Proper sampling techniques are important to ensure the best possible data. The following are guidelines to use when taking soil samples for laboratory analysis.
• Sample soil when it is moist.
• Collect all samples in A&L sample bags or a plastic bag to keep the soil from drying out.
• A minimum of 100cc. of soil or preferably 1 cup is needed for each sample to be analyzed. A larger sample is preferred if possible to allow for thorough mixing before testing is done.
• Keep samples cool. Overheating does kill nematodes. If it is impossible to send the sample immediately, refrigerate the sample until it can be shipped to the lab.
When sampling for a specific type of crop certain guidelines should be followed:
1)TURF AND ORNAMENTALS
Samples should be taken at a depth of 3”-6” or at the root level. Areas around the periphery of the damage should be sampled as nematodes move to thriving areas as the kill one area out. Make a composite sample of 10-20 locations per area sampled. This will provide a more uniform sample, as nematodes are not distributed evenly throughout the soil.
2) VEGETABLE AND FIELD CROPS
Sample should be taken at a depth of 3”-6” or at the root level. Samples should be taken at pre-plant to ensure vigorous growth of the plant. Young established plants would be more severely affected by lower nematode populations. Take about 10-20 plugs per sample to ensure a more uniform sample. Even if crop rotation is used it is important to identify nematodes that may affect a new crop.
3) TREES, WOODY ORNAMENTALS, AND VINES
Take sample far enough from the trunk to include feeder roots along with the soil sample. Several cores should be taken per area and mixed thoroughly to ensure a more uniform sample.
INTERPRETATION OF DATA
Interpretation of nematode counts is crop dependent. It is therefore very important that crop information be included when the sample is submitted for testing. If this information is not included, you will receive a more general interpretation of the results whether treatment is needed or not. It is important to remember that different plants are more susceptible to different types of nematodes.
The data will normally be reported to you on the basis of nematodes per 100cc. of soil. When requested they may also be reported per pint of soil. Root samples are analyzed on a per gram of root basis. The will vary with sample and will be clearly noted as to the per gram weight volume on the report form. Cyst nematodes may be reported as either larva per 100cc. or as eggs per gram of soil.
The report to you will include the following:
• Identification at the genus level and the common name for the nematodes found during analysis.
• Information on the type of crops known to be damaged by nematodes present in the samples.
• A suggestion whether considering the type and populations of nematode found in you sample for you particular crop.
Please note that A & L Labs will not make recommendations for the use of a particular nematicide. Further interpretation of the data can be acquired from you state or county extension agency or agricultural services. They will be able to advise you as to recommended levels and treatment for you particular crop and area of the county.
If the nematode data you receive suggests that control of a problem is warranted, there are two methods, which can be considered to achieve this goal. They are cultural and chemical control methods. A combination of the two can also be used to help eliminate future problems.
A. CULTURAL CONTROL
Cultural controls of nematode problems include crop rotation, flooding, weed control, use of resistant varieties, and use of natural enemies. Weed control is a very important yet easy way to help reduce nematode populations, as nematodes are obligate parasites and will die if there is nothing for them to feed on.
B. CHEMICAL CONTROL
Chemical control consists for two broad methods. They include fumigants and non-fumigants. Fumigants are injected into the soil and must be applied several weeks before a crop is planted. They cannot be used on an already established crop. Non-fumigants can be used on an already existing crop and are usually applied as a contact nematicide by mixing them with water.
Nematicides are highly toxic to humans. They are specifically labeled for use as to the crop type and application rates that they may be applied at. This varies state to state in many cases. If you decide to use a nematicide to treat an existing problem, you should contact your extension service, chemical dealer, or consult you states nematicide applications handbook.
Learn more about nematodes and how you can identify them.
Learn how to spot nematode damage today.
If you notice any signs of damage, have your plants tested right away.
Nematodes are considered microscopic organisms that are found throughout the soil. They are known by other names such as round worms, Nemas, eelworms, worms, and threadworms. Many varieties of nematodes live throughout the soil and they feed on fungi, bacteria, and algae. There are different varieties of nematodes that are considered parasites and feed on plant and animal life. These types can cause damage to your crops and all crops can become victim to nematode damage. Lab analysis is the only way to determine if parasitic nematodes are present.
Nematode populations are subject to the season fluctuations. The largest populations of these parasites are found when root growth is rapid. Damage to your crops is patchy where it occurs. Populations and nematode activity will decrease as the root growth begins to decline and the soil temperatures cool below 60°F or rise above 85°F. Moisture content of the soil also effect nematode populations and activity. Optimum moisture content should be 40%-80% of field capacity.
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There are two general types of nematodes that you can encounter. They include ectoparasitic and endoparasitic nematodes. Ectoparasitic nematodes are known for spending their entire life cycle outside of a host. They are able to feed by inserting a spear or stylet into the plant, which is usually done at the root system.
Some examples of ectoparasitic nematodes include:
• Stubby root
Endoparasitic nematodes spend most of their life cycle within the plants. These nematodes include:
• Root knot
Soil samples that are taken at the root will reflect populations of endoparasitic nematodes through larval populations, which have not begun to enter into the plant root system.
Symptoms of Nematode Damage
Symptoms of nematode damage will look different and vary greatly depending on the age of the plant and which part of the plant is affected. Some classic symptoms that you may find include:
• Stunted growth
• Root knots or galls
• Root lesions
• Excessive root branching
• Devitalized root tips
• Leaf, stem, flower, and seed damage
It is important to make note that knots on roots are not necessarily associated with nematode damage. Nitrogen fixing nodules appear to look much like root knot nematodes on the root. Some plants naturally produce these. It is important to keep in mind that a not does not need to be present for there to be nematodes present. If one or more of the symptoms is present, testing for nematode damage is indicated.
Nematodes can ruin your plants. Do you have any in your soil?