| SYMPTOMS |
POSSIBLE CAUSES |
CONTROLS AND COMMENTS |
| Plants wilt; flowers
may drop and leaves may
turn yellow |
Dry soil
Water
logged soil
Transplant shock
|
Supply water
Improve drainage
Do not transplant in heat of day; water regularly
after transplanting
|
| Plant wilts and dies |
Root, stem or
corm rot (fungal or bacterial
disease)
|
Plant in well
drained soil; destroy
affected plants; use registered pesticides as soil drench
|
| Seedlings wilt; stems
turn brown and soft and
may be constricted at the soil line |
Damping off
(fungal disease)
|
Plant in well
drained soil
Use registered fungicide as soil drench
|
| Plants fail to
flower; foliage looks healthy |
Wrong season
Cool weather
Insufficient light
Too much nitrogen
Immature plants
Undersized bulbs
|
Plants have
specific day length
requirements for flowering
Do not plant sun loving plants in shade
Do not overfertilize; nitrogen stimulates
foliage, not flower, production
Biennials and perennials often do not flower
the first year
|
| Too many small
flowers |
Plants not
disbudded
|
Some flowers,
e.g. chrysanthemum, need to
have some buds removed to produce large flowers
|
| Tall, "leggy" plant;
stem and foliage pale or
yellow |
Insufficient
light
|
Pay attention to
light requirements of
plants
|
| General yellowing of
leaves; yellowing lowing
may be interveinal; plant may be stunted; no wilting |
Nutrient
deficiency
Virus disease
|
Soil test
Submit sample for laboratory diagnosis
|
| Grayish-white powdery
growth on leaves |
Powdery mildew
(fungal disease)
|
Use registered
fungicide
|
| Pustules containing
orange, yellow, or brown
powdery substance on leaves |
Rust (fungal
disease)
|
Resistant
varieties if available; use
registered fungicide
|
| Brown, dead spots on
leaves |
Fungal,
bacterial, or leaf nematode disease
(any of several)
|
Submit sample
for laboratory diagnosis
|
| Brown, dead areas on
margins of leaves |
Scorch, due to
hot, dry weather
Salt injury
Chemical injury
|
Supply water
Do not plant near sidewalks or drives that were
deiced in winter
Not common in home gardens
|
| Flowers wilt or fail
to open; grayish mold
appears on flowers in moist weather |
Gray mold
(fungal disease)
|
Pick off and
destroy affected flowers; use
registered fungicide
|
| Yellow and green
mottle or mosaic pattern on
leaves |
Virus disease
(any of several)
|
Remove affected
plants; do not touch
healthy plants after diseased ones; control insects
|
| Tiny white flecks or
white interveinal areas on
leaves |
Ozone injury
Spider mites
|
Use registered
miticide
|
| Clusters of insects
on stems or undersides of
leaves; leaves may be curled or distorted |
Aphids
|
Use registered
insecticide
|
| Leaves chewed or
completely eaten |
Various insects
Slugs and Sowbugs
|
Submit insect
for laboratory identification
Use beer bait or commercial slug bait
|
| Light colored tunnels
or blotches in leaves |
Leafminers
|
Use registered
insecticide
|
| Leaves stippled with
tiny white spots |
Spider mites
|
Use registered
miticide
|
| Tiny white winged
insects on undersides of
leaves |
Whiteflies
|
Use yellow
sticky boards (smeared with
grease) to trap them or use registered insecticide
|
| White, cottony masses
on leaves or stems |
Mealybugs
|
Use registered
insecticide
|
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