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Thousand Cankers Disease

Thousand Cankers Disease (TCD) is a disease of walnut trees, primarily black walnut, Juglans nigra in Maryland. It is caused by the activity of the walnut twig beetle, Pityophthorus juglandis, and the fungus, Geosmithia morbida.

Effective May 1, The Maryland Department of Agriculture (MDA) has detected and subsequently quarantined all movement of walnut material and hardwood firewood out of 185 square miles, which includes all of Baltimore City and portions of southeastern Baltimore County. A portion of Cecil County has been under quarantine for TCD since 2015, which will remain in place.

Walnut twig beetles spread the disease by carrying the fungus into the tree when they tunnel into walnut bark. The fungus colonizes the inner bark tissue, causing cankers around the insect galleries. This effectively girdles the twigs resulting in branch dieback. If beetles attack the trunk in large numbers, trees can be killed from the formation of numerous trunk cankers.

Reporting Symptoms

Symptoms include yellowing and wilting foliage, as well as branch dieback. People who suspect they have seen TCD should contact their local County extension office, or MDA’s Plant Protection section by emailing ppwm.mda@maryland.gov or calling 410-841-5920.

Learn More

Use the following resources to learn more about the walnut twig beetle and TCD:

Spotted Lanternfly

The spotted lanternfly is a new, non-native invasive insect first found in 2014 outside of Reading, Pennsylvania (Berks County). It has quickly spread throughout eastern Pennsylvania and a single adult spotted lanternfly was found on an insect trap in northeast Cecil County on October 25, 2018. Currently, this insect has not been detected in Baltimore County.

The spotted lanternfly is a threat to Maryland’s agriculture, nursery and forestry industries as it feeds on 70 different types of trees, plants and crops, including ornamental trees and plants. If you believe you’ve encountered this insect or an egg mass, place them in a small container or zip lock bag and inform the MDA by calling 410-841-5920 or emailing DontBug.MD@maryland.gov.

Learn More

Use the following resources to learn more about this insect and what is being done to manage it:

Free Reforestation

We are interested in open areas of one acre or larger that are available for planting. These areas shouldn’t contain any trees or infrastructure—only grass. Visit the Phase II Watershed Implementation Plan: Reforestation Efforts page for information and submit a Reforestation Property Form to the Environmental Protection and Sustainability department to determine your eligibility.

Baltimore County Tree Canopy Goal

Baltimore County's goal is to achieve and maintain a 50 percent tree canopy Countywide and within the three drinking water reservoirs by the year 2025. Additionally, the County will strive to achieve and maintain a 40 percent tree coverage within more populated areas inside the Urban Rural Demarcation Line and for each of the Census Designated Places (CDPs). Tree canopy maps and data on land cover are available by request for 30 CDPs in Baltimore County. These may be useful for finding opportunities for planting trees and for an understanding of overall tree canopy in a community and other such uses.

 
Revised May 21, 2019         

 

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