Question
QUESTION: I have a large plant I believe to be of the palm tree variety. It has fuzzy white stuff on the underside of the leaves. At first I thought it was mealy bugs but,the substance is not cottony more like fuzz and when I rub it together between my fingers it just vanishes leaving no residue on my fingers. Other then that the plant is very healty and has new stems growing, its over 4ft tall. This fuzz is not on ever leaf, but on several

ANSWER: Hi,

sorry for the delay in answering, but we are beginning the spring semester at the university.

It is very, very unusual to have any insect to leave absolutely no residue, so what you are dealing with is probably not biological in origin.  There are other insects that resemble (in their juvenile stages)mealy bugs.  They are closely related, and they are called scale insects.  These are often more visible in their juvenile (white, fuzzy) form than in their adult morphology, oval to round, hard, and flat.  If you have any stickiness on the fronds of the palm, you probably are dealing with scale insects.  

So, what should you do?  I guess that is why you asked, huh?  The only thing that I could recommend is to observe the plant very closely for the short term.  If you notice any yellowing of the fronds, examine even more closely for insect infestation.  The fuzz is obviously coming from some where, either fungