Testing for Endophytes

OSU Seed Laboratory



David Stimpson, PhD

3291 SW Campus Way

Corvallis, OR 97331-3801

Tel. 541-737-4464

Fax 541-737-2126


  • Please contact the Seed Laboratory for sampling and packaging instructions.
  • Pest and Disease (dry seed inspection)
  • Endophyte test (chemical/immunoblot assay) seed and/or tillers
  • Broom-rape (Orobanche minor) in Red Clover and other species.
  • The laboratory operates on its fee income. As costs rise for supplies, equipment, and personnel, it is necessary from time to time to adjust the fee schedule. For current prices please see the following website:https://seedlab.oregonstate.edu/testing-services/testing-fees

Endophyte Service Lab

We test feed materials for ergovaline, lolitrem B, and ergot alkaloids. For some test types, rush processing is available. Clinical clients can submit samples by express mail or FedEx. Clinical clients should contact the laboratory by phone or email and we will advise in proper sample collection and submission.

The cost is $50 U.S. Funds/sample/assay.

Checks should be made payable to: Oregon State University

Clients may choose to be billed rather than to send payment with sample.

Sampling Tall Fescue and Perennial Ryegrass for Endophyte Toxin Analysis

Concern about endophyte-infected tall fescue and perennial ryegrass seed straw has generated repeated questions about samples of straw for endophyte testing. Straw samples are analyzed for toxin content, not for endophyte presence. These chemical analyses are only as good as the straw sample provided. In other words, a toxin test will accurately represent a lot of straw only if the sample is truly representative. The following the guidelines will ensure that samples are as representative as possible.

Use a Core Sampler Commercial forage samplers are available through farm supply sources. Your county Extension agent can help you locate a supplier. Attach a core sampler to a brace or half-inch drill for easy sampling. Ideally, the sampler should have an exterior diameter of 0.5-inch and a sample length of at least 12 inches. Minor deviations from these measurements are acceptable.

Sample a bale by centering the core sampler in the end of the bale and drilling horizontally. Take at least 20 cores (one per bale) for each lot of hay.

A lot of straw should represent straw from one variety, harvested from the same field. If two lots of straw are in a stack, sample them separately. A truckload of straw may be considered a lot if there is no information to the contrary.

Sample at Random Bales within a lot of straw should be sampled at random. “Random” means that you have no precise reason for selecting or rejecting a specific bale to sample. Here are two ways to guard against biasing. First, sample every fourth or fifth bale, going around the stack (or truck) or driving down the row in the field. Or, take at least five random samples from each of the four sides of the stack.

Mailing Place the entire sample in a polyethylene freezer bag and seal it tightly. Be sure to label the sample with your name, telephone number, sample identification, and the type of assay you want the lab to perform. Either write this information directly on the bag using a permanent marker pen, or write it on a piece of paper (a business card is ideal) and enclose the paper with the sample. Commercial clients should use the website to generate appropriate labels for their samples.

To take a pasture sample, randomly select 20 separate sites within the pasture. At each site clip a handful of grass just above the ground. If your animal typically pulls the plant up by the roots and eats the entire plant, you may wish to pull up a handful of plants at each site. Otherwise, clipping plants at ground level will be sufficient. It is best to air dry your sample out of direct sun light before shipping. If your sample is not dry, it is not acceptable for testing and should not be submitted.

Proper samples should be submitted to the following address:

139 Oak Creek Building

Endophyte Service Laboratory

College of Agricultural Sciences

Oregon State University

Corvallis, OR 97331

The laboratory phone number is (541) 737-2872 if you have any questions.