Virus Testing 2024

With the cooperation of Professor Hanu Pappu at Washington State University (WSU) and the continuing support of the Scheetz-Chuey Foundation, the Dahlia Resource Center will focus on better understanding the nature and the behavior of the DNA viruses this year.


WSU Lab continues with excellence.
Picture left (2017), left to right: Brad Freeman, Cristian Olaya, PhD student, Dr. Ron Miner, Dr. Lindani Moyo, Dr. K. Madhu, and Dr. Ying Zhai.
Picture right (2022): Current members of Prof. Pappu’s lab at WSU (those working on dahlia viruses are in bold).
From left: Dr. Kasi Kotapati, Asad Ullah, visiting Ph.D. student, Richard Manasseh, PhD student, Dr. G. Prabu, Kristen Hamel, and Dr. Ying Zhai.


The Virus Team, working in conjunction with WSU, has concluded that the virus control strategies developed over the past several years are sufficient to let you maintain your dahlia gardens with a minimum amount of the RNA viruses we’ve been tracking: TSV, TSWV, INSV, and CMV.  Those strategies are 1) If in Doubt, Throw it Out; 2) Clean Between; and 3) Start with Clean Stock.  Those basics have been discussed in detail in previous articles in the Bulletin over the last 10 years.  See the 40+ articles in the “Virus Documentation Index” on this website for more specifics.

The Clean Stock Offense involving Club Testing and Vendor Testing has provided much of the basis for the development of the strategies cited.  They have also provided the opportunity to identify stock free of the RNA viruses.  In the last two years, they have also showed the very widespread presence of DMV/DCMV, a DNA virus.  The DNA viruses are so widely present, that the tests provide very little clean stock.  We are, therefore, suspending those routine tests for both the vendors and the clubs.  Please be aware that virus tests are commercially available, including home tests for the RNA viruses.  See Agdia, Inc. in Elkhart, IN, for example.

The Virus Team will continue to identify and gather stock clean both of RNA and DNA viruses and study the behavior of the DNA viruses in our gardens.  We will work to determine if we need other or more intense strategies to control the DNA viruses.  

We will also be running experiments to try to determine the best times to test dahlia plants for DMV to get accurate results. One focus will be how early in the season / stage of maturity the plants can be tested with minimal false negatives. Another will be to test individual plants through the season, especially those which test DMV+ early, to see if their DMV status changes in that time. We will also look for correlations between symptom expression and DMV status.


Subsidized Tests

The subsidized testing for Clubs and Vendors has been suspended for 2024 because the overwhelming predominance of DMV across the country has spoiled our ability to identify clean stock.  We hope that the research and testing we do this summer will lead the way to better ways to control DMV and any other DNA viruses.  That might lead to reinstatement of subsidized testing.