| Disease |
Symptoms |
Pathogen/Cause |
Management |
| Alternaria Leaf Spot |
Small purplish spots
form on leaves. Their centers become brown
while the leaf yellows. |
Alternaria
dianthicola or Alternaria
dianthi |
Apply chlorothalonil, iprodione, mancozeb,
copper hydroxide, triflumizole, fludioxonil, or mancozeb +
thiophanate methyl to protect healthy plants. |
| Bacterial Slow Wilt or Stunt |
Wilting, twisting, curling, and stunting of
lower leaves and side shoots followed by death of lower leaves.
Wilted plants may recover only to wilt again. Stunted plants
have narrow, yellow-green leaves. Symptoms require several
weeks to develop. |
Erwinia chrysanthemi |
Grow in raised beds pasteurized between crops.
Use culture indexed cuttings free of the pathogen. Destroy
infected plants. |
| Bacterial Wilt |
Leaves turn gray-green then yellow and die.
Roots rot. Vascular tissue browns. Cracks develop in internode
tissue. Slime oozes from these cracks when humidity is high. |
Pseudomonas caryophylli |
Pot and propagate in pasteurized raised beds.
Use clean, disinfested tools. Use culture-indexed cuttings
free of the pathogen. Destroy infected plants. |
| Botrytis Blight |
Petals turn brown and are covered with gray,
fungal growth. |
Botrytis cinerea |
Space plants to ensure good air circulation.
Maintain low humidity. Avoid watering late in the day. Remove
crop debris. Apply copper, chlorothalonil, fludioxonil, iprodione,
or mancozeb + thiophanate methyl. |
| Fusarium Wilt |
Lower leaves yellow and wilt up one side of
plant. Symptoms progress up plant. Top the of main shoot grows
at right angle
to main stem. Late in the disease, roots and stems rot. |
Fusarium oxysporum |
Pot and propagate in pasteurized raised benches.
Use culture indexed plants free of the pathogen. |
| Fusarium Stem Rot |
Reddish-brown
spots at the base. No vascular discoloration occurs beyond
the rotted area. |
Fusarium graminearum,
F. aveneaceum, or F.
culmorum |
Plant only healthy, pathogen-free cuttings
in pasteurized, raised beds. |
| Greasy Blotch |
Small, web-like patterns give leaves a greasy
appearance. Leaves yellow and die. |
Zygophiala jamaicensis |
Maintain relative humidity below 85%. |
| Phialophora Wilt |
Plants wilt, leaves yellow, and vascular tissue
is discolored dark brown. |
Phialophora cinerescens |
See Fusarium wilt above. |
| Rhizoctonia Stem Rot |
Stems at the soil level have a lesion with
a brown border. Stems have dry, shredded appearance. |
Rhizoctonia solani |
Plant in pasteurized raised beds. Apply chloroneb,
fludioxonil, iprodione, thiophanate methyl + etridiazole,
or PCNB as a soil drench to protect healthy plants. |
| Rust |
Small blisters containing rust-red
spores form on leaves. |
Uromyces caryophyllinus |
Apply chlorothalonil, mancozeb + thiophanate
methyl, triadimefon, ziram, myclobutanil, or triforine to
protect healthy plants. |
| Viruses |
Leaves may be mottled, have yellow spotting,
dead flecks, line or ring spot patterns. Plant may be distorted
or have flower color breaking. |
15 different viruses are known. |
Plant virus-indexed cuttings. Maintain good
insect and mite control. Destroy infected plants. |
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