Tree Health Issues to Watch This Season
A Homeowner’ s Guide to Noticing Early Signs of Stress
Trees are remarkably resilient, but like people, they benefit from a watchful eye, good information, and care at the right time. Each season brings its own mix of weather patterns, insects, diseases, and environmental stressors that can affect the trees in our landscapes. The good news is that noticing changes early often gives homeowners more options.
Here are a few tree health concerns we are watching in Massachusetts this season.
Beech Leaf Disease
Beech Leaf Disease continues to be one of the most important tree health concerns in our region. It affects native and ornamental beech trees and is associated with a microscopic foliar nematode. Symptoms may include dark striping or banding between leaf veins, curled or leathery leaves, thinning canopies, and gradual decline.
Photo credit: Yonghao Li, The Connecticut Agricultural Experiment Station, Bugwood. org
Emerald Ash Borer
What to watch for: Dark bands between leaf veins, smaller leaves, thinning canopy, or leaves that look curled, leathery, or distorted. Best next step: Monitor beloved beech trees carefully and request an early professional evaluation if symptoms appear.
Emerald ash borer is now well established in Massachusetts. This small invasive beetle attacks ash trees from the inside, with larvae feeding beneath the bark and disrupting the tree’ s ability to move water and nutrients.
What to watch for: Canopy thinning, bark splitting, woodpecker activity, D-shaped exit holes, or shoots growing from the trunk or base.
Photo credit: Pennsylvania Department of Conservation and Natural Resources- Forestry, Bugwood. org
Best next step: If you have an ash tree you value, have it evaluated. If caught early enough, some high-value ash trees may still be candidates for treatment.
Spotted Lanternfly
Spotted lanternfly has continued expanding in Massachusetts communities. This invasive insect feeds on many woody plants and has a particular preference for tree-of-heaven, another invasive species often found along roadsides, disturbed areas, and property edges.
The insect is striking in its adult stage, with spotted wings and flashes of red. Younger nymphs are black with white spots and later develop red markings.
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Photo credit: Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood. org
What to watch for: Spotted adults, black-and-white or red-and-white nymphs, sticky honeydew, sooty mold, or activity around tree-of-heaven.
Best next step: Report suspected sightings and avoid moving materials that may spread egg masses.
Spongy Moth
Spongy moth, formerly known as gypsy moth, has been quiet in many areas recently, but it has not disappeared. Populations naturally rise and fall, influenced by weather, disease, predators, and winter egg mass survival. Oaks are a favorite host, though caterpillars can feed on many hardwood species. What to watch for: Egg masses on trunks, outdoor furniture, stone walls, or sheltered surfaces; caterpillars in spring; or unusual leaf feeding. Best next step: Observe first. If caterpillars or egg masses are present in large numbers, an arborist can help determine whether treatment is warranted.
Photo credit: Daniel Herms, The Ohio State University, Bugwood. org