Pest Name
American plum borer (moth)
Anthracnose of shade trees *
Apple blotch leafminer (moth)
Arborvitae leafminers (moth) *
Arborvitae weevil
Asian longhorned beetle
Azalea bark scale (felt scale) *
Azalea gall
Azalea leafminer (moth) *
Azalea whitefly
Bagworm (moth) *
Balsam gall midge
Balsam twig aphid *
Beech scale (bark crevice scale)
Birch leafminer (sawfly) *
Birch skeletonizer (leaf-feeding caterpillar)
Black knot *
Black spot *
Black turpentine beetle *
Black vine weevil *
Blight
Blight of junipers *
Blight of pachysandra *
Boxelder bug
Boxwood leafminers (fly larva) *
Boxwood mite
Boxwood psyllid *
Broad mite
Bronze birch borer (beetle) *
Brown marmorated stink bug
Brown rot
Calico scale (soft scale) *
Canker *
Cankerworms (moths) *
Cherry and hawthorn leafminer (sawfly) -- see hawthorn leafminer
Cherry scallop shell moth
Clover mite
Cooley spruce gall adelgid *
Cotton aphid/Melon aphid
Cottony maple scales *
Cottony taxus scale (soft scale) *
Crown canker *
Crown gall
Cryptomeria scale
Diplodia blight of pines *
Dogwood anthracnose *
Dogwood borer (moth) *
Dogwood sawfly
Douglas-fir needle midge
Downy mildew
Dutch elm disease
Eastern filbert blight
Eastern spruce gall adelgid *
Eastern tent caterpillar (moth) *
Elm bark beetles *
Elm casebearer (moth)
Elm leaf aphid
Elm leaf beetle *
Elm leafminer (sawfly)
Elm yellows
Elongate hemlock scale (armored scale) *
Emerald ash borer
Eriophyid mites, various species
Euonymous caterpillar *
Euonymus scale (armored scale) *
European elm scale (felt scale)
European fruit lecanium (soft scale) *
European hornet (wasp)
European pine sawfly (see pine sawfly for more information)
European pine shoot moth *
European red mite *
Fall webworm (moth) *
Fire blight *
Fletcher scale (soft scale) *
Forest tent caterpillar (moth) *
Fruittree leafroller (moth)
Golden oak scale (pit scale) *
Green peach aphid *
Greenstriped mapleworm (moth) *
Gypsy moth *
Hackberry psylla
Hawthorn leafminer (sawfly) -- also called cherry and hawthorn leafminer *
Hemlock looper (moth) *
Hemlock rust mite (eriophyid mite) *
Hemlock scale (armored scale) *
Hemlock woolly adelgid *
Hickory leaf stem gall phylloxera
Holly leafminers (fly) *
Honeylocust plant bug *
Honeylocust podgall midge (fly) *
Honeylocust spider mite
Honeysuckle aphid
Imported willow leaf beetle *
Inkberry leafminer (see Holly Leafminers)
Japanese beetle *
Japanese maple scale
Juniper scale (armored scale) *
Juniper webworm (moth) *
Kermes oak scales *
Lace bugs *
Larch casebearer (moth)
Larch sawfly
Leaf blister
Leaf curl
Leaf spot
Leaf spot on oak *
Leafhoppers, several species *
Lesser peachtree borer (moth) *
Lilac borer (moth)
Lilac leafminer (moth)
Linden looper (moth)
Locust borer (beetle)
Locust leafminer (beetle)
Magnolia scale (soft scale)
Maple bladder gall mite (eriophyid mite)
Maple mealybug
Maple trumpet skeletonizer (moth)
Mimosa webworm
Mountain ash sawfly *
Nantucket pine tip moth *
Needle blight
Needle cast
Needle cast on Douglas fir *
Needle rust
Northern pine weevil
Oak blotch leafminers (moths)
Oak leaf or twig galls, many species
Oak leaftier (moth)
Oak skeletonizer (moth)
Oak spider mite
Oak wilt *
Orangestriped oakworm
Oriental beetle
Oystershell scale (armored scale) *
Pales weevil
Peachtree borer (moth) *
Pear slug (sawfly)
Pear thrips
Pearleaf blister mite (eriophyid mite)
Periodical cicada
Pine bark adelgid *
Pine needle scale (armored scale) *
Pine needleminer (moth)
Pine root collar weevil
Pine sawflies *
Pine shoot beetle *
Pine spittlebugs
Pine tortoise scale (soft scale)
Pine tube moth
Pine webspinning sawflies
Pine webworm (moth)
Pitch twig moth
Polydrusus weevil
Poplar-and-willow borer (weevil)
Powdery mildew *
Privet rust mite (eriophyid mite)
Privet thrips
Redbanded leafroller (moth)
Rhododendron borer (moth) *
Rhododendron gall midge (fly)
Rhododendron stem borer (beetle)
Root rot
Rose chafer (beetle)
Roseslugs (sawflies)
Roundheaded apple tree borer (beetle)
Rust *
Rust mites, eriophyid mites, several species *
San Jose scale (armored scale) *
Sassafras weevil (magnolia or yellow poplar weevil)
Satin moth (leaf feeding caterpillar, tussock moth)
Scab of apple and pear *
Scarlet oak sawfly
Shoestring rot
Shoot blight
Sirex woodwasp
Slugs and snails
Snowball aphid *
Southern red mite *
Spruce bud scale (soft scale)
Spruce budworm (moth)
Spruce needleminers (moths)
Spruce spider mite *
Stem canker
Sugar maple borer (beetle)
Swiss needlecast *
Tar spots *
Taxus bud mite (eriophyid mite)
Taxus mealybug *
Tuliptree aphid *
Tuliptree scale (soft scale)
Tupelo leafminer
Tussock moths (moths)
Twig blight
Twig pruners (beetles)
Twobanded Japanese weevil *
Twospotted spider mite *
Viburnum leaf beetle *
Walnut blister mite (eriophyid mite)
Walnut caterpillar (moth)
White pine aphid *
White pine weevil *
White prunicola scale (armored scale) *
Willow flea weevil
Willow twig aphids
Winter moth
Witches broom
Woolly beech aphids *
Woolly elm aphid
Woolly larch adelgid
Zimmerman pine moth
Sign or Symptom:
"Cat facing" distortion on fruit
Adventitious growth
Aphids clustered on smooth bark of twigs and small branches
Bark fragments and frass collect on external bark along with gum
Bark removed from root crown
Black fecal spots
Blister-like scars on petioles
Blistering
Branch, shoot, or twig dieback
Broken twigs up to 3/4-in. diameter.
