1. Exotic plant disease surveys

This component reflects a cooperative relationship between the Nevada Department of Agriculture (NDOA, the Cooperator) and the United States Department of Agriculture (USDA), Animal and Plant Health Inspection Service (APHIS), Plant Protection and Quarantine (PPQ). It has the mission-related goals, objectives, and anticipated accomplishments. In general, USDA-APHIS provides partial financial support for part-time workers salary and operational costs. The state plant pathologist coordinates and executes the survey projects. Surveys target devastating pathogens or nematodes that have high risk of introduction to the United States. Annual survey ensures early detection and eradication of risky pathogens. Survey data benefit issuing of state and federal phytosanitary certificates and facilitate expansion of overseas markets to the Nevada growing products.

2. Plant disease inspections and quarantine

This component includes 1) annual inspection of onion and garlic fields for white rot disease and stem bulb nematode; 2) potato and alfalfa field inspection for seed certification purpose, 3) Nursery inspections for potentially introduced plant diseases, and 4) other inspection for federal or state phytosanitary purpose. Regular inspection of agricultural fields and commodities ensures real-time monitoring and eradication of important plant diseases that have significant impact on agricultural production and commodity quality. It protects all growers and other entities from economic losses caused by plant diseases.

3. Laboratory services

The plant pathology program operates the Plant Pathology Lab, the Nematology Lab, and the diagnostic greenhouse facility. The Plant Pathology Lab has advanced equipment and techniques to conduct a broad range of testing for plant pathogenic fungi, bacteria, viruses and nematodes. The Nematoogy Lab is fully equipped and provides nematode extraction and identification services. The Diagnostic Greenhouse is an added asset to our laboratory and facilitates virus and nematode detection, pathogenic tests, disease quarantine, and other diagnostic purpose. Laboratory operations are aimed to maintain and enhance the following functional components:

1. Diagnosis of plant health problems or disorders for statewide clientele.

2. Detection of specific exotic plant pathogens as a part of national CAPS and pest detection program.

3. Analysis of specific plant pathogens for certification or phytosanitary purposes.

4. Development and optimization of diagnostic protocols for regulated and other important plant diseases.

5. Investigations of causes of new or unknown plant health problems.

4. National Plant Diagnostic Network (NPDN) and outreach

NPDN is a functional national network integrating all diagnostic laboratories from land-grant universities, state departments of agriculture, and USDA-APHIS. It promotes the early detection of high risk, exotic and emerging plant pests through enhanced diagnostics, education, and response exercise scenarios. Nevada Department of agriculture (NDOA) takes a leading role in coordinating NPDN program in the state by training first detectors and conducting diagnosis of exotic pests and diseases. The first detector can be anyone who, in the course of their duties, has a pest/disease of concern or who is in the position of noticing an unusual outbreak. A trained first detector is registered formally as a NPDN first detector and performs his/her duties by watching out any unusual plant health problems and/or submitting suspicious samples to the state diagnostic labs. Every year, NDOA in conjunction with the University of Nevada Cooperative Extension conducts either face to face or online training to new first detectors. All first detectors receive NPDN first detector newsletters, state/national pest alerts and updates. Additional training is also provided to specific groups or entities to promote public awareness of important diseases and pests. Samples submitted by first detectors are processed in the laboratory with a high priority to identify potential exotic plant pathogens. Quarantine and eradication may take place if any exotic pathogen is positively identified.

1. Providing services to general public

The plant pathology laboratory provides diagnostic services to public clients, including growers, nurseries, landscape professionals, consultants, pest control applicants, and homeowners. The laboratory accepts physical samples and electronic images for diagnostic purpose. Inquiries by phone or email are generally responded promptly until clients are completely satisfied. For walk-in clients, consultations are provided in addition to examining the carried-in plant samples. All plant samples are stored in a refrigerator immediately after arrival, logged into our database, and examined or tested within two days. After completion of diagnostic process, formal report is generated from our database and sent to clients either a hard copy or an electronic copy.

2. Conducting a disease survey

Each survey for a plant disease or nematode has a standard guideline. Most of our surveys are part of USDA-APHIS PPQ Cooperative Agricultural Pest Survey (CAPS) program. The survey includes financial and personal planning, field sampling, laboratory testing, final confirmation, data entry and reporting. Prior to a survey for a specific organism, both field protocol and laboratory protocol are developed. After laboratory testing, final confirmed data are entered into the NAPIS database and the NPDN database. Narrative report for each project is sent to the State Plant Health Director (SPHD). The survey data are used to determine the occurrence of specific plant pathogens, which support state and national plant disease management and commodity export endeavor.

3. Field inspection and sampling

We inspect fields for quarantine diseases and/or for phytosanitary purpose. Depending on the type of plant disease, each field is inspected in a pattern to maximize the detection of diseased plants. Samples of plant tissue or soil from suspected diseased plants are taken and brought into our laboratory for confirmation. Positive identified plants or locations are marked and GPS recorded. Eradication or treatment procedures are ordered under the authority of NRS 554, 555, or 587 when appropriate.

4. Sample handling

All samples either collected or submitted are handled carefully to ensure their freshness and integrity. Plant samples collected from fields are immediately placed on ice and maintained in a cooler during the transportation. Samples received from inspectors or public are immediately placed in a refrigerator. Each sample is entered into our sample log-in sheet and assigned a lab number for tracking. If a sample is not in a good condition or is not representative of the problem, clients may be asked to send additional samples. After diagnosis and reporting findings to clients, samples are then destroyed properly if any dangerous pathogen is found or disposed as a regular trash if no pathogen is found.

5. Laboratory procedures

Laboratory diagnostic procedures vary significantly in terms of pathogen types, sample conditions, and costs. As a regulatory laboratory, we conduct Disease Detection/Diagnosis/Identification (DDDI) in a standard format starting from basic procedures to higher levels of determination. When a sample is received, microscopic examination will be conducted to determine the presence of potential insect/mite infestation and diagnostic fungal fruiting bodies. Further procedures include plating of plant samples on general or selective culture media, serological tests, and DNA-based tests. For nematode samples, extraction of nematodes from soil and plants are performed. Grow-out tests in greenhouse or incubation of samples in a humidity chamber (pathogen induction) are also performed to determine the causative pathogens. The following technical approaches are used alone or in combination to determine the cause of any given plant health problem or to identify an obtained pathogenic microorganism.

• Induction of plant pathogen from specimen

• Bioassay in greenhouse

• Microbiological / morphological approaches

• ELISA & serological tests

• Fluorescent labeling

• Nested PCR detection

• Real-time PCR detection

• DNA sequencing and bioinformatics analysis

• Nematode extraction and identification

6. Scientific professionalism

With each DDDI activity, scientific testing is ensured by searching relevant scientific literatures and well designed laboratory protocols. Quality control tests are always included to ensure the quality of Data. We use only the actual findings and objective statements in our report.

7. Reporting

A written report of the diagnosis/analysis and recommendations is sent to the submitter when the testing is com¬pleted. Additional information on disease management is also provided with the report. For survey projects, formal reports are sent to funding agencies. All data are reported to NPDN national repository.  Contact Us

Other Links

• WPDN
• USDA
• APS
• US Plant Protection and Quarantine
• SON (Society of Nematologists)

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