Question
Plants in my office -- most recently a ponytail bonsai, have a white powdery and fluffy like substance along the leaves. What is this and how should it be treated?

Answer
Hi Rosemary,

The fluffy white substance is probably related to a mealybug infestation.  From time to time, I have had scale and mealybug infestations on my ponytail palms.  Check to see if you find any insects where the frond (blade) attaches to the stem.  Mealybugs tend to aggregate in these spots.  Mealybug infestation usually produces a clear, sticky substance called "honeydew".  There are many fungi who feed on this byproduct.  The white powdery substance sounds more like a fungal infestation.

Examine your plants carefully for insects.  If you determine that you have mealybugs, use alcohol swabs (or spray) to drench them. This should be repeated several times over a two-week period.  After that, monitor the plants closely.  Isolate this plant from others that you may have in your office, and wash hands (and any shared tools, etc.) to avoid spreading the infestation to other plants.

Good Luck and Good Gardening!