should be performed every year in the fall.

Soil testing should be taken as soon after harvest as possible, because many tobacco growers don't realize the severity of the crop damage caused by nematodes. In some studies, nontreated crops have looked good, but the final yield was 200 to 300 pounds per acre less than fumigated acres.

Soil samples are the only accurate way to determine if nematodes are the problem and which species need to be controlled.

Prior to taking samples, contact your county Extension agent for information concerning available sampling tools, shipment bags and proper procedures for submitting samples. Samples should not be taken when the soil is dusty dry or soggy wet.

A good sample starts with two soil cores (1 inch wide by 8 to 10 inches deep) taken for each acre of tobacco. Select samples from a 10-acre block containing a uniform soil type and cropping history. Samples should not be taken when the soil is either excessively dry or wet.

Each core should be thoroughly mixed, and then a 1-pint sample should be extracted and placed in a plastic bag and sealed. Do not allow samples to be exposed to the sun. Keep them cool (not frozen) before immediate shipment to an advisory laboratory. If possible, include living crop or weed roots and fragments in the soil sample.

When a nematode problem is suspected, take several soil cores and plant roots from within – and immediately around – a poor growth site while the crop is still growing. These samples should be prepared as described above. 

You can submit your sample to the following nematode diagnostic laboratories: