Christmas Cactus

Discussion in 'HortForum' started by Palm Nut, Jul 5, 2005.

  1. Palm Nut

    Palm Nut Active Member 10 Years

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    Vancouver BC Canada
    Just noticed my Christmas cactus has white powdery thingies on the joints of the leaves. Looks like some fungus. What should I do/use?
  2. HortLine

    HortLine Active Member 10 Years

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    Vancouver, BC
    There may be two problems associated with the white powdery substance on the leaves of your Christmas Cactus (Schlumbergera bridgesii):

    1. Powdery Mildew
    The first potential disease is powdery mildew (a fungus). This disease appears as a dusty white to grey coating over leaf surfaces (and is often mistaken for dust) and other plant parts. It is favoured by periods of high relative humidity and can be prevented by avoiding site conditions that foster such an environment (i.e., close spacing of plants, densely growing plants, or shade). We recommend you remove infected leaves or buds if possible and move the plant to a drier location with better ventilation.

    2. Mealy Bugs
    The second potential problem is mealy bugs. Mealy bugs lay their egg sacs in the leaf nodes (at the base of the leaf where it meets the stem); they appear as a white mass. The eggs will hatch 7 days later and spread over the plant secreting liquid and damaging the plant. Mealy bugs are small and white (like a fluffy grain of rice) and can spread to other plants nearby. The most effective way to curb damage by mealy bugs is to get them as soon as possible by handpicking them or by dabbing each bug with a cotton swab dipped in alcohol.

    If neither of these problems apply to your plant, feel free to write back with more information and we will try to help you further.



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