Virus Testing for Your Garden 2021

Yellow veins indicate virus

With the cooperation of Professor Pappu at Washington State University (WSU) and the support of the Scheetz-Chuey Foundation, the Dahlia Resource Center at WSU will test our dahlias for virus again this year.

The testing project is driven by two key observations.  First, dahlias that are tested and found to be free of virus produce tubers and plants in the subsequent year that have a significantly lower incidence of virus than untested plants.  Second, dahlias that test positive for TSV produce tubers and plants in the subsequent year that virtually always have virus! 

There are three critical steps required to reduce the presence of viruses in our gardens.  The first is to acquire clean stock whenever possible.  The local club project and the vendor testing project, discussed below, target making clean stock more readily available.  Second is to remove plants with virus from your garden.  Remove and destroy plants with suspicious foliage (usually yellowing veins).  “If in doubt, throw it out.”  Third, avoid transferring virus from plants with virus to clean plants by disinfecting your cutters, in particular, after you finish working on each plant.  “Clean Between!”  Procedures for disinfecting your tools are available in the “Understanding Virus in Dahlia” page on this website


Subsidized Tests for ADS Societies

The objective of this project is to increase the availability of clean stock within ADS Participating and Affiliated Societies across the USA.  The clean plants that are identified can provide tubers that will serve as the source for propagating clean plants for the following year’s club sales.  With the support of the Scheetz-Chuey Foundation, the ADS will cover half ($150) the cost of testing the basic set of 30 samples for each ADS society.  It is our experience in the Midwest Conference Spring Auction that plants grown from clean stock command a substantial premium.  The costs for the testing were readily recovered in the sales of those special plants.

The key first step for your society to identify a project coordinator.  That chairman should apply for the program as soon as possible.  A schedule for sending samples will be supplied to the club representative.  The instructions for applying for the program and the forms for sending the samples are available below.


Free Testing for Vendors

Test slots have been reserved for dahlia vendors who choose to take advantage of a free and confidential testing program.  With the support of the Scheetz-Chuey Foundation, the ADS will cover the costs of the authorized tests.  Applications for participation in the program will be accepted until June 30. 


Open Testing

The program for the testing of sets of 30 or more samples for $10 per sample may be available again this year if the testing load on the foregoing projects fall below expectations.  Please contact Ron Miner at to determine if you can submit samples.


Turn-Around Time for Results

We anticipate that the turnaround time to receive the test results will be approximately one month.  Be aware, however, that the time will depend on the number of samples submitted. 

In any case, you should be prepared to store tubers from test plants before you know the virus results.  That will require careful tracking of the tubers from the test plants in storage.

Professor Pappu and his group at WSU and in the Dahlia Resource Center will run the (sophisticated!) tests as quickly as possible.  However, accuracy will continue to be more important than speed in generating the test data.


Links for Applications, Instructions, and Submission Forms


Application for Participation pdf
Instructions  pdf
Submission Form docx or pdf
Sample Tags docx or pdf

ADS Participating and Affiliated Societies:

Application for Participation pdf
Instructions pdf
Submission Form docx or pdf
Sample Tags  docx or pdf

Open Submissions:

Instructions  pdf
Submission Form  docx or pdf
Sample Tags  docx or pdf