Learn About Tree Pest and Disease Management
The key to protecting your trees against the damaging effects of diseases is determining the issues source. With our tree care solution, you can count on our certified staff to diagnose the problems affecting your tree. Here are some common tree diseases, pests, and insects:
Gypsy Moths (Lymantria dispar dispar )
These pests, which are most destructive in their larval stage or as caterpillars, strip away foliage from a wide variety of trees. Repeated defoliation stresses trees and can lead to mortality, especially in urban or drought-stricken areas. In addition, gypsy moths can weaken tree regeneration due to impacted seed production and soot sprouting.
Signs and symptoms of a gypsy moth include:
- Egg masses on tree trunks and outdoor objects
- Holes in leaves
- Defoliation of trees
Defoliation will result in the dieback of twigs and branches. It will also make affected trees vulnerable to disease and other pests as they spend their energy reserves to regrow leaves in mid-summer.
Hemlock Loopers ( Lambdina fiscellaria )
The damage caused by hemlock loopers is visible on conifers during epidemics in late July and early August. The trees turn a reddish color, which is very characteristic of hemlock looper outbreaks. Feeding larvae damage the needles, causing them to dry, turn red, and drop in the fall.
Hemlock looper outbreaks develop and subside very suddenly. Additionally, the wasteful feeding of this species and its rapid population growth make it a serious defoliator.
There are 4 to 5 larval stages, depending on the region of Canada. When mature, larvae look for a pupation site. During heavy infestations, trees are covered with silk strands produced by larvae as they descend the tree trunks in search of food or pupation sites.
The insect has only one generation a year and overwinters in the adult stage.
Aphids ( Aphidoidea )
These small, soft-bodied insects feed by sucking the nutrient-rich liquids from plants. Some feed on only one type of plant, while others colonize various plant groups. Although aphids can vary widely in color, their common names include greenfly and blackly.
Tar Spot ( Phytisma acerinum )
Tar spots, caused by a fungal pathogen Rhytisma acerinum, are a common condition of the leaves of maple trees. They start as small yellow spots on growing leaves and expand into large black botches as the summer weather progresses. The treatment for this condition is a deep root fertilizer as well as disposal of the leaves.
Hemlock Wooly Adelgid ( Adelges tsugae )
These are aphid-like insects that attack and kill hemlock trees. Symptoms are the following:
- White "woolly" sacs that resemble tiny cotton swab ends at the base of hemlock needles on young twigs; these are most obvious in the spring
- Premature bud and shoot dieback
- Premature needle loss
- Thinner, greyish-green crown (healthy crowns are a shiny, dark green color)
- Dieback of twigs and branches
- Discolored foliage
- Death within 4 to 15 years
Scab and Rust Diseases
Rust disease first appears as small, yellowish-orange to reddish-brown flecks on grass blades and develops into raised pustules on blades and stems. Pustules are oval or elongated and contain powdery masses of yellowish-orange to reddish-brown spores. As the pustules mature, they turn from brown to black, and the heavily infected turf becomes thin and yellowish-orange to reddish-brown. Infected blades eventually turn yellow and die.