PESTTREE SPECIES AFFECTEDWHAT IS IT?PREVENTIONCONTROL
Aphidstulip tree, nannyberry, maples, alders, birches, dogwoods, basswoodTiny green to black, reddish brown, or dusty grey insects usually found in colonies which suck plant sap.do not over fertilize with nitrogenencourage native predators and parasites

spray plants frequently with a strong stream of water to knock aphids off

use mild soap spray or homemade garlic spray
Borers and Bark Beetlesmaples, cherries, pines, ashes, oaks, alders, basswoodLarvae of beetles bore into wood of trees. Attacked patches of bark exude gummy sap, turn dark and die. If bark dies entirely around trunk, the tree will die.avoid injury to barkremove injured limbs as soon as damage occurs
Webwormashes, pinesCaterpillars feed on leaves, eating holes until only a dry leaf skeleton remains.attract parasitic wasps with nectar or pollenknock caterpillars off leaves into pail of soapy water

remove host weeds in garden vicinityremove webs and destroy by burning or immersing in soapy water
Gypsy Mothbasswood, birch, oaks, serviceberry, pinesEuropean Gypsy Moth is a defoliating insect that can severely weaken or kill trees. It is a major introduced pest to North America.attract birds to your yard by planting appropriate plantsin spring, trap caterpillars by wrapping burlap around trunk of tree destroy caterpillars from this shelter every afternoon

scrape brown or yellow egg masses of trunks into bucket of soapy water
Leaf Minersbirches, oaksLarvae of these insects tunnel between leaf surfaces, feeding on leaf tissue.encourage native parasites with nectar plantsdestroy overwintering sites for insects by collecting and removing fallen leaves in Fall
Leaf Skeletonizershackberry, birches, oaks, cedar, basswoodInsects that specialize in eating the soft green tissue of leaves, but leave the network of veins. Often leave the top and bottom layers of leaf skin, giving leaves brown, papery appearance.maintain plant healthdestroy overwintering sites for insects by collecting and removing fallen leaves in Fall

insecticides are often ineffective as the pests are inside the leaves and do not have contact with sprays
Spider Mitesspruces, pines, cherries, basswoodMinute, 8-legged bugs which suck juice from cells on the undersides of leaves. attract parasitic wasps and woodpeckersplace a ground sheet under tree to catch larvae and destroy daily in soapy water
Scalesashes, hackberry, oaks, maples, redbud, alders, birches, dogwoodsSmall insects which suck plant sap, weakening the plants.attract native predators and parasites with nectar and pollen plantsprune and destroy infested wood

release predatory beetles
Tent Caterpillarsalders, birchesA native insect that rarely occurs in large enough numbers to cause tree death in Toronto. Populations peak every 10-12 years, then quickly return to tolerable levels.attract natural predatorsinsecticides are generally ineffective against mature larvae

caterpillars return to their tents during cool, wet weather and in evening prune and destroy nests during this time
Weevilspines, sprucesSmall beetles that feed at night consuming needles. Worst damage is from larvae feeding on roots and burrowing in crown of plants.avoid injury to treedestroy overwintering sites

drench soil around roots with parasitic nematodes
Adelgidspines, hemlockInsects that suck sap from undersides of limbs. They cover themselves with white powdery materialspray with soapy water solution

spray with dormant oil in late winter before growth begins
Carpenter Antsany tree with decayed woodLarge (8-11mm in length) black ants that live in colonies. They do not eat wood -their presence is usually an indicator of wood decay.Because carpenter ants only chew decayed wood, preventing wood decay is most important in preventing colonies of ants from colonizing a tree Monitor tree and have it assessed for safety by a certified arborist

do NOT seal or fill cavity
Fall Cankerwormoaks, ashes, maple, basswood, beech, birch, elm, hickoryInsect larvae, also known as loopers or inchworms, that feed on buds and new leaves in severe infestations causing heavy defoliation. May result in tree death if coupled with other stresses.Encourage parasitic wasps, virds, and ground beetles

Maintain plant vigour - healthy trees can releaf after being defoliated in early summer


Leaf RollerswillowsGreen caterpillars with brown heads that spin webs at branch tips, pulling leaves together and feeding on enclosed buds, leaves and developing fruit.encourage parasitic wasps such a Trichogrammaapply dormant oils sprays just before buds break in spring to kill egg masses

check branches of young trees weekly and remove caterpillars
Lace BugsaldersSmall insects with distinct lacelike pattern on wings and heads that suck plant juices on undersides of leaves, resulting in speckled white or grey blotched appearance on leaf surfaces.Spray with insecticidal soap


Sawfliespines, tamarack, spruces, ashes, birchesInsect larvae that look like hairless caterpillars that feed in groups and can quickly defoliate portions of a tree. There are many different species of sawflies, each prefers specific plantsmaintain plant healthhand pick larvae and drown in bucket of soapy water

monitor trees in spring for caterpillarsknock caterpillars off tree with strong water spray

spray with insecticidal soap
Spruce Budwormsspruces, balsam fir, tamarack, hemlockCaterpillars 1"" long, dark reddish-brown with white spots and black head that eat needles. Infestations can reduce tree growth and, if prolonged, lead to tree deathmaintain plant healthhand pick larvae and drown in bucket of soapy water

knock caterpillars off tree with strong water spray