Bronzed foliage
Brown flowers
Brown foliage
Brown fruit
Brown spots on foliage, fruit, shoots
Brown spots or bands on needles
Brown tubelike cases on underside of leaves
Brown, dead flower buds
Brownish-black "varnish" spots on undersides of leaves
Bud loss, damage or deformity
Burr-like growth develop above girdled whorls
Callus tissue on midvein
Cankers on branches, twigs
Cankers on buds
Chewed leaves
Chlorotic leaves
Cottony egg masses on twigs, leaves or needles
Cracked bark
Crawlers settle in twig crotches, bark crevices, leaf axils
Cream-colored blisters on needles
Crown dieback
Cupped foliage
D shaped holes in bark
Damaged flowers
Dark spots on bark
Dark spots on foliage
Dead branches beyond canker
Dead foliage
Dead or wilting leader, often with "shepherd's crook" shape
Defoliation
Delayed leafing out in spring
Dense, hairy, feltlike pad on undersurface of leaflets
Discolored bark
Discolored blooms
Discolored foliage
Discolored spots on twigs
Discolored, sunken areas of trunk
Distorted bark
Distorted foliage
Distorted growth
Distorted shoots
Erratic shoot growth
Failure to leaf out
Feeds on leaf underside
Flaking bark
Flowing sap
Folded or rolled leaves
Foliage drop/dieback
Foliar damage usually not significant except in severe infestations
Frass
Gall at the base of new shoots
Gall-like insects in twig crotches
Galleries under bark
Galls
Galls on foliage or twigs
Girdled branches
Girdled trunks
Glistening slime trails
Gray crust on twigs or bark
Grayish foliage
Gummosis with frass at root crown
Holes in foliage or flowers
Holes in twigs, branches or trunk
Honeydew
Inchworms suspended from foliage
Knots on branches
Large scales encrusting twigs or young trunks
Lateral twigs most affected
Leaf curl
Leaf lesions
Leaf spot
Leaves tied together with silk
Light brown cups on fruit
Light green, pink, white, or brown galls on leaves, branches, flowers
Loss of bark
May kill young saplings
Mined foliage
Minor leaf damage
Necrotic areas on leaves and fruit
Necrotic stem tissue
Needles with slight swelling
Notched leaves
Only unfolding leaves are attacked
Ooze on flowers
Oozing sap
Orange or yellow spots on foliage
Orange stained bark
Partially consumed needles
Pitch accumulation
Pitch tubes on lower 6 feet of trunk
Plant appears scorched or ragged
Plant may appear drought-stressed
Plant mortality
Poodle appearance to plant
Presence of ants
Purplish red halos on young bark
Red frass collects on loose bark
Reddish brown foliage
Reddish brown twigs
Resin accumulation
Root rot
Roots consumed
Rough bark
Rust colored spots on fruit
Sap stain on bark
Sawdust
Scarred fruit
Scorched appearance
Second generation in late summer usually causes severe defoliation
Severe infestations can lead to leaf drop, dieback, or winterkill
Severely drooping branches (flagging)
Shepard's crook on shoots
Shredded leaves
Silk tubes
Silk webbing
Skeletonized foliage
Slits in bark of twigs
Small leaves
Small pineapple-shaped gall
Sooty mold
Sparse foliage
Spindle-shaped bags attached to twigs/foliage
Spittle masses on shoots
Stippled foliage
Stunted foliage growth
Stunted growth
Swelling at plant crown
Swelling bark
Swelling on branches, stems
Swollen areas on trunk
Terminals wilt and turn yellow
Thin crown
Tiny circular pits in buds and new shoots
Top-down death in 2-3 years
Twig dieback
Unthrifty plant
Watersprouts around trunk
Webbing on foliage
Webbing on twigs or branches
Wet spots on bark
White cocoons
White fuzzy patches on foliage
White ovisacs attached to underside of needles
White powder on new growth, fruit
White powdery patches on shoots
White spots on foliage
White woolly masses in crevices
Whitish, crystallized resin on wounds
Wilted foliage
Witches'-brooms on new shoots
Yellow foliage
Yellow, circular blisters on foliage