Dahlia Tuber Disease

Before disposing of your tuber stock be sure to get them tested to see if there is disease. There is one lab in the United States that tests for leafy gall, Oregon State University. Melodie Putnam, leading scientist studying gall has recently retired, however the lab can still isolate the bacteria. Other university labs can test for crown gall pathogens. 

Leafy gall is also known as Rhodococcus fascians, and crown gall is also known as Agrobacterium. 

  The Lowdown on Leafy Gall  by Melodie Putnam 

Keep in mind... 

  • Tubers can be showing multiple shoots and still test negative. For bacteria to be cultured it must be showing visible signs of the disease. 

  • When we are digging tubers from the field we dispose of any tubers that are showing signs of disease to avoid storing them with other tubers.

  • Although there is a growing awareness about tuber disease in the industry, information about the effects on plant habit is still being determined.

Tuber Disease Protocol

If you believe there is an issue with your tuber or plant please use the link below to fill out a dahlia tuber support ticket.

Oregon State University Lab Results

Test Results on Dahlia Tubers with Suspected Visible Symptoms of Gall

Additional Resources

The Lowdown on Leafy Gall  by Melodie Putnam

Is it Crown Call or Leafy Gall?by Melodie Putnam and Marilyn Miller

Growing Dahlias- Iowa State Extension & Outreach

Dahlia Mosaic Virus on Dahlia- Utah State University