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 cotton growers don't realize the severity of the crop damage caused by nematodes. 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 from each acre of the cotton field. Select samples from a 10-acre block containing a uniform soil type and cropping history. Again, it's imperative that samples 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:

Alabama Auburn University Soil Testing Lab ALFA Building 961 S. Donahue Drive Auburn, AL 36849 (334) 844-3958 phone (334) 844-4001 fax Web site	Mississippi Mississippi State University Department of Entomology and Plant Pathology P.O. Box 5446 Mississippi State, MS 39762-9775 (662) 325-2085 phone (662) 325-8837 fax Web site
Arkansas Nematode Diagnostic Laboratory 362 Highway 174 North Hope, AR 71801 (870) 777-9702 phone (501) 671-2209 fax Web site	Missouri University of Missouri Soil Testing and Plant Diagnostic Services 23 Mumford Hall Columbia, MO 65211 (573) 882-0623 phone (573) 884-4288 fax Web site
Arizona University of Arizona Department of Plant Sciences Division of Plant Pathology and Microbiology P.O. Box 210036, Room 303 Tucson, AZ 85721-0036 (520) 621-1977 phone (520) 621-7186 fax Web site	New Mexico New Mexico State University Leyendecker Plant Science Center P.O. Box 30003, MSC 3LEY Las Cruces, NM 88003-8003 (575) 646-2281 phone (575) 646-8048 fax Web site
California For the commercial laboratory nearest you, contact your local University of California Cooperative Extension Office.	North Carolina NCDA & CS Agronomic Division 1040 Mail Service Center Raleigh, NC 27699-1040 (919) 733-2655 phone (919) 733-2837 fax Web site
Florida University of Florida Nematode Assay Laboratory P.O. Box 110820 Gainesville, FL 32611-0820 (352) 392-1994 phone (352) 392-3438 fax Web site	South Carolina Clemson University Nematode Assay Laboratory 511 Westinghouse Road, C.A.T. Bldg. Pendleton, SC 29670 (864) 656-2677 phone (864) 646-2133 fax Web site
Georgia University of Georgia Plant Pathology Nematode Laboratory 2350 College Station Road Athens, GA 30602-4356 (706) 542-9144 phone (706) 542-5957 fax Web site	Tennessee University of Tennessee Soil, Plant and Pest Center 5201 Merchant Drive Nashville, TN 37211-5112 (615) 832-5850 phone (615) 832-4936 fax Web site
Louisiana Louisiana State University Nematode Advisory Service 302 Life Sciences Building Baton Rouge, LA 70803-1900 (225) 578-1464 phone (225) 578-1415 fax Web site	Texas Texas A&M University Plant Disease Diagnostic Laboratory 1500 Research Parkway, Suite A130 College Station, TX 77845 (979) 845-8032 phone (979) 845-6499 fax Web site