Panelists talk of boxwood blight during conference

Staff Writer

Linthicum, Md. (March 14, 2016) —A panel of three regulators and one grower addressed boxwood blight at Chesapeake Green on Feb. 23.
Dana Rhodes, state plant regulatory official for the Pennsylvania Department of Agriculture, said Pennsylvania is the only state with a quarantine in place, although other states are considering one.
Two positive finds in Pennsylvania in 2012 were in stock that had been shipped in. By 2015, of 150 locations sampled, there were more than 100 positive finds.
“Big box stores were a big part of this,” Rhodes said. “If we find one positive in a single multi-location store, all the stores must stop selling boxwood.”
In order to ship boxwood into Pennsylvania now, growers must have an inspection by their state and produce a phytosanitary certificate.
If boxwood blight is found in a shipment, the state will require the producer to go into a systems approach. A second such find puts everything on hold and requires more sampling.
“After three strikes, you may no longer ship to Pennsylvania. We are protecting our historical gardens and landscapers,” Rhodes said.
PDA has developed a “Voluntary Boxwood Cleanliness” cooperative agreement with eight pages of steps participants agree to take to prevent the introduction and minimize the risk of spreading boxwood blight.
“We believe in the systems approach,” Rhodes said. “If I put the steps into law, you’d have to do them, whether they applied or not. The quarantine is for one year, so far. We are working together to make things better for everyone.”
Robert Trumble, from the office of nursery inspection at Maryland Department of Agriculture, said Pennsylvania’s quarantine had a silver lining by bringing more attention to the disease.
“Pennsylvania has set the bar very high,” he said. “They’re not messing around. There’s incredible detail involved to meet the Pennsylvania requirements. Maryland is taking this very seriously. We want to continue to be known as producers of boxwood blight-free boxwood.
Norm Dart, Virginia state plant pathologist, said there’s not a lot of difference between what Virginia has been doing for the last five years and what is current in Maryland and Virginia.
“We can’t order plants destroyed,” he said. “We can only stop sales.
“We don’t require homeowners to destroy plants (where blight is found), but we recommend it. Homeowners have the legal right to manage boxwood on their property the way they want to.
In a question-and-answer period that followed, Robert Saunders of Saunders Brothers in Virginia, noted he heard of one two-gallon boxwood being added to a 50-year-old planting which took out all the boxwood there within a week.
He tells vendors not to put any boxwood on the same truck with his orders. English boxwood was the No. 1 plant at his nursery, Saunders said earlier.
Saunders Brothers grows more than 20 varieties of boxwood, and English “is sliding down the list,” he added. Still 35 percent of Saunders Brothers’ income is boxwood-related.
Saunders has flown to England four times to research boxwood blight.
“We are ahead of the EU in developing new varieties,” he said. “Some are tolerant.”
Along with 1,000 varieties of others shrubs, trees and herbaceous plants, his nursery is testing nearly 100 varieties of boxwood.
North Carolina State University evaluated 23 varieties of boxwood and rated them according to susceptibility, Saunders said. “Sempervirens is highly susceptible. English boxwood is the No. 1 victim. Its days are done.”
A few showing tolerance are B. harlandii ‘Richard’, B. sinica var. insularis ‘Nana’, and B. sinica var. insularis ‘Franklin’s Gem’. B. microphylla ‘Little Missy’ in zone 5 is “tough as nails,” he said.
The staff at Saunders Brothers wear tyvex clothing and washable boots. There are cleaning stations between sections in the nursery where workers not only clean tools and go through a foot bath but also change pants.