Tree Pests/Tree Care

We offer a number of tree care options for pests (tent caterpillar, gypsy moth, emerald ash borer, bronze birch borer, etc), aesthetics (pruning, planting) or safety (removal). With a certified tree worker and ecologist on staff, we can assess the vegetation on your property and manage it for better drainage, aeration, or to reduce pest habitat. This is commonly the easiest way to reduce pests without ever using a drop of chemical!!

Seeing something strange on your trees? Snap some photos and send us an email, we can let you know what it is and what you can do to get rid of it.

Some common tree concerns with links to more information: 

Tent caterpillars

There are a few species of caterpillar that you may see on your trees. Proper identification is the first step towards effective pest control and luckily, it is fairly easy to tell the caterpillars apart. 

Treatment costs are highly variable depending on the situation, and may not be possible/merited. Below are photos to help you identify what is in your yard, and from there we can help you figure out if a treatment should be applied and advise approximate costs.  

The first thing to do is determine is whether or not there is a tent, or web. That, along with time of year, will allow you to figure out what you're dealing with. Caterpillars are cyclic, which means there will be a bad year here and there, then natural predators chime in to help get the population back under control. 

Tent caterpillar web in spring

Found in the spring in large numbers, eastern tent caterpillars form a web at a branch union, and expand the tent as they grow. There is a solid white line down the back, outlined by yellow lines. The caterpillars will congregate in the nest during the day, leaving at night to feed on foliage in the canopy.  

Webworm next in late summer

Tents formed at the ends of branches in late summer or early fall are fall webworm. This caterpillar stays within the tent through all instar stages, feeds within the tent, and only leaves to overwinter and pupate in the soil.  

Forest tent caterpillar

Forest tent caterpillars have 2 blue lateral stripes down the side of the body and white 'footprint' like markings down the center of the back. They do not form tents, contrary to the name's implication, and are commonly found on foliage or buildings through late spring and summer. 

gypsy moth

Gypsy moth caterpillars have 5 pairs of blue dots, followed by 6 pairs of red dots, down the back. They are hairy and do not form tents. In outbreak years when the cycle is heavy, these caterpillars can do extensive damage in one season. 

Emerald Ash Borer

Ash tree with extensive galleries excavated by the emerald ash borer grub

The emerald ash borer (EAB) is an invasive beetle that is decimating the ash trees of North America. It is the larval stage that does the damage. The grubs excavate galleries, as seen here, through the vascular area of the tree. This is where nutrients are transported up from the roots and down from the canopy, which is why the first signs of damage occur in the foliage.

Other signs of EAB presence are D-shaped holes in the trunk and woodpecker presence. The woodpeckers can sense the grubs under the bark and chip their way in to feed on them. This generally indicates a heavy infestation so the damage done by the beetle larvae is worse on the tree than the woodpecker feeding.

There is an injection treatment available for emerald ash borer, but we always caution its use. There are definitely scenarios where it works, but we don't want to mislead anyone. The cost varies with tree size but it is expensive. Research shows that it helps for 1-2 years on trees with less than 25% dieback, which is a pretty young infestation. If you have an ash on your property that means a lot to you, this might be a good option for you. The treatment will need to be repeated every other year until emerald ash borer is no longer a threat in the area. Alternatively, we're always happy to chat about replacement plantings utilizing other tree species.

Tar Spot


Tar spot is a fungus that infects mainly maple trees, mostly Norway Maple (​Acer platanoides​). The black spots that form on the foliage are usually smaller than the size of a loonie and don't tend to affect the overall health of the tree. The presence of tar spot points to excess moisture, so the canopy can be pruned strategically to increase air flow and create a drier environment.

The fungus overwinters on leaves at the base of the tree to re-infect the following spring. Raking and disposing of infected leaves in the autumn is a great way to reduce the presence of the fungus on that particular tree.

Maple leaf with black spots indicating a tar spot fungus

Sawyer Beetles

Pine sawyer beetle

Pine sawyer beetles are referred to by many different names, but are relatively easy to diagnose in a tree. These large beetles come from large larvae, which is the stage that does the damages the tree. The larvae (grubs) chomp away and create an audible 'crunch' as they infest the tree. When standing near the tree on a quiet evening this can be easily heard, even across the yard in our experience, giving away the infestation. The large adults then leave large, round exit holes when they emerge from the tree after pupating.

The adult beetles are also easy to identify with a white spot at the top of the wing union, as seen in this photo. They are grey with long antennae and a metallic shimmer. Sometimes the entire back will have small white spots, sometimes it will be uniformly grey, but there will always be a white spot on the thorax.

These beetles affect pine and other coniferous tree species, and often infest a tree after it has already been weakened by age, environment or damage. Often the tree is not worth salvaging at this point but there are methods of removal for special circumstances.

Black Knot

Black knot is a fungal disease in North America that attacks plum, cherry, apricot and chokecherry trees.  The disease produces rough, black growths that encircle and kill the infested parts, and provides a habitat for insects.

Black knot

Help! I don't know what it is!

That's ok, snap some photos and email us, we'll help diagnose and advise solutions.