How to collect a sample

Soil sample for nematodes should be taken when the soil is neither too dry nor too wet. Sampling for nematodes will vary according to the size of the area to be sampled.

When sampling a field, take a representative sample of soil from the entire field or from the area suspected of having a nematode problem. Divide fields into areas that are as similar as possible with respect to crop history, soil type, or topography. The best time to sample a field crop is immediately after harvest, or fall. Generally nematode levels are higher at this time of the year. Don’t collect samples from areas containing dead plants but take them from transition areas or areas that are still showing symptoms. Samples are usually collected with a soil probe from about 15-20 locations that represent the area. Each soil core is taken to a depth of 6-8 inches in a systematic pattern. The soil cores should be thoroughly mixed, and one pint should be placed in a plastic bag, labeled, and mailed to the NAS for analysis.

When sampling trees and shrubs, take samples from the upper 12 to 16 inches of soil directly beneath the drip line. Collect several sub-samples and mix thoroughly. Place one pint in a plastic bag, label it, and mail it to the NAS for analysis.

When nematodes are suspected in a home garden, a representative soil and root sample should be taken. Sample the top 8 to 10 inches of soil for gardens. Collect several sub-samples and mix thoroughly. Place one pint in a plastic bag, label it, and mail it to the NAS for analysis.

Nursery and greenhouse crops generally have little tolerance to damaging plant-parasitic nematodes. Contaminated substrate and/or containers could cause severe damage to theses crops. Collect a minimum of one pint of soil, including feeder roots if present. It is important to select a number of affected plants. Mix thoroughly, place one pint in a plastic bag, label it, and mail it to the NAS for analysis.

How to submit a sample

Nematodes are sensitive to heat and cold extremes as well as excessive dryness. Samples should be kept out of direct sunlight and stored in a cool location (at room temperature) until they can be submitted for analysis. Samples should be placed in a plastic bag, sealed tightly, labeled properly, and promptly submitted to the NAS for analysis.

The more information you provide about the sample, the greater the accuracy of the recommendation. Information such as crop history, soil texture, and planned crop would help in understanding the possible nematode population present in the area. A recommendation will be given in case of any probable economic loss. A NAS form should be filled out and submitted with each sample.

Pricing for this service is:

• $10 - Sample from Louisiana
• $20 - Sample from out-of-state
• $85 - Molecular ID of Meloidogyne enterolobii

Checks should be made out to “LSU AgCenter NAS”.

Samples, forms, and checks should be mailed to:

Nematode Advisory Service
302 Life Sciences Bldg. – Department of Plant Pathology
Baton Rouge, LA 70803