Boxwood Blight Update
February 27th, 2015
It has been a while since we last posted an update on Boxwood Blight. Having 3 snowfalls of nearly 20 inches in 9 days has allowed me to have a bit of time to write. I have talked with many of you at trade shows, on the phone, by email, in visits, and have updated you, but I wanted to briefly summarize to everyone what we know at this point.
The blight continues to show up in spots up and down the East Coast. However, it is not by any means as rampant and widespread as some had predicted. I believe at this point it has been found in nearly every state from Georgia to Massachusetts. Some of the cases have been clearly traced back to sources but unfortunately some cases remain a mystery as to how the disease was introduced. When the conditions were hot and dry we heard little, when it became favorable (high moisture, low airflow, warm temperatures) the disease showed itself. We believe one future means of managing the disease will be creating predictor models much like we use in the orchard for predicting fire blight outbreaks. When the weather conditions become conducive, extra measures will be taken.
Since the initial outbreak in the US in the fall of 2011, we have taken 4 trips to Europe to better understand the disease. In February of 2014, I had the opportunity to travel to Germany to the Essen Trade Show. It is the equivalent to the MANTS show for Europe and parts of Asia. It was an incredible learning opportunity to see what is happening there. I was able to talk to people who have been dealing with Box Blight for 20 or more years. I came away with three great takeaways.
Speaking of varieties, this past July, we were able to see firsthand some of the varietal susceptibility testing that was concluded in the summer of 2014 at NC State. Some varieties we already grow, such as Green Beauty, Jim Stauffer, Insularis ‘Nana’, and Winter Gem are very tolerant of the disease while ‘Suffruticosa’ (English) was devastated by the disease in a side by side trial. We are firm believers this battle will be won on the variety front. A few rules of thumb we observed:
• Sempervirens cultivars are the most susceptible.
• Microphylla and insularis cultivars are most tolerant.
• Plant architecture plays a big role. Dwarf microphylla are more susceptible due to lesser air flow and sempervirens that are more open or have better air flow are more tolerant.
The battle with Boxwood Blight is only beginning. We, both those in the wholesale market as well as those in the retail market, must continue to educate our customers and adopt best management practices which will minimize its damage and slow its spread.
Until our next update, Happy Gardening and please wish for some spring-like weather!
The latest update on the boxwood blight from Saunders Brothers, Inc.
Best Management Practices - Feb. 24, 2012
A New Disease for Connecticut and the USA 12-08-2011
Symptoms CT 12-08-2011