Affecting Trees & Shrubs

Aphids
Aphid
Description:
Pear-shaped, soft bodied insects; can we winged or wingless. Most commonly green but can be black, dark brown, yellow, white, bronze, red or pink.

 

Damage:
Suck sap while feeding on leaves, stems or roots. Can be found on growing tips, undersides of leaves, along stems and in roots.

 

Signs
Reduction in plant vigour; wilting and distortion of plant tissue - curled, puckered or distorted growth. Excrete honeydew, a sticky fluid that can lead to sooty mold development and also attracts ants, wasps and other flies. In some cases can cause red blistering on leaves.

 

What it attacks
All herbaceous and woody ornamentals

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Ash Leaf Cone Roller
Description:
Larvae small green caterpillar; adult is a small grey moth.

 

Damage:
Caterpillar role up in leaf and feed on leaf tissue.

 

Signs
Leaves rolled into a triangle cone, MINOR damage, aesthetic problem.

 

What it attacks
Ash

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Blister Beetles
Whitney Cranshaw, Colorado State University, Bugwood.org
Description:
Long, slender beetles that are brightly coloured with a metallic sheen.

 

Damage:
Adults chew rounded holes into leaves and flowers. Blister beetles produces a chemical called cantharidin which can cause blistering on the skin.

 

Signs
Defoliation of plants, reduction in plant vigour.

 

What it attacks
Annuals and perennials

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Blister Mites
Blister Mites
Description:
Very small, long slender white mite.

 

Damage:
Feed on leaves and fruit. As the mites feed blisters form on the surface of developing leaves. A small opening at the centre of the blister allows mites to move into and out of the blister. Blisters start out pale green, become increasingly pale until they turn yellow, then turn brown as the blisters expand and the affected tissue dies.

 

Signs
Cause buds to dry or fail to develop in the spring. Leaves are deformed and disfigured. Decreased plant vigour.

 

What it attacks
Mountain Ash, Cotoneaster, Pear and Apples

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Box Elder Bugs
Box Elder Bugs
Description:
Dull black insect with red marking outlining wings and thorax.

 

Damage:
Piercing, sucking insect that suck nutrients from seeds, foliage and young stems. Damage to trees is minor.

 

Signs
Negligible damage but often seen in large numbers on warm fences and walls which can be a little unnerving.

 

What it attacks
Manitoba Maple

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Caterpillar
Caterpillar
Description:
Elongated, worm-like insect with a segmented body, comes in a variety of colours, striping, speckling. Types of caterpillars loopers, cankerworms, leafrollers, hornworms, inchworms, fall webworm, larvae of moths and butterflies.

 

Damage:
Chew irregular holes in foliage of plants.

 

Signs
Severe cases may cause defoliation. Decrease in plant vigour.

 

What it attacks
All ornamentals, vegetables, fruit.

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Cottony Ash Psyllid
Cottony Ash Psyllid
Description:
Small insects that resemble cicada.

 

Damage:
Pierce leaf tissue and suck the plant juices, inject a toxin into the leaves as they feed. Feeding causes curling and distortion of leaves.

 

Signs
Tightly curled, distorted leaves - when you unroll leaves will find white cottony material surrounding the insects. Premature leaf drop and dieback. Decreased plant vigour.

 

What it attacks
Ash

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Elm Scale
Whitney Cranshaw, Colorado State University, Bugwood.org
Description:
Oval, grey-brown insects with a white waxy fringe; crawlers are yellow.

 

Damage:
Elm scales feed by piercing plant tissue, leaves and bark, and use plant juices.

 

Signs
Stunted, yellow foliage; premature leaf drop and dieback of branches. Excrete honeydew, a sticky fluid that coats the leaves and stems; sooty mold grows on the honeydew which interfere with photosynthesis and turns the branches and trunk of the tree black.

 

What it attacks
Elm

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Flea Beetle
Russ Ottens, University of Georgia, Bugwood.org
Description:
Very small, shiny black beetle with jumping hind legs.

 

Damage:
Young larvae feed on leaves causing skeletonizing; adults chew holes in the leaves.

 

Signs
Unsightly, nuisance.

 

What it attacks
Poplar, willow and other ornamentals.

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Forest Tent Caterpillar
Forest Tent Caterpillar
Description:
Large blue-black caterpillar are marked with white spots along the back.

 

Damage:
Chew irregular holes in the foliage causing defoliation of entire plants.

 

Signs
Cause a reduction in growth, die back, defoliation and in severe cases death of stressed plants.

 

What it attacks
Poplar, apples and other ornamentals

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Gall Insects and Mites
Whitney Cranshaw, Colorado State University, Bugwood.org
Description:
Small insects

 

Damage:
Feeding from insects causes distorted growth cause tissue to swell and form galls (bumps, woody growths, felty growth, smooth rounded growths) on leaves, petioles and stems.

 

Signs
Reduced vigour and aesthetic appeal.

 

What it attacks:
All herbaceous and woody ornamentals

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Leaf Beetles
Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org
Description:
Range of sizes, oval to elongated oval in shape, can be brightly coloured, have banding or striping.

 

Damage:
Chew holes in leaves or skeletonize leaves.

 

Signs
Found in clusters on the undersides of leaves, cause decrease in plant vigour.

 

What it attacks:
All ornamentals

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Leaf Cutter Bee
Joseph Berger, Bugwood.org
Description:
Small to medium sized bee

 

Damage:
Uses pieces of leaves to line egg cells in the hive.

