Boxwood Blight
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BOXWOOD BLIGHT
-Update on Boxwood Blight in Connecticut-
A brief update on the current status of boxwood blight in Connecticut by Dr. Sharon M. Douglas is now available. This reviews the status of boxwood blight on boxwood and pachysandra in the landscape as well as in production nurseries in Connecticut--no nurseries have tested positive for boxwood blight since they implemented Best Management Practices: Update on Boxwood Blight (467 kb, 2 pages, PDF format*).
--RECENTLY REVISED--
Guidelines for Reporting and Managing Boxwood Blight in Connecticut Landscapes Ver. 2.0
The Connecticut Agricultural Experiment Station (CAES) has full statutory authority for plant diseases, as stated in Sec. 22-84 and Sec 22-98 of the Connecticut General Statutes. Therefore, in Connecticut, regulatory actions for boxwood blight, caused by the fungus Cylindrocladium pseudonaviculatum (syn. Calonectria pseudonaviculata) are under the statutory authority of CAES. Official diagnosis must be confirmed by CAES plant pathologists. Samples from any symptomatic/suspicious boxwood and/or pachysandra plants should be sent to The Connecticut Agricultural Experiment Station (CAES) for testing and confirmation.
This newly revised document by Dr. Sharon M. Douglas is titled Guidelines for Reporting and Managing Boxwood Blight in Connecticut Landscapes Ver. 2.0 (197 kb, 7 pages, PDF format*, revised 12 October 2012). It specifies what to do when boxwood blight is found or suspected on boxwood or pachysandra in the landscape and also provides detailed information on how to remediate and manage the disease in landscape settings. These guidelines provide options for situations when boxwood, pachysandra, or both hosts are present on a property.
Boxwood Blight Confirmed on Pachysandra in a Connecticut Landscape
A natural infection of pachysandra in the landscape by Cylindrocladium pseudonaviculatum, the boxwood blight fungus, was confirmed by CAES plant pathologists on 29 June 2012. The pachysandra sample had been collected by a CAES inspector while visiting a residential property in Fairfield County that had installed B&B boxwood plants in May 2012. These plants had been confirmed by CAES to be infected with boxwood blight one week prior to the visit. The inspector noticed that an established bed of pachysandra bed adjacent to the infected boxwood had unusual, foliar symptoms, so he collected the sample to bring to the diagnostic lab for examination. This new report follows the previous report of pachysandra as an experimental host of boxwood blight by CAES (Plant Disease 2012, Vol. 96:1069).
Residential landscape with newly installed, infected boxwood adjacent to infected pachysandra
(P. W. Trenchard).
Numerous, small, necrotic lesions with yellow haloes (S. M. Douglas).
A report by Dr. Sharon M. Douglas titled Boxwood Blight Confirmed on Pachysandra in a Connecticut Landscape (340 kb, 2 pages, PDF*) is available.
Follow this link to a BOXWOOD BLIGHT OF PACHYSANDRA IMAGE GALLERY.
Best Management Practices (BMPs) for Boxwood Blight for Connecticut
-FOR LANDSCAPERS AND RESIDENTIAL, PUBLIC, AND COMMERCIAL PLANTINGS-
This new set of BMPs for boxwood blight is specficially written for landscapers and residential, public, and commercial boxwood plantings. It addresses what needs to be done to minimze the risk of introducing boxwood blight-infected plants into properties with established plantings of boxwood. It also includes guidelines for installing new plantings of boxwood. As with other BMPs released by The Connecticut Agricultural Experiment Station, these BMPs are working documents that are going to evolve as we learn new information about this disease. Please note that it has a version number, in anticipation of the release of new versions in the future. We encourage comments and suggestions. This new document by Dr. Sharon M. Douglas is titled Suggested Best Management Practices for Boxwood Blight for Connecticut-For Landscapers and Residential, Public, and Commercial Plantings (Version 1.0)(171 kb, 4 pages, PDF format*).
New Host: Pachysandra
Plant pathologists at The Connecticut Agricutural Experiment Station recently identified Pachysandra terminalis (common names: pachysandra, Japanese spurge) as a new host of Cylindrocladium pseudonaviculatum, the fungus that causes Boxwood Blight. Healthy pachysandra plants were inoculated with spores of C. pseudonaviculatum and lesions developed on the leaves ten days after inoculation. Three weeks after inoculation, many of the leaves with lesions yellowed and dropped. Heavy sporulation of the fungus was observed. This raises significant concerns about pachysandra as a potential source of inoculum for infection of boxwood and vice versa. More information will be forthcoming.
Pachysandra with leaf lesions (J. A. LaMondia).
Sporulation on lower leaf surface (J. A. LaMondia).
Disease New to Connecticut and the U.S.
In October 2011, a disease of boxwood new to Connecticut and the United States was identified by The Plant Disease Information Office. Samples of boxwood with unusual symptoms were submitted for diagnosis and after extensive microscopic examination and a search of the literature, the disease was tentatively identified as boxwood blight, caused by the fungus Cylindrocladium pseudonaviculatum. This identification was subsequently confirmed by national mycologists at the United States Department of Agriculture-Animal Plant Health Inspection Service-Plant Protection and Quarantine (USDA-APHIS-PPQ) in Beltsville, MD. To date, boxwood blight has also been found in North Carolina, Virginia, Maryland, Rhode Island, Massachusetts, Oregon, New York, Pennsylvania, and Ohio. It has also been found in two provinces in Canada (BC and ON). It not known how the pathogen was introduced into the U.S.
A new fact sheet by Dr. Sharon M. Douglas has color photos to help identify this new disease and also discusses strategies about how to minimize its impact. The fact sheet is titled Boxwood Blight--A New Disease for Connecticut and the U. S. (REVISED July 2012, 1,563 kb, 9 pages, PDF format*).
A "CAES Disease Alert" on Boxwood Blight by Dr. Sharon M. Douglas is also available. This short, two-page alert includes a brief description of the symptoms and several color photos (690 kb, 2 pages, PDF format*).
If you are concerned that your boxwood plants might have boxwood blight, information about how to send or bring samples to the Experiment Station for diagnosis can be found at: http://www.ct.gov/caes/cwp/view.asp?a=3756&q=442802&caesNav=|.
Best Management Practices (BMPs) for Boxwood Blight for Connecticut
Best Management Practices (BMPs) for boxwood blight for Connecticut, Connecticut Best Management Practices for Boxwood Blight--Positive Production Nurseries (125 kb, 5 pages, PDF* format) and Connecticut Best Management Practices for Boxwood Blight--Production Nurseries, Dealers, and Garden Centers (117 kb, 3 pages, PDF* format), and a letter on The Current Status of Boxwod Blight in Connecticut (430 kb, 1 page, PDF*format) from Dr. Louis A. Magnarelli, CAES Director, and Dr. Kirby C. Stafford, CAES Vice Director and State Entomologist, to National Plant Board Member States and the Nursery Industry have recently been released.
We consider these BMPs to be working documents that are going to evolve as we learn new information and receive input from the green industry professionals. These are suggestions for the industry, not regulations. Please note that they have version numbers, in anticipation of the release of new versions in the future. We encourage comments and suggestions.
Boxwood Blight Presentation from New England Grows 2012
Presentation by Dr. Sharon M. Douglas titled Boxwood Blight- A New Threat to Boxwood in the U.S. (7,481 kb, 127 pages, PDF format*). From New England Grows 2012, 3 February 2012 (Boston, MA).
14 November 2012 (updated)
Content Last Modified on 11/16/2012 9:19:35 AM
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