| Disease |
Symptoms |
Pathogen/Cause |
Management |
| Botrytis Blight |
Flowers have small,
translucent, or dead spots. |
Botrytis cinerea |
Maintain low relative humidity. Apply fludioxonil,
chlorothalonil, fenhexamid, mancozeb, or a mixture of the two
to protect plants. |
| Phytophthora Crown Rot |
Branches wilt and the plant rapidly dies as the
crown. Young plants are quickly killed. Outdoors if the weather
is dry, the stem at the soil line may have a dry rot. |
Phytophthora parasitica |
Use pasteurized potting mix or soilless mix known
to be free of pathogens. Discards flats containing infected
plants. Apply fosetyl-Al, etridiazole, etridiazole + thiophanate
methyl, metalaxyl, mefenoxam, chlorothalonil, or propamocarb
to protect remaining plants. |
| Powdery Mildew |
White, mealy fungal growth develops on leaves.
Leaves yellow and die. |
Oidium |
Apply myclobutanil or kresoxim methyl to protect
plants. |
| Stunt |
Young plants are stunted and thick. |
Lack of boron |
Maintain a soil pH below 7. Have a water test
done to be certain calcium and sodium are not too high. |
| Virus |
Small etches on the leaf are surrounded by a
dark halo. |
Impatiens necrotic spot virus (INSV) |
Destroy infected plants. Take steps to control
western flower thrips. Examine other plants in the greenhouse
for INSV symptoms and destroy them. |
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