| AFFECTING LEAVES: |
|
CONDITION
|
CAUSE
|
 |
Large
holes chewed in leaves |
Redhumped
caterpillar (Schizura concinna) , or Forest
tent caterpillar (Malacosma disstria )
.
|
|
Silken
tents produced |
Western
tent caterpillar or Fall
webworm (Hyphantria cunea)
|
|
Caterpillar
living within a case |
Snailcase bagworm (Apterona
helix )
|
|
Terminal
leaves curled and tied together with silk |
Fruittree leafroller or
Obliquebanded leafroller
|
|
Skeletonized
leaves |
Apple and
thorn skeletonizer (Choreutis pariana) or Apple flea beetle (Phyllotreta
spp.)
|
|
"Shothole"
feeding wounds in leaf, usually with sucker growth |
Apple flea beetle (Phyllotreta
spp.)
|
|
Raised
leafmines |
Western tentiform leafminer
|
|
White
powdery material on upper or lower surface of leaf |
Powdery mildew
|
|
Pale
green or yellow leaves |
Iron chlorosis
|
|
Rust
orange spots |
Juniper rusts
|
|
Black
mold on surface of leaf |
Apple scab (Venturia
inaequalis)
|
|
Rusty
blisters or scabby patches on leaves |
Blister mites. See Eriophyid mites.
|
|
Bronzing
of leaves |
Two-spotted spidermite or
McDaniel spider mite
|
|
Curling
distortions of new growth in spring |
Rosy apple aphid
|
|
Blackened
and wilted leaves |
Fireblight (Erwinia
amylovora)
|
|
| AFFECTING TWIGS AND SMALLER BRANCHES: |
|
CONDITION
|
CAUSE
|
|
Twigs
shredded by a line of multiple punctures |
Cicada oviposition wounds
|
|
Blackened,
wilting, and crooked tips |
Fireblight (Erwinia
amylovora)
|
|
Black
beetle tunneling, with small exit holes |
Shothole borer
|
|
Scales
on twigs |
Oystershell scale or European
fruit lecnium
|
|
Cottony
insects on twigs |
Woolly apple aphid or Mealbugs
|
|
Discolored
areas, dead bark containing small pimple-like fruiting bodies (pycnidia) |
Cytospora canker (Valsa
spp., Leucostoma spp.)
|
|
| AFFECTING LARGER BRANCHES OR TRUNK: |
|
CONDITION
|
CAUSE
|
|
Boring
into trunk |
Flatheaded appletree
borer (Chrysobothris mali)
|
|
Bark
beetle tunneling, small exit holes |
Shothole borer
|
|
Cottony
insects on trunk and/or roots |
Woolly apple aphid
|
|
Internal
decay and/or shelf-like fruiting structures (conks) |
Decay fungus
|
|
Wilting
and dieback of portions of tree, originating from roots |
Verticillium wilt (Verticillium
spp.)
|
|
| AFFECTING GROUND LINE AREA OF TRUNK: |
|
CONDITION
|
CAUSE
|
|
Discolored
tissue under bark at ground line |
Phytophthora
root rot (Phytophthora spp.)
|
|
Galls at
ground line |
Crown gall
|
|
| AFFECTING ROOTS: |
|
CONDITION
|
CAUSE
|
|
White
root decay and white mycelial fans between bark and wood |
Armillaria root
disease (Armillaria spp.)
|
|
| AFFECTING FRUIT: |
|
CONDITION
|
CAUSE
|
|
Tunneling
in fruit |
Codling moth (Cydia
pomonella)
|
|
Scarring
or scabbing of fruit |
Fruittree
leafroller, Hail injury, or Apple scab (Venturia
inaequalis)
|
