| AFFECTING LEAVES: |
|
CONDITION
|
CAUSE
|
 |
White
powdery material on upper or lower surface of leaf |
Powdery mildew (Sphaerotheca
pannosa)
|
|
Leaves
with white spotting |
Rose leafhopper (Edwardsiana
rosae) or Twospotted
spider mite (Tetranychus urticae Koch) or Rust (Phragmidium mucronatum)
|
|
Small
ball-like growths on leaves, usually reddish |
Gall wasps
|
|
Leaves
mottled with yellowish areas |
Iron chlorisis or
Rose mosaic complex (various viruses are responsible)
|
|
Orange-red
colored patches on lower leaf surface |
Rose rust
|
|
Angular
brown spots on leaves |
Anthracnose
|
|
Interior
areas of leaves chewed |
Roseslug and other
sawflies (Endelomyia aethiops)
|
|
Even,
semicircular cuts in leaf edge |
Leafcutter bees (Megachile
spp.)
|
|
Leaves
curled |
Powdery mildew or Aphids
|
|
Dark
spots on leaves |
Black spot (Diplocarpon
rosae)
|
|
| AFFECTING CANES: |
|
CONDITION
|
CAUSE
|
|
Insects
tunneling into pith of cane |
Leafcutter bees (Megachile
spp.)
|
|
Exterior
area of cane girdled, sometimes with associated dieback |
Bronze cane borer / Rose stem girdler (Agrilus
aurichalc)
|
|
Mossy or
ball-like growths on stem |
Gall wasps (Diplolepsis
sp.)
|
|
Woody,
tumor-like growth, usually on lower stem |
Crown gall (Agrobacterium
tumefaceins)
|
|
Swellings
in canes, often with associated vertical cracking |
Bronze cane borer / Rose stem girdler (Agrilus
aurichalceus)
|
|
Purple
to tan, sometimes sunken spots on canes |
Rose canker (Cryptosporella
or Leptosphaeria sp.)
|
|
| AFFECTING FLOWERS: |
|
CONDITION
|
CAUSE
|
|
Flower
buds killed, fail to emerge (“blind” shoots) |
Rose midge (Dasineura
rhodophaga); Fluctuating, cool temperatures; or
Rose
curculio (Merhynchites bicolor)
|
|
Flower
petals scarred |
Flower thrips (Thysanoptera
spp.)
|
|
Flower
petals chewed or tunneled |
Earwigs (Forficula
auricularia L.), Rose
curculio (Merhynchites bicolor)
|
|
Flowers
produced are “off-type” after winter (Grandiflora and hybrid tea roses) |
Die back to the
grafted rootstock
|
