Tree Health in Massachusetts

An 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.

Asian Longhorned Beetle

A large wood-boring beetle that attacks hardwoods including maples, elms, willows, and birches. Native to China and Korea, it was first detected in New York in 1996. Infestations can kill trees within a few years.

Spotted Lanternfly

An invasive planthopper native to China first detected in Pennsylvania in 2014. While it primarily threatens agriculture (grapes, hops, fruit trees), it feeds on over 70 plant species. It excretes honeydew that promotes sooty mold growth.

Hemlock Woolly Adelgid

A tiny aphid-like insect native to Asia that feeds on hemlock sap at the base of needles. It has devastated eastern hemlock populations from Georgia to Maine. Trees typically die within 4-10 years of infestation.

Spongy Moth (formerly Gypsy Moth)

An 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.

Japanese Beetle

An 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.

Bagworm

A moth whose larvae construct distinctive spindle-shaped bags from silk and foliage fragments. They feed on over 100 species of trees and shrubs, with conifers being most vulnerable since they cannot regrow lost foliage as readily.

Dutch Elm Disease

A 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.

Fire Blight

A bacterial disease that primarily affects members of the rose family, including apple and pear trees. It can destroy entire orchards in a single season. Bacteria spread rapidly during warm, wet spring weather through blossoms and wounds.

Cedar-Apple Rust

A fungal disease requiring two hosts to complete its life cycle: eastern red cedar (juniper) and apple or crabapple trees. It causes economic losses in apple orchards and aesthetic damage to landscape cedars.

Anthracnose

A 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.

Powdery Mildew

A 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.

Apple Scab

The most economically important disease of apples worldwide. The fungus overwinters in fallen leaf litter and releases spores during spring rains. Severe infections reduce fruit quality and yield and can defoliate trees by mid-summer.

Chestnut Blight

A fungal disease that functionally eliminated the American chestnut as a canopy tree species in eastern forests by the mid-20th century. Once numbering in the billions, mature American chestnuts are now exceedingly rare. Root sprouts survive but are re-infected.

Beech Leaf Disease

An emerging disease caused by a foliar nematode first identified in Ohio in 2012. It has spread rapidly through the native range of American beech. Affected trees can decline and die within 6-10 years. No effective treatment exists at scale.

Armillaria Root Rot

One of the most widespread and destructive forest diseases in the world, caused by a complex of honey mushroom species. It attacks stressed trees through root contact and can persist in dead stumps for decades, infecting nearby healthy trees.

Diplodia Tip Blight

A common fungal disease of pines, particularly Austrian and Scots pines in landscape settings. Spores infect new shoots as buds open in spring. Repeated infections progressively kill branches from the bottom of the tree upward.

Rhizosphaera Needlecast

A common fungal disease of spruce trees, especially Colorado blue spruce, throughout the Midwest and Northeast. The fungus infects current-year needles through stomata, causing them to turn purple-brown and drop prematurely. Inner and lower branches are affected first because humidity is higher there, and the disease progresses upward and outward over successive years. Severely affected trees may retain only the current year's needles at branch tips.

Stigmina/SNEED Needlecast

A fungal disease of spruce very similar in appearance to Rhizosphaera needlecast but caused by a different fungus. Often occurs alongside Rhizosphaera. It has become increasingly recognized as a major cause of spruce needle loss, particularly on Colorado blue spruce. Diagnosis requires microscopic examination to distinguish from Rhizosphaera.

Pine Wilt Disease