Page 1 BwB FAQ’s 10/2019
Boxwood blight (blight) FAQs to address mechanics of enforcement/lessons learned:
1) If I have multiple licensed business locations and one is found positive for blight, can I still
move stock in and out of those other locations?
Locations within Maryland may move boxwood stock once thoroughly inspected and are considered
apparently free of blight. Locations in other states are under the rules and regulations of that other state.
2) How long does it usually take for MDA lab results to be provided to a nursery once plant
samples have been taken and then submitted for analysis in cases of blight?
This can vary anywhere from less than one week to 3 weeks depending on pathologist’s availability,
volume of samples being examined, and quality of samples (including the presence of fungicides, time of
year, etc.)
3) Are there any cases when MDA will sample and submit asymptomatic boxwood samples for
blight analysis? Generally not; except when highly susceptible cultivars are located in close proximity to
plants already deemed to be positive for blight. MDA may also take samples of declining stock, even if
not exhibiting typical blight symptoms, from a nursery recently confirmed to be positive.
4) If a nursery determines that they possess plants known to be positive for boxwood blight, is
that nursery required to contact MDA to report this? Nurseries under a Compliance Agreement are
required to report a positive blight determination to MDA. As a licensed nursery following state plant pest
control laws, this should also be reported so that MDA may notify the place of origin/shipping state (trace
back) and follow up with any customer (trace forward). MDA has contacts in other states who work with
their nurseries.
5) What is being done to try and keep blight out of Maryland? When does a pest move from
eradication/containment to management? MDA plant pest/pathogen policies are often set in response
to comply with another state’s regulations/quarantines. At the nursery level, we encourage the use of
BMPs and have developed agreements with some of our growers. Full eradication would require us to be
under a strict quarantine which would halt all interstate movement of boxwood stock; thus restricting MD
nurseries’ sales tremendously. This is not necessary or realistic. We manage blight by providing outreach
information about the disease and strongly encouraging the use of BMPs. MDA’s role is to make sure
that nurseries are compliant with plant pest control laws and do not knowingly sell infected/infested
nursery stock. With cooperation, we can both manage and seek eradication simultaneously if done
properly.
6) If I suspect boxwood blight in my nursery’s plant stock, can I destroy the affected plants right
away? Yes, MDA encourages proactive measures when dealing with potentially diseased plants. Notify
your nursery inspector regarding affected plants (symptoms, quantity, etc.), preserve a plant sample, and
be prepared to provide the source of the plants as well as any customers who have purchased these
plants so that MDA can follow up with them. Affected plants can be bagged and sent to a certified landfill,
burned (with a county burn permit), or by deep burial on site.
7) How do I know if a production grower is a “clean” nursery and provides plants that are free
from Boxwood Blight? As a state regulatory agency, MDA policy has no interest in identifying whether
nurseries, in Maryland or otherwise, have been found to be positive for plant pests/diseases. Regarding
Boxwood Blight, MDA encourages nurseries to seek licensed plant suppliers that are involved in some
form of Compliance Agreement or Clean Growing Program with their particular state’s agency. Though
Office of Plant Protection & Weed Management
50 Harry S Truman Parkway
Annapolis, Maryland 21401
www.mda.maryland.gov
Page 2 BwB FAQ’s 10/2019
the verbiage may vary by state, compliant growers should be able to provide certification that boxwoods
were grown under certain accepted conditions, have been “officially inspected”, and are therefore
“certified” to be disease free. Also, inquire about their production practices, their experience with
Boxwood Blight, their methods used to exclude plant diseases, and if/when fungicides are used.
8) Does MDA use a template for plant inspections? MDA Nursery Inspectors largely rely on visual
inspection techniques and many of the same references to blight symptoms that are utilized are available
on the MDA website, via MDA/USDA Pest Alerts, and the Pest Predictor Model. Educate nursery staff
and perform frequent inspections of your plant stock, especially when conditions favor the potential for
the outbreak of plant diseases like Boxwood Blight.
9) What is MDA’s stance regarding the use of sanitizers? If you are in a Compliance Agreement with
MDA, you must use sanitizers as outlined in that agreement pending any changes that may come from
improved research. Suggested sanitation practices are also described in Boxwood Blight BMPs.
10) Why, when upon a positive find for Boxwood Blight, are a nursery’s plants placed on Stop
Sale for an extended period of time (usually 90 days for further inspection), can an out of state
nursery suspected of sending infected plants continue to ship into MD without being placed
under a similar restriction? MDA is responsible for monitoring the health of plant stock at nurseries
within the state and, upon a positive find, for minimizing the risk of spreading pests and pathogens to
other sites. This is all to be done while not unnecessarily restricting plant sales. Without a restrictive
quarantine in place for Boxwood Blight, MDA’s role is to alert the appropriate agency of the state of origin
when blight is confirmed as their inspectors may have not identified symptoms prior to shipment or in
cases where the pathogen has been introduced during transport of the plant material into MD.
11) What is the process/timeline of events if Boxwood Blight is detected? The process varies due
to the type of nursery where Blight is detected (retail, wholesale, or grower). Once a positive find is
determined, a Stop Sale is issued for all boxwood plants on site and a Pest Control Order is created that
outlines the particular requirements thus determined. Depending on the situation, the nursery is often
given the choice for a full destruction of all boxwoods on site and subsequent sanitization of the nursery
or a partial plant destruction where asymptomatic boxwoods are removed from the sales area and
subject to a period of further inspection depending on the plants proximity to known positive plants, the
time of year, weather conditions, and any subsequent positive finds for Blight. In cases where a partial
destruction is agreed upon, no new boxwood plant stock may be brought into the nursery until this period
of inspection has been completed and the Stop Sale Order has been lifted.
12) How can a nursery minimize the impact of Boxwood Blight on their business? Key points to
minimize the potential impact of Boxwood Blight include: A) Keep incoming boxwood plant stock
separated from existing plants. B) Monitor all plant stock frequently and remove all declining/symptomatic
boxwoods. C) Utilize available Pest Alert information and tools such as the Pest Predictor Model:
https://uspest.org/risk/boxwood_app. D) Maintain complete records of all information related to
reputable, licensed plant suppliers, sales, use of herbicides and fungicides, and sanitation. E) Minimize
traffic/contact with nursery stock. It is ultimately up to the individual nursery to safeguard their facility and
their business reputation.
