| AFFECTING LEAVES: |
|
CONDITION
|
CAUSE
|
 |
Leaves
curled, chewed |
Boxelder leafroller (Archips
negundanus)
|
|
Leaves
thickened around midrib |
Gouty veingall midge (Continaria
negundinis)
|
|
New
growth is small, distorted |
Eriophyid mites
|
|
Sucking
on leaves, honeydew often present |
Boxelder and maple aphids (Periphyllus
spp.)
|
|
Small
cottony indentations on leaf underside |
Eriophyid mites
|
|
Masses
of reddish eggs on leaves |
Boxelder bug (Boisea
trivittata)
|
|
| AFFECTING LARGER BRANCHES OR TRUNK: |
|
CONDITION
|
CAUSE
|
|
Discolored
areas, dead bark containing small pimple-like fruiting bodies (pycnidia) |
Cytospora canker (Valsa
spp., Leucostoma spp.)
|
|
Open
wounds, internal decay, swollen areas in stem |
Stem decay fungi (Pholiota
sp., Pleurotus sp., and various fungal genera)
|
|
Fungal
fruiting bodies (mushrooms, conks) present |
Stem decay fungi (Pholiota
sp., Pleurotus sp., and various fungal genera)
|
|
| AFFECTING SEEDS: |
|
CONDITION
|
CAUSE
|
|
Feeding
on seeds |
Boxelder bug (Boisea
trivittata)
|
