The following is basic information about identifying the pests that attack various plants in your yard and garden.
Vegetable Pests
Aphids
pear-shaped, soft bodied insects often found in colonies. Can be pale green, yellow, brown, black or pink.
- Injure plant by sucking sap causing leaf distortion and reduced growth; can transmit diseases
- Attack - all vegetables
Colorado Potato Beetle
rounded, hard shelled beetles, alternating black and yellow stripes; larvae are red humpback with two rows of black spots on each side
- Feed heavily on leaves and stems, small plants are most severely damaged
- Attack - eggplants, peppers, potatoes and tomatoes
Flea Beetles
small black or black and yellow beetles that jump like fleas eat pin-sized holes in the leaves destroying the leaves
- Attack - cabbage, beets, broccoli, Brussels sprouts, corn, eggplant, kohlrabi, potato, radish, rutabaga, tomato, turnip
Root Maggots
small, white, legless maggots
- Maggots tunnel into roots rendering them inedible. Plant appear stressed, leaves may turn yellow. In severe cases plants may wilt and die
- Attack - broccoli, Brussels sprouts, cabbage, cauliflower, radish, rutabaga, turnip and others
Cutworms
fleshy, caterpillar-like worms that curl up when disturbed.
- Sever stems at or just below ground level. Feed at night
- Attack - all vegetables
European Corn Borer
large green, brown or pink caterpillars with dark brown head found inside the stalks or within the ears
- Feeds on leaves, stalks and ears. Leaves are riddled with tiny shot holes; bores into stalks or ears to feed on the cob and kernels
- Attack - corn and tomatoes
Cabbageworm
velvety green caterpillar with a yellow stripe running down its back
- Chew ragged holes in the leaves; may bore into heads and contaminate edible portions
- Attack - broccoli, Brussels sprouts, cabbage, cauliflower, kale, radish, turnip
Leafhoppers
small pale green insects that jump and fly
- Damage plants by sucking the sap. Leaves may be stippled, curled, puckered or brittle. Carry and transmit viruses and diseases
- Attack - carrots, celery, cucumber, lettuce, potato
Thrips
tiny, slender, pale yellow, green or brown insects
- Feed by rasping plant tissue then sucking the released plant sap. The injured tissue dies, producing dead spots, distorted blooms and leaves and balled flowers.
- Attack - bean, cabbage, onion, pea and other crops
Evergreen Pests
Aphids
pear-shaped, soft bodies insects
- Suck sap while feeding on the branches and needles; causes a reduction in plant vigour; excrete sticky honeydew on which sooty / black molds grow
- Attack - all evergreens
Pine Needle Scale
tiny white, flattened scaly insects
- Suck sap from needles causing needles to develop a yellow mottling, turn brown then drop
- Attack - spruce, pine, fir, hemlock and cedar
Sawflies
small light green caterpillars with a black head or yellowish caterpillars with yellow-orange head
- Feed on needles - defoliating branches; causes stress which can make plants vulnerable to other pests and diseases
- Attack - spruce, larch, cedar, pine
Spruce Budworm
yellow caterpillar with a dark brown head are covered with white spots
- Feed on developing buds and needles; in severe cases all new growth will be consumed
- Attack - Spruce, fir
Spruce Gall Aphid
pear-shaped, white, wooly soft-bodied insects
- Cause the formation of galls at the tips of the branches - feed on new growth. Galls emerge green, turn purple then eventually brown. Galls cause tip kill and may distort or yellow needles
- Attack - Spruce, fir
Spider Mites
tiny, rounded, eight-legged insects
- Puncture foliage and suck plant sap; foliage becomes stippled yellow and looks dirty. A fine webbing may be present
- Attacks - all evergreens
White Pine Weevil
white, legless larvae with light brown heads; adult is a dark brown beetle with a prominent snout
- Feed under the bark of new leaders eventually girdling the stem. The leader wilts - looks like a shepherds crook
- Attacks - spruce, pine
Tree, Shrub, Rose, Perennial and Annual Pests
Aphids
pear-shaped, soft bodies insects
- Suck sap while feeding on leaves; causes a reduction in plant vigour, wilting and distortion of leaves and flowers; excrete sticky honeydew on which sooty / black molds grow. In some cases can cause red blistering on leaves.
