Whether you’re dealing with an insect pest infestation or an unknown pathogen damaging your beloved plants, certified WSU Master Gardeners are available to answer your questions and provide research-based guidance.
Master Gardener volunteers are trained educators who provide information grounded in university research and focused on environmentally responsible gardening practices.
Visit the WSU Lewis County Extension Plant & Insect Clinic
- Monday – Thursday
- 9 am – 3 pm
- 17 SW Cascade Ave. Chehalis, WA 98532
Remote “Ask A Master Gardener” Clinics
- Held throughout the county on the first Tuesday of each month
- 10 am – 2 pm
- Locations vary (Call for details)
Gardeners may bring plant or insect samples to either clinic location(s) for diagnosis or identification.
Preparing Samples for Identification or Diagnosis
Adapted from Spokane County Extension C083
Proper sample collection and handling are essential for accurate diagnosis or identification. Following these guidelines will help ensure your samples arrive at the clinic in good condition and helps ensure the most accurate diagnosis.
General Guidelines
- Bring the freshest sample possible.
- Store samples in a refrigerator prior to transport.
- Label the sample container with your name and date collected.
Preparing Insect Specimens for Identification
- Carefully collect insect specimens (live specimens are preferred).
- Place insect(s) in a small vial or bottle with a secure cap.
- Large adult moths or butterflies should be cushioned in a box or jar with cotton to minimize damage.
- Bring a representative sample of affected plant material, if possible.
- Place plant material in a separate container or bag.
- Store samples in your refrigerator until bringing them to the clinic.
Preparing Plant Specimens for Disease Diagnosis
If it is not practical to bring the entire plant, bring plant parts or images that show:
- Early stages of the problem
- Severely affected areas
- Healthy tissue (if available)
Collection Tips
- Place a dry paper towel in the bag with leafy samples.
- Where practical, dig up the entire plant, including the root structure.
- Avoid pulling plants, as diseased roots may be left behind.
- Wrap roots in a plastic bag separate from the rest of the plant to prevent soil contamination.
- Place the entire sample inside another plastic bag without adding moisture.
- Store in the refrigerator until transport.
Tree Diseases
Tree problems are best diagnosed by evaluating the junction between healthy and diseased tissue.
- Include twigs or limbs just beginning to show symptoms (still alive).
- Old, dead limbs are usually not helpful.
- Provide multiple photos showing:
- The entire tree
- Trunk
- Branches
- Close-up of symptoms
- Healthy vs. diseased areas
Preparing Lawn/Turf Samples for Disease Diagnosis
- Cut a turf square approximately 4 inches across and deep enough to hold soil with the roots intact.
- Leave soil intact (1-inch soil probe plugs are too small).
- Bring three to four samples, representing:
- Healthy turf
- Slightly affected turf
- Heavily damaged turf
- Store in the refrigerator until bringing to the clinic.
Preparing for Plant/Weed Identification
Plants and weeds are identified using multiple features. The most helpful parts include:
- Flowers
- Fruits or seeds
- Leaves
- Buds
- Young stems
- Roots
Because ornamental plants may have many varieties, exact identification may not be possible without flowers.
Collection Tips
- Collect as many plant parts as possible.
- Where practical, dig up the entire plant including roots.
- Place specimen in a plastic bag with a dry paper towel (do not add water).
- Seal the bag and store in the refrigerator until transport.
WSU Lewis County Master Gardeners are here to help you solve garden problems using research-based, environmentally responsible solutions. We look forward to helping you!