| AFFECTING LEAVES: |
|
CONDITION |
CAUSE |
 |
Leaves
tied together with silk, chewed |
Oak leafroller (Archips
semiferana)
|
|
Black/brown
spotting on leaves |
Anthracnose (Apiognomonia
quercina)
|
|
Frothy
mass on leaf vein |
Spittlebugs (Clastoptera
spp.)
|
|
Insects
sucking on leaves |
Spider mites (Oligonychus
platani)
|
|
Small
balls on leaves |
Gall wasps (Cynipidae
spp.)
|
|
Cottony
growth on leaves, near midrib |
Gall wasps (Cynipidae
spp.)
|
|
Pale
green or yellow leaves |
Iron chlorosis
|
|
| AFFECTING TWIGS AND SMALLER BRANCHES: |
|
CONDITION |
CAUSE |
|
Twigs
shredded by multiple punctures |
Cicada oviposition injury (Platypedia
putnami)
|
|
Witches’
brooms on Gambel oak |
Oak witches’ broom (Articularia
quercina)
|
|
Areas of
dead bark with discoloration and small pimple-like fruiting bodies
(pycnidia) in the bark |
Cytospora canker (Valsa
spp., Leucostoma spp.)
|
|
| AFFECTING LARGER BRANCHES OR TRUNK: |
|
CONDITION |
CAUSE |
|
Clear to
white oozing or frothy malodorous liquid exiting from wounds |
Bacterial wetwood /
slime flux
|
|
Stem
decay and/or hoof-shaped fruiting bodies (conks) on Gambel oak |
White trunk rot of
oak (Phellinus everhartii)
|
|
| AFFECTING ACORNS: |
|
CONDITION |
CAUSE |
|
Grubs
feeding in acorn |
Acorn weevils (Carculio
spp.)
|
