Understanding Virus in Dahlia


New tri-fold brochure  Virus in Dahlias – Be Part of the Solution now available.
Learn more.


Our ability to detect and to control viruses in our dahlia gardens has improved dramatically over the last 20 years.  Washington State University (WSU) has been at the heart of the research work that has made that progress possible.  The American Dahlia Society has also been an integral part of the work at WSU throughout that period.  Most recently, the Scheetz-Chuey Foundation has made it possible to sponsor a permanent Chair for Dahlia Research and Development at WSU and to create a Dahlia Resource Center there.  These investments are providing the bases for a rapid increase in our understanding of dahlia viruses and of the best ways to control virus in our gardens.

An ADS Virus Team is working with WSU to coordinate virus testing in member dahlia gardens and in communicating test results and control techniques to our dahlia growers.  With the cooperation of Professor Pappu at WSU and with the financial support of the Scheetz-Chuey Foundation, the testing of field dahlia plants started in 2015 and that work has grown steadily in volume, importance, and effectiveness over the years since. 


Controlling Virus in Your Dahlia Garden

Perhaps the most important practical result achieved to this point has been the development of procedures to minimize the transfer of virus between clean and infected plants.  See the new brochure and the article on that topic below: Virus in Dahlias – Be Part of the Solution.  The key to success follows from adopting the habit of disinfecting the tools you use in managing your dahlias.


Start with Clean Stock

Another key conclusion evolving in the garden testing was on the importance of starting with clean plants.  The March, 2019, ADS Bulletin article on Virus Results – 2018 demonstrates that a combination of virus-free stock and rigorous disinfecting practices can produce very low incidence of virus in your garden.  Much of the current and future testing work is focused on improving our ability to routinely acquire clean stock.  Until sources of clean stock become more readily available, it is very important that you retain only the healthiest looking plants for future stock.


Control Thrips

The research at WSU has shown that thrips are an important source (technically, “vector”) for moving dahlia viruses among dahlias and between dahlias and many other virus host plants, like weeds!  Two articles in the March, 2019, ADS Bulletin describe the role thrips play in that process, Thrips Control, and in Integrated Pest Management (IPM) approach to minimize thrips in our gardens: Using IPM Methods for Dealing with Major Insect Pests of Dahlias.


Dahlia Resource Center

The new Dahlia Resource Center at WSU will become an increasingly important vehicle both for informing dahlia growers about improvements in virus control and for guiding the direction of future research efforts.  Dr. Moyo summarized the objectives of the Center in the December, 2018, ADS Bulletin.  Current efforts include examining procedures for meristem tip culture to grow clean stock from contaminated plants.

Dr. Prabu Gnanasekaran has been appointed to the position of Director of the Dahlia Resource Center.  We will be hearing more from him in future articles.

Progress Reports

Perhaps the easiest way to follow the progress of the practical virus work in our gardens is to read the Virus Results – 201x articles that appear in the March Bulletins.  The articles summarize the previous summer’s virus projects and results.


Hide and Seek

Be aware that there are still more questions than answers in our efforts to understand dahlia viruses.  Linda Taylor’s article on Hide & Seek Virus Testing addresses that issue specifically.  One important area of lack of knowledge is the differences in the behavior of the six different viruses we’re following.  See, for example, the end of the Virus Results –2018  article in the March 2019 Bulletin.

Following are the articles and presentations that summarize our work on viruses in dahlias.



If you are interested in helping the ADS fund this project, give your gift today.  Please indicate on your check or donation that you would like to fund the WSU Virus project.  Please show your support and give a gift.  Send your donation to:

ADS/WSU Virus Project
38430 Piggott Bottom Road
Hamilton, VA  20158

or donate via Paypal:



2020 Documentation


2019 Documentation

DSO 30 - Virus 0ArticleSep '13ADS Bulletinview
Virus Project UpdateArticleSep '13ADS Bulletinview
Update on Tissue Culture TestArticleSep '13ADS Bulletinview
Virus Testing 2019ArticleJune '19ADS Bulletinview
Virus Results - 2018ArticleMar ' 19ADS Bulletinview
Integrated Pest ManagementArticleMar '19ADS Web Site Documentview
The Little Dahlia that Could!ArticleMar '19ADS Bulletinview
Thrips ControlArticleMar '19ADS Bulletinview
Virus in Dahlia -
Be Part of the Solution
BrochureFeb '19ADSview


2018 Documentation

Virus in Dahlias -
Become part of the Solution
ArticleDec '18ADS Bulletinview
Greetings from the Dahlia Resource CenterArticleDec '18ADS Bulletinview
Virus Research Status UpdatePresentationSep '18ADS National Showview
Hide & Seek Virus TestingArticleJun '18ADS Bulletinview
Dahlia Testing - 2018 PlanArticleJun '18ADS Bulletinview
30-Year Battle Against Plant Viruses Leads
to Humboldt Award for Pappu
ArticleJun '18WSU Newsview
Summary of Virus Tests - 2017PresentationApr '18ADS Spring Meetingview
Viruses and Insects -
an Intricate Relationship
ArticleMar '18ADS Bulletinview
Virus Analysis in Dahlias - 2017ArticleMar '18ADS Bulletinview


2017 Documentation

Giant Boost for Dahlia R & DArticleDec '17ADS Bulletinview
Virus in DahliaArticleDec '17Dahlias of Todayview
Virus Research Update by Prof. Pappu - Part 1PresentationSep '17ADS National Show
Virus Research Update by Prof. Pappu - Part 2PresentationSep '17ADS National Show
A Visit to Washington State UniversityArticleSept '17ADS Bulletinview
Virus Success Story - 2016ArticleJun '17ADS Bulletinview
Virus Testing Plan for 2017ArticleJun '17ADS Bulletinview
WSU Virus Research - Project StatusPresentationApr '17ADS Spring Meetingview
Virus Analysis in Dahlias - 2016ArticleMar '17 ADS Bulletinview


2016 Documentation

Controlling Virus in Your Dahlia GardenArticleSept '16ADS Bulletinview
Virus in DahliaVideoSummer '16view
Now You Can test for Virus in Your GardenArticleJun '16ADS Bulletinview
Laboratory Testing for Virus in Our Dahlia GardensArticleMar '16ADS Bulletinview


2015 Documentation

Virus Testing Results for Fall 2015ArticleDec '15ADS Web Site Documentview
Virus Frequently Asked Questions (FAQs)PresentationSep '15Midwest Showview
Developing Virus Resistant DahliasArticleSep '15ADS Bulletinview
How Virus Effects Dahlia FoliageBrochureJun '15ADSview
ADS Interviews Dr. Hanu Pappu on the Appearance of Virus in DahliasArticleJun '15ADS Bulletinview