Extension Search / Diagnostic Labs / Washington
Washington State University Plant & Insect Diagnostic Laboratory
The Plant & Insect Diagnostic Laboratory at Washington State University is Washington’s university plant diagnostic lab. Send it a sick plant, an insect or a weed and it tells you what it is and what to do about it, usually for a small fee.
Lab Details
Washington State University
Puyallup, Washington
- Disease diagnosis
- Insect ID
- Virus tests
- Turfgrass
- Tree wilts
- Hemp
- Photo diagnosis
Open the lab's site for fees, forms and the mailing address.
Services
- Disease diagnosis. Finds what is making a plant sick, from fungi and bacteria to cold, drought or chemical injury.
- Insect ID. Identifies insects, mites and spiders and whether they are a threat to the plant.
- Virus tests. Serological tests such as ELISA that check a plant for specific viruses.
- Turfgrass. Diagnoses lawn and turf samples.
- Tree wilts. Cultures or tests branch samples for wilt diseases such as Dutch elm disease, oak wilt or Verticillium wilt.
- Hemp. Takes industrial hemp samples. Most labs ask for your state hemp license number, and none take marijuana.
- Photo diagnosis. Looks at photos you send first, and asks for a physical sample if the photos aren't enough.
- The lab is open by appointment.
- WSU's Pullman clinic closed on December 1, 2025, so Puyallup now takes samples from across the state.
- Hemp samples need a Washington State hemp producer's license.
Not Accepted
Out of State
The lab’s site doesn’t say whether it takes samples from other states. Ask before sending one.
Sample Tips
- Call or email the lab before you send anything. What a lab accepts, and what it charges, changes.
- Send a plant that is still sick, not one that has died. Include the edge where sick tissue meets healthy tissue.
- Bag the roots and soil and tie the bag off at the stem, so soil stays off the leaves. Wrap leaves in dry paper and don’t add water.
- Mail early in the week so the box doesn’t sit in a warehouse over the weekend.
- Fill in the lab’s form completely: the plant, what you see, when it started and what has been sprayed or applied.
Not sure it’s worth a lab fee? The plant health key narrows a problem down from what you see, and your county Washington Extension office can often look at a sample free first.
Other Labs
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