Question
QUESTION: What can be done with a gardenia plant that appears to have white mold
growing on some branches and continues to lose leaves and have branches die.

ANSWER: Hi there.I am a tree man but I found an answer from one of the other volunteers that sounds like your problem.
If your description is accurate, then powdery mildew is the problem. (If the white stuff looks like tiny bits of cotton, then it is mealybug and will require a different treatment.)

Powdery mildew appears as irregularly shaped patches of white on the leaf and stem surfaces of some plants. This fungus wipes off leaves, but brownish leaf spots often are left behind. Powdery mildew often attacks tender new growth and destroys it. Once established on a plant, powdery mildew is hard to eradicate because the microscopic spores float invisibly through the air and onto other areas of the plant.

The first step in treating powdery mildew is the cut off the infected tissue, usually the entire leaf or stem. Next you can try spraying all leaf surfaces and stem surfaces and also the surface of the soil with a solution of 1 tsp. baking soda to a quart of water. The sulfur in garlic is also effective, so you can spray with a solution of garlic and water. Safer's makes a non-toxic sulfur spray for mildew. It is reasonably effective but will leave a strong sulfur odor on your hands, so use rubber gloves. Neem oil and horticultural oil sprays are also effective treatments for powdery mildew.  Repeat the spray treatments again in about a week.

NOTE: Be sure to test any of these sprays on a single leaf before spraying the entire plant to be sure that it does not damage the plant

Powdery mildew thrives in locations that are warm, humid and lacking good air circulation. Installing a fan nearby can help deter powdery mildew.
Hope this helps,Bill


---------- FOLLOW-UP ----------

QUESTION: Thanks for all of the info.  After reading your reply, i believe it probably is not
mold but is the mealybug.  How do I handle this?

Thanks so much Bill.  

Answer
Here's a little more info and safe method:

Transportation: People and pets may transport Mealy bug indoors. Mealy Bugs can crawl from an infected plant to a non-infected plant.  Mealy bugs are soft bodied insects that suck fluids from houseplants. Their pinkish-white body is covered with a type of waterproofing making chemical control difficult. They also like to nest deep in the crotches of  a plant, also making control difficult.


Control: Mealy bugs don't reproduce as fast as other insects so you have a good chance of clearing up the problem. Your first line of defense should be physical control. Squish as many of the bugs as you can find with your fingers. Next follow up with a cotton swab dipped in rubbing alcohol dabbing the Mealy bugs that you can't get to. Pay close attention to where the leaf attaches to the stem. Applying systemic granules to the soil and spraying with Safer's Ultra Fine Oil will also help. Repeat this process until you have eliminated all of the Mealy bugs.  
If you have a severe infestation you may need to spray the plant with chemicals.
Hope this helps,Bill