The Plant Pathology/Nematology Laboratory provides plant diagnostic services to the local agricultural industry and the general public. The laboratory is an important source of accurate, unbiased information on plant diseases caused by nematodes (microscopic worms) and other plant pathogens such as fungi, viruses and bacteria.
Approximately 8,000 samples are processed annually by the laboratory, with more than one-half coming from nursery stock imported into the county under quarantine. Staff also survey for problems in nurseries and other farms to prevent widespread infestations of uncommon diseases or to meet requirements for exportation of agricultural products outside the county.
Guidelines for Submitting a Sample
1. The sample should be as fresh and complete as possible; with examples of soil, roots, stem and leaves. When this is not possible, as with trees or a lawn, a picture can be helpful.
2. The sample should be representative of the symptoms, in the diseased or dying stage but not completely dead. Once a plant is dead, microorganisms that decay organic matter start to grow, making it difficult to isolate what originally caused the plant to die.
3. The sample should not be too large or too small. Pieces the size of an arm's length or smaller can be worked on in the laboratory. When a sample consists of only a few leaves or pieces of bark, it is difficult to make a good diagnosis.
4. Samples should be taken before treatment with any pesticides. Pesticides prevent growth of insects and pathogens and may prevent us from finding the cause of the problem.
Processing time for determinations:
The average time for return of the diagnosis is 1-2 weeks. Individual samples may take more or less time, depending upon the pathogens involved.
Some specialized tests require additional time, such as:
Nematode Extraction - 4 Days Minimum
Cultures - 3 to 4 Weeks
Viruses - 6 to 8 Weeks