 

Signs
Perfect round to oblong shaped holes appear on leaves. Cosmetic pest; Leaf cutter bees are valuable pollinators.

 

What it attacks:
Rose, lilac, ash, Virginia creeper

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Leaf Miner
Leaf Miner
Description:
Flattened caterpillars or maggots are the larvae of flies, moths, beetles and sawflies tunnel between the upper and lower leaf surfaces, feeding on soft tissue.

 

Damage:
Pale tan trails, blotches or bulges.

 

Signs
Close inspection of the leaf will reveal the insect inside the leaf or some fecal matter from the larvae. Can reduce plant vigour and cause stress.

 

What it attacks:
Common on Lilacs and Birch but can be found on many ornamentals

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Leaf Roller
Lacy L. Hyche, Auburn University, Bugwood.org
Description:
Green caterpillar with a brown head.

 

Damage:
Chews irregular holes in leaves, chews on blues, flowers and fruit rolls itself up in the leaf - essentially making a shelter to feed and grow.

 

Signs
Cause decline in vigour, distortion of growth and fruit.

 

What it attacks:
Woody ornamentals

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Leafhoppers
Leafhoppers
Description:
Small, slender pale green, yellow or white insects that jump and hop.

 

Damage:
Suck sap while feeding on leaves; disrupt sap flow of plants.

 

Signs
Bleaching and mottling of leaves; leaves may turn brown and curl up at the edges, plants become stunted with a decline in vigour.

 

What it attacks:
Virginia Creepers, Engelman Ivy, roses, woody ornamentals, perennials, and annuals.

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Oystershell Scale
Oystershell Scale
Description:
Light and dark brown, elongated oyster shaped insects.

 

Damage:
Attach themselves to branches and trunks, pierce the stems of the plants and feed on plant juices.

 

Signs
Stunted growth, yellowing and browning of leaves, dieback of branches, decreased vigour, weakening and death of plants. When scales cover stems it may look like rough bark.

 

What it attacks:
Cotoneaster, aspen, ash, lilac, dogwood, maple and other ornamentals

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Pear Slug
Pear Slug
Description:
Small olive-green to black, slimy, slug-like larvae.

 

Damage:
Feed on upper and lower surfaces of the leaves, skeletonize leaves.

 

Signs
Leaves are chewed between the veins, leaving a lacy translucent layer of tissue that turns brown.

 

What it attacks:
Pear, Rose and other plants in the Rose family, Oak

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Sawflies
Herbert A. 'Joe' Pase III, Texas Forest Service, Bugwood.org
Description:
Resemble caterpillar but have at least six pairs of legs; usually light green with a dark head.

 

Damage:
Chew irregular holes in leaves causing skeletonizing and defoliation. Feed from edge of the leaf in.

 

Signs
Cause defoliation and decrease in plant vigour.

 

What it attacks:
Most woody ornamentals

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Slugs
Slugs
Description:
Slimy black-brown speckled mollusks chew large irregular holes in leaves and gouging holes in ripe and unripe fruit.

 

Damage:
Irregular holes with smooth edges are chewed in leaves.

 

Signs
Slimy and/or shiny trails left behind by slugs.

 

What it attacks:
Ornamentals and fruit

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Spider mites
Spider mites
Description:
Tiny rounded eight-legged insect.

 

Damage:
Puncture leaf and suck out both water and food producing green chlorophyll.

 

Signs
Leaves become speckled with yellow blotches; stippling and dotting on leaves; leaves may fall prematurely; fine webbing on leaves, in leaf crotches or on flower buds; reduces vigour.

 

What it attacks:
All ornamentals

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Spittlebug
Spittlebug
Description:
Nymphs are pale green insects found in spittle mass, adults are small tan-brown insects that resemble leafhoppers.

 

Damage:
Suck sap from leaves, shoots and stems. Spittlebugs produce a spittle mass which is the combination of leaf juices, air and mucus; the spittle mass is to protect the insect from predators and from drying out.

 

Signs
Will see a spittle mass on stems on plants. Looks like someone spit on the plant. Nuisance, can be sprayed off with water.

 

What it attacks:
All ornamentals

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Thrips
Pennsylvania Department of Conservation and Natural Resources - Forestry Archive, Bugwood.org
Description:
Tiny, slender pale yellow, green or brown insects.

 

Damage:
Pierce plant cells and suck out the contents.

 

Signs
Injured tissue dies producing dead spots, distorted blooms and leaves, and balled flowers.

 

What it attacks:
Most ornamentals

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Western Ash Bark Beetle
James Solomon, USDA Forest Service, Bugwood.org
Description:
Small brown-black beetles; white legless grubs.

 

Damage:
Chew tunnels in the cambium layer (layer of actively dividing cells) just under the bark causing a disruption in nutrient flow; branches and trunk may be girdled.

 

Signs
Flagging, die back of branches, death of tree.

 

What it attacks:
Ash

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Wood Borers
Wood Borers
Description:
White legless larvae turn into beetles and moths.

 

Damage:
Larvae bore into the sapwood of the tree disrupting the nutrient and water flow of the tree. holes in the bark, sawdust in holes or at the base of the tree, wilting and death of branches or the whole plant.

 

Signs
Branches may fall over.

 

What it attacks:
Willow, poplar, aspen, birch, elm, ash and many more.