Christmas Cactus Diseases
Gary W. Moorman, Professor of Plant Pathology
| 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 cinierea | Heat and ventilate to maintain low relative humidity in the greenhouse. Apply fludioxonil, iprodione 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. |
Fusarium basal rot.
Active Ingredients and Trade Names of the Chemicals
| FRAC Group No. | Risk Level | Class | Active ingredient | REI Restricted Entry Interval | Trade names (EPA Reg. No.) |
|---|---|---|---|---|---|
| 1 | 3 | Benzimidazole | thiophanate methyl | 12 | 3336 (1001-69), OHP 6672 (51036-329-59807), Fungo Flo (51036-329-59807), Systec 1998 (48234-12) |
| 2 | 3 | Dicarboximide | iprodione | 12 | Chipco 26GT (100-1138), Chipco 26019 (264-481), Iprodione (51036-361), Sextant (51036-361-59807) |
| 4 | 3 | Acylanine | mefenoxam | 0 | Subdue MAXX (100-796) |
| 12 | 2 | Phenylpyrol | fludioxonil | 12 | Medallion (100-769) |
| U | 1 | Phosphonate | fosetyl-A1 | 12 | Aliette (432-890) |
DISCLAIMER
Notice: The user of this information assumes all risks for personal injury or property damage.
Warning! Pesticides are poisonous. Read and follow all directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams or ponds.
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