What testing service is offered?

Identifying the exact cause of a plant disease is rarely achieved by only viewing the disease symptoms. Disease diagnosis is most accurate when clinical tests are completed on the specimen. Our diagnostic team has extensive experience with diseases caused by pathogenic fungi, bacteria, viruses, and nematodes. We therefore are equipped to test for and identify problems caused by these, as well as abiotic (non-pathogenic) factors.

Which tests are used?

A combination of tests is used, depending on the case and the situation.

1. Culture tests involve removing pieces of diseased tissue, using sterile technique, and placing these pieces in different nutrient agars or solutions so that the pathogen could be isolated. Once a suspect organism is recovered, we use microscopes, biochemical tests, and other means to identify the pathogen and therefore diagnose the problem.
2. Molecular tests target the DNA or RNA of suspect pathogens. These molecular based tests (RPA, PCR) are designed to specifically search for and find the pathogen’s DNA or RNA, thereby confirming the presence of that organism.
3. Serological tests target certain molecules (antigens) that are present on the suspect pathogens. Tests such as ELISA specifically search for and find the pathogen’s antigens, thereby confirming the presence of that organism.
4. Other techniques such as plant incubation, grow out tests, and other methods contribute to the diagnostic process.

What materials are tested?

1. Plants: We have experience with major plant and crop groups (fruit and nut, ornamental and horticultural, vegetable, forest and landscape) and accept plant samples of any type, including new and alternative crops.
2. Soil & Rooting Media: We have extensive experience in testing soil and other rooting media for selected soilborne pathogens. We use rapid and accurate DNA-based methods (PCR, qPCR) to detect and enumerate these pathogens. Other techniques are used as well, such as culturing with semi-selective media, sieving protocols, and baiting methods.
3. Water: We use filtering, dilution plating, and other methods to search for plant pathogens in irrigation water.

What happens next?

Once a causal pathogen or responsible factor has been clinically confirmed, we can advise you on how to handle the problem. Director Steve Koike can provide information on the biology of the pathogen, conditions that favor disease, disease management and IPM options to consider, and other critical bits of information.