| Disease |
Symptoms |
Pathogen/Cause |
Management |
| Basal Stem Rot |
At the soil line, a brown
spot forms. As the tissue dies, it becomes tan
and falls away, removing tissue from the edge to the heavy
center vein tissue. |
Fusarium oxysporum |
Do not injure plants at the soil line. Apply
iprodione or etridiazole + thiophanate methyl to protect healthy
plants. |
| Botrytis Blight |
Flowers die and become covered with gray fungal
growth. Under very high humidity conditions, stems may be attacked. |
Botrytis cinerea |
Heat and ventilate to maintain low relative humidity
in the greenhouse. Apply iprodione, fludioxonil, or mancozeb
for added protection. |
| Impatiens Necrotic Spot Virus |
Plants may be symptomless or may be yellowed,
spotted, or wilted. |
Impatiens necrotic spot virus |
Holiday cactus can be symptomless carriers of
this virus and serve as a source of this virus for other plants
in the greenhouse. Destroy plants with unusual symptoms. Maintain
strict thrips control throughout the year. |
| Phytophthora Root Rot |
Roots rot and plants turn gray-green, wilt, and
die. |
Phytophthora parasitica |
Plant in pasteurized potting mix. Discard infected
plants. Apply metalaxyl, etridiazole or etridiazole + thiophanate
methyl to protect healthy plants. |
| Pythium Root Rot |
Plants wilt and die. |
Pythium spp. |
Plant in pasteurized potting mix. Discard infected
plants. Apply metalaxyl, etridiazole or etridiazole + thiophanate
methyl to protect healthy plants. |
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