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Monday - July 01, 2013

From: Emory, TX
Region: Southwest
Topic: Diseases and Disorders, Herbs/Forbs
Title: Unknown ailment of Turk's cap in northeast Texas
Answered by: Guy Thompson

QUESTION:

I just moved from the Dallas area to Emory in the north east part. I brought two young Turk's cap plants in pots. I had to leave the mother plant behind. The tops have a very curled and shrunken appearance and one plant has this strange stuff on it that looks like sugar or salt granules. I can't see any pests but there has to be something there. The mother plant never had any problems. How can I treat this?

ANSWER:

One of the most common problems of Malvaviscus arboreus var. drummondii (Turk's cap or turkscap) in Texas is powdery mildew.  This fungus disease often shows up on leaves near the top of the plant, causing the leaves to be somewhat shriveled and spotted with areas of powdery white fungus.  The white areas are often more extensive on the lower side of Turk's cap leaves.  It is not too serious a disease, but the affected leaves should be removed and the plant sprayed with fungicide.  The Safer company makes a sulfur-containing, biodegradable, combination fungicide/insecticide that might be appropriate for the situation, although in my experience fungicides seem to slow down but not eliminate the disease completely.

Powdery mildew does look somewhat like POWDERED sugar but not granulated sugar or salt.  So we should consider that your problem may be of another sort.  If the white material looks something like cotton you may be having an infestation of mealy bugs.  These individual bugs have a cottony appearance, and you can find some easy control methods in this eHow site How to Control Mealybugs.  The Safer product mentioned above should be effective for mealy bugs as well as any other insect pest.

If your problem is powdery mildew, it can spread by spores wafted through the air and settling on leaves in a moist or humid setting.  It would be good if you can position your Turk's cap plants where they can get some early morning sun or good air circulation to dry off dew or humid air as quickly as possible each day.  This would lessen the chances for continued serious outbreaks of the disease.

 

From the Image Gallery


Turk's cap
Malvaviscus arboreus var. drummondii

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