| AFFECTING LEAVES: |
|
CONDITION
|
CAUSE
|
 |
Edge of
leaves cut in semicircle |
Leafcutter bees (Megachile
spp.)
|
|
Edge of
leaves notched |
Black vine weevil (Otiorhynchus
sulcatus)
|
|
Leaves
with blotchy mines |
Lilac leafminer (Caloptilia
syringella)
|
|
Leaves
blacken and wilted |
Bacterial blight (Pseudomonas
syringae pv. syringae)
|
|
White
powdery material on upper or lower surface of leaf |
Powdery mildew (Microsphaera
penicillata)
|
|
Leaves
turn a rusty color |
Rust Mites (eriophyid)
|
|
| AFFECTING TWIGS AND SMALLER BRANCHES: |
|
CONDITION
|
CAUSE
|
|
Scales |
Oystershell scale (Lepidosaphes
ulmi)
|
|
Borers |
Lilac/ash borer (Podosesia
syringae)
|
