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Aphids & Tree Pests

Aphids on a leaf

Healthy trees are home to many different kinds of animals, including bugs. Unfortunately, many bugs can be annoying for people or could be harmful to the tree. These bugs are known as pests.

Pests on City trees

The City of Surrey manages pests on City-planted street trees using Integrated Pest Management Principles. By using this approach, Surrey:

  • uses an ecological approach,
  • decreases risk to people and the environment,
  • minimizes pesticide use,
  • considers community values, and
  • thinks about the long-term financial benefits.

If your City-planted street tree has any of the pests featured in the photo gallery below, call 604-501-5050 to have an arborist come look at the tree.

Common Pests in your Neighbourhood

Pests aren't limited to Surrey's street trees. They can be found anywhere in your neighbourhood, including your yard.


Aphids are the most common pest in Surrey. Aphids are tiny green bugs that sit on the undersides of the leaves, eating the sap. Their waste is known as “honeydew,” and you might notice it in the summer as a sticky film on your car or on the sidewalk.

Honeydew is not harmful to people or property, and the aphids won't cause any health problems for the tree. In fact, aphids are an important part of Surrey’s ecosystem. They provide food for other animals and beneficial insects like ladybugs.

Tips for dealing with aphids

  • Spray the underside of the leaves with your garden hose. The force of the water will knock the aphids out of the tree. Do this once per week to see results.
  • Park away from the tree. Aphid season is short, so if you are able to park somewhere else for the summer, and hose down your sidewalk, you’ll be able to ignore them.
  • Do not apply pesticides to your City-planted street tree. If the problem persists or seems extreme, call us at 604-501-5050 to have an arborist assess the tree. 


Cankerworms are small caterpillars, often called inchworms, that feed on the leaves of a variety of broadleaf trees in the late spring. As the feeding continues, only the leaf's larger veins and midribs will remain. Major outbreaks of cankerworms can defoliate entire trees.

Tent Caterpillars

Newly hatched tent caterpillars build a large tent out of silk in the joint of a deciduous tree (a tree that loses its leaves in the fall). They remain in this tent, emerging only to feed. Large outbreaks of this caterpillar can destroy entire trees or shrubs.

Leaf Skeletonizer

Leaf skeletonizer caterpillars feed on the lower surface of oak leaves leaving only the veins and giving the leaf a lace-like appearance. Larvae and pupae in white cocoons in heavily infested trees may become a nuisance in buildings, cars and other objects in and around your home.


Heavy infestations of scale insects can cause tree leaves to turn yellow to light green and may cause stunted growth of the leaves. The insects will appear on the under side of leaves around cottony masses.

Wasps and Hornets

Many species of wasps and hornets will build a round, paper-like nest in trees. Nests that are visible and near human activity can be a problem. If there is a concern about stings, the nest should be removed. Nests are active between June and September. Bees are important pollinators and should not be harmed.