North Carolina Plant Disease and Insect Clinic


Disease Problems:


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Monday - Friday

NC Plant Disease & Insect Clinic
3141 Ligon Street
Unit 4, Room 206
Raleigh, NC 27607
Directions to the Clinic

Department of
Plant Pathology

Department of



Plant Disease and Insect Clinic

News & Alerts


Posted by M.J. Munster on 19 Jun 2013

The emerald ash borer (EAB), a destructive exotic insect pest, has now been detected in North Carolina. These beetles feed under the bark of ash trees (Fraxinus spp.), eventually killing them. The detection is not unexpected, as EAB was already present in Virginia and Tennessee. In North Carolina, Person, Granville, and Vance Counties are under a quarantine. No movement of ash trees or ash wood products, or of hardwood firewood, is allowed from these counties. The reason is that EAB can be present inside these materials and inadvertently moved long distances by people.

For more, including contact information if you suspect you have found this pest, see the NCDA&CS Press Release 17-Jun-2013

Further information is found on the NC Forest Service EAB FAQ page.
Note: At the time of this writing, that FAQ page still had not been updated to reflect the fact that this is now in North Carolina.


Adult of the emerald ash borer next to cm ruler.

The adult of the emerald ash borer is about a half-inch long, and metallic green in color. Photo: Matt Bertone.

Thousand Cankers Disease Confirmed in North Carolina

Posted by M.J. Munster on 04 Jan 2013
last update: 04 Jan 2013

The North Carolina Department of Agriculture and Consumer Services put out a press release yesterday confirming the presence of thousand cankers disease in the North Carolina portion of the Great Smokey Mountains National Park, and implementing a quarantine on walnut trees and wood products from Haywood County, North Carolina. Areas of Tennessee, Virginia, Pennsylvania, and several western states were already known to be infested. This potentially devastating disease is caused by a beetle-borne fungus and affects only walnut trees (including butternut). It often goes by the shorter name "Thousand Cankers" or simply "TCD".

The North Carolina Forest Service has created an FAQ page with details about thousand cankers disease. Important: Symptoms will not be evident until the summer. If at that time you suspect TCD on your property, contact the NCFS at the phone number or the email address provided on their FAQ page. The public is asked not to take any samples themselves. We also remind you of the risks of moving wood and branches for firewood or for woodworking. Additional information on tree disesases and pests can be found at the NCFS Forest Health Notes.

Yellowing leaves and thinning crown of black walnut with thousand cankers

Thousand Cankers Disease symptoms on black walnut in Colorado.
Photo: Ned Tisserat, Colorado State University,

Happy New Year 2013 from the
NCSU Plant Disease and Insect Clinic

Posted by M.J. Munster on 02 Jan 2013
last update: 02 Jan 2013

The Plant Disease and Insect Clinic is open and operating during regular hours. For those who plan to come to the clinic in person, please note that Dan Allen Drive will be closed at the railroad trestle from 9am to 5pm daily, starting on January 14th. The main visitors' entrance will not be affected. See the north campus map for the route to the Clinic. Do not hesitate to call us if you have any questions. 919-515-3619.

For those still looking for a New Year's resolution, consider making good sampling a priority. This web site contains detailed instructions by crop type, from the "How to Submit a Sample" button at left. You can also go straight to our videos on sampling and packaging.


Downy Mildew of Impatiens Confirmed in North Carolina

Posted by M.J. Munster on 18 Jun 2012
last update: 18 Jun 2012

Downy mildew of impatiens was confirmed last week from multiple locations in North Carolina. This is the first time since 2007 that the Plant Disease and Insect Clinic has confirmed the presence of the pathogen (Plasmopara obducens) in our state. Producers, retailers, landscapers, and homeowners will want to check impatiens for signs of this fast-spreading and destructive disease. Symptoms include leaf yellowing and curling, and defoliation. A characteristic white felt of spores may form on the underside of infected leaves under favorable conditions. Fortunately, only impatiens are affected by this particular species of downy mildew. New Guinea impatiens are tolerant. More information is available on our blog, and in the June 15, 2012 edition of NC Pest News.

heavy sporulation of Plasmopara obducens on impatiens leaves

Downy mildew on impatiens (Photo: Kelly Ivors)


Box blight now present in NC and US

Posted by M.J. Munster on 29 Nov 2011
last update: 17 Jan 2012

The presence in North Carolina of box blight, caused by the fungus Cylindrocladium pseudonaviculatum, was confirmed in October 2011. This fungus has been present in Europe and New Zealand for several years, but has now made its first appearance in the USA. The only known natural hosts for this fungus are species of Buxus, and the infestation in North Carolina appears to be very limited in extent. For further details on the disease, the situation, and what to do if you suspect it in your boxwoods, see the Alert by Drs. Kelly Ivors and Anthony LeBude at See also the guide to box blight symptoms.