- Attack - all herbaceous and woody ornamentals
Blister Beetles
long, slender, black, purple or metallic green beetles
- Chew rounded holes into leaves
- Attack - annuals and perennials
Blister Mites
tiny white mites
- Cause reddish, yellow or brown blisters on the leaves
- Attack - Mountain Ash, cotoneaster, pears, apples
Box Elder Bugs
brownish-black insects with red stripes on the wings
- Suck nutrients from the seeds, foliage and young stems. Damage to trees is minor
- Attack - Manitoba Maple
Caterpillars
common types loopers, cankerworms, larvae for moths and butterflies
- Chew irregular holes in foliage; severe cases may cause defoliation. Only in severe cases will the overall tree health be affected
- Attack - all ornamentals
Flee Beetles
very small, shiny black beetles that hop
- Chew holes or skeletonize leaves
- Attack - poplar, willow and other woody ornamentals
Forest Tent Caterpillar
large blue-black caterpillars are marked with white spots along the back
- Chew large, irregular holes in foliage causing defoliation of entire plants. Voracious feeders that can lead to reduced growth, die back and in really severe cases death of stressed plants
- Attack - poplar, apple and many other ornamentals
Gall Insects and Mites
small insects
- Cause formation of galls - felty bumps of the leaf surface, petiole or stems.
- Rarely cause serious damage - more aesthetic
- Attack - poplar, elm and other woody ornamentals
Leafhoppers
small, slender pale green, yellow or white insects that hop
- Sap-sucking insects that cause bleaching or mottling of leaves. Sometimes the leaves turn brown and curl up at the edges. Plants may become stunted with a decline in plant vigour
- Attack - Virginia Creeper, roses, annuals and perennials
Leaf Beetles
small brown or black and yellow insects
- Found in clusters on the undersides of leaves; chew holes in leaves or skeletonize them
- Attack - poplar, willow
Lilac Leaf Miner
small flattened yellowish caterpillar
- Mine between the leaf layers causing yellow or brown blotches; then exit, roll up the leaf from the tip and continue to feed causing skeletonizing of the upper leaf surface. More of an aesthetic problem.
- Attack - lilac
Leaf Roller
green caterpillar with a brown head
- Rolls itself up in the leaf to feed. Chews irregular holes in leaves, chews on buds, flowers and fruit
- Attack - most woody ornamentals
Pear Slug
small, olive-green to blackish, slimy, slug-like worm
- Feed on the upper and lower surfaces of the leaf. Leaves are chewed between the veins, leaving a lacy, translucent layer of tissue that turns brown
- Attack - Pear, Rose and other plant in the rose family
Rose Gall Wasps
wasplike insects
- Lay eggs in stems of roses causing large swellings or galls.
- Attack - Roses
Sawflies
resemble caterpillars but have at least six pairs of legs; usually green with dark head and black or black and yellow stripes
- Feed on leaves either skeletonizing leaves or feeding in from the edges
- Attack - most woody ornamentals
Slugs
slimy black-brown speckled mollusks
- Cause large irregular holes in leaves and gouging grooves in ripe and unripe fruit
- Attack - most ornamentals and fruit
Spider Mites
tiny, rounded, eight-legged insects
- Puncture foliage and suck plant sap; foliage becomes stippled yellow and looks dirty. A fine webbing may be present
- Attacks - all ornamentals
Thrips
tiny, slender, pale yellow, green or brown insects
- Feed by rasping plant tissue then sucking the released plant sap. The injured tissue dies, producing dead spots, distorted blooms and leaves and balled flowers.
- Attack - most ornamentals
Western Ash Bark Beetle
small brown-black beetles; white legless grubs
- Larvae chew tunnels in the cambium layer under the bark causing a disruption in nutrient flow; branches and trunks may be girdled and die
- Attacks - Green Ash
Wood Borers
white legless larvae mature into beetles or moths
- Larvae bore into the sapwood of the tree. External symptoms - holes in bark through which insects expel sawdust-like excrement, young branches may wilt death of branches or the whole tree.
- Attack - willow, poplar, birch, elm, ash and many more
Fruit Pests
Currant Fruit Flies
legless white larvae
- Develop within the fruit which turns red and drops prematurely
- Attack - currant, gooseberry, Saskatoon
Imported Currantworm
yellow and black sawflies
- Feed on foliage - can completely defoliate shrubs in the spring
- Attack - currant, gooseberry
Leaf Rollers
greenish-white caterpillars with a brown head
- Feed on fruit, buds and leaves. Leaf in rolled together and fastened with silk, larvae live and feed within the rolled leaf
- Attack - most fruit
Raspberry Fruitworm
tiny brown beetles
- Feed on emerging foliage, damaging foliage, buds and blooms. Wormlike larvae tunnel into flower buds and developing fruit. May cause reduce yields
- Attack - Raspberry