District of Columbia
8 active alerts in this region
TreeIssues monitors plant and tree health threats across District of Columbia. Below you will find current alerts for pests, diseases, fungi, and invasive species that have been detected in the state. Alerts are sourced from USDA, USFS, and District of Columbia state agricultural agencies. Each alert includes severity ratings, affected species, symptoms, and recommended treatments.
Dutch Elm Disease
CRITICALA devastating vascular wilt disease spread by elm bark beetles that has killed millions of American elms since the 1930s. The fungus blocks water-conducting vessels, causing rapid wilting. It fundamentally changed the American urban landscape.
Affecting 45 regions
Bacterial Leaf Scorch
HIGHA chronic bacterial disease that affects many shade tree species, particularly oaks, elms, sycamores, and maples. The bacterium is transmitted by xylem-feeding leafhoppers and spittlebugs and colonizes the water-conducting vessels, restricting water flow. Symptoms worsen each year as more of the canopy is affected. There is no cure.
Affecting 19 regions
Emerald Ash Borer
MODERATEAn invasive wood-boring beetle native to Asia that has killed hundreds of millions of ash trees across North America since its discovery in Michigan in 2002. Larvae feed on the inner bark, disrupting nutrient and water transport.
Affecting 36 regions
Spongy Moth (formerly Gypsy Moth)
MODERATEAn invasive moth introduced to Massachusetts in 1869. Caterpillars defoliate hundreds of tree species, preferring oaks. Repeated defoliation weakens and can kill trees, especially when combined with drought stress.
Affecting 20 regions
Japanese Beetle
MODERATEAn invasive beetle introduced to New Jersey in 1916. Adults skeletonize leaves of over 300 plant species while larvae (grubs) damage turf grass roots. They are particularly damaging to linden, birch, and fruit trees.
Affecting 35 regions
Anthracnose
MODERATEA group of fungal diseases causing leaf spots, cankers, and shoot blight on many shade trees. Sycamore, dogwood, maple, and oak are commonly affected. Cool, wet spring weather promotes infection of newly expanding leaves.
Affecting 38 regions
Powdery Mildew
LOWA widespread group of fungal diseases that produce a distinctive white powdery coating on leaves and shoots. It affects hundreds of tree, shrub, and plant species. Unlike most fungi, it thrives in warm, dry conditions with high humidity.
Affecting 49 regions
Leaf Spot Diseases
LOWA broad group of fungal diseases that cause discrete spots on the leaves of deciduous trees. Most are primarily cosmetic and do not seriously harm established trees. They are most common during wet spring and summer weather. Many different fungi cause leaf spots on different tree species.
Affecting 38 regions