NCEES and NCDA&CS personnel, please see this additional information.

blighting of leaves and stems on a small containerized boxwood plant

Containerized boxwood with box blight


Expanded range for Laurel Wilt in NC

Updated 22 February 2012

The fungus that causes laurel wilt (Raffaelea lauricola) has been confirmed for the first time in Brunswick County.  NCFS Forest Health staff found symptomatic trees in Brunswick County near Sandy Creek.  Stained wood samples were sent to the USDA Forest Service Southern Research Station Laboratory in Athens, GA, where culturing confirmed the presence of the pathogen. 

Counties in North Carolina where laurel wilt is known to be present include Bladen, Brunswick, Columbus, Pender, and Sampson (map).

Red Bay Ambrosia Beetle Found in North Carolina

Article by Steve Bambara, April 15, 2011

Updated February 22, 2012

The red bay ambrosia beetle, Xyleborus glabratus, and the fungus Raffaelea lauricola, together
constitute an insect/disease threat. Currently, laurel wilt has been reported in five counties in North Carolina: Bladen, Brunswick, Columbus, Pender, and Sampson.

The beetle transmits the fungus which causes the disease known as laurel wilt. The combination is generally fatal to red bay, which is an important maritime forest species and is also sometimes found in the landscape. The decline of red bay may have secondary implications for some animals and other plant species

Other plants in the laurel family, including sassafras, are also susceptible to the fungus. This disease complex poses a serious threat to the avocado industry in Florida. More information about laurel wilt external link


Symptoms of laurel wilt. Images by James Johnson (Bugwood external link)

New Publication by Extension Plant Pathologists

Posted by M.J. Munster on 31 Aug 2011

We are pleased to announce the release of a new extension publication, AG-747 "Suggested Plant Species for Sites with a History of Phytophthora Root or Crown Rot". The brainchild of former PDIC Director Tom Creswell, this document provides replant recommendations for use when Phytophthora has been diagnosed in landscape ornamentals. Tables are presented for annual bedding plants, herbaceous perennials, and woody ornamentals (trees and shrubs). The compact URL for emailing is

Azalea with small leaves, leaf loss, and dieback due to Phytophthora root rot

Azalea showing symptoms of Phytophthora root rot. Image by Dr. Kelly Ivors

Cucubit downy mildew returns to North Carolina

Posted by M.J. Munster on 27 June 2011

On 16 June 2011, the Plant Disease and Insect Clinic confirmed the year's first North Carolina case of cucurbit downy mildew, caused by the fungus-like organism Pseudoperonospora cubensis. It came from a cucumber field in Sampson County. Shortly thereafter, the disease was reported in Hertford and Alamance counties. This disease is capable of infecting all cucurbits, including cucumber, cantalope, squash, pumpkin, and watermelon. For more information and commercial control recommendations, see the 24 June 2011 issue of North Carolina Pest News. For the current status of the disease and forecasts of areas at risk, see the Cucurbit Downy Mildew Forecast Homepage.

typical downy mildew symtpoms on cucumber: angular chlorotic then necrotic leaf spots

Symptoms of downy mildew on cucumber. Image by Mike Munster

Camellia petal blight

Posted by Barbara Shew, March 21, 2011

Petal blight is common on japonica camellias almost every year during bloom time in North Carolina. Wet weather and mild winter days favor this disease.


Petal blight symptoms. Note the
ring of white fungus in the base of the flower.

Petal blight is caused by the fungus Ciborinia camelliae. This fungus produces large, hard, black, irregular-shaped structures at the base of infected flowers. These structures survive on soil or mulch until the following winter, when they produce small mushroom-like bodies. These “mushrooms” produce thousands of tiny spores that infect camellia flowers, starting a new cycle of infection.  

Because the fungus structures produced in the flower are the source of future infections, the best way control this disease is to remove all fallen flowers and debris from around your camellias. The fungus structure is too large and hard to be completely destroyed by composting, so infested debris should be disposed of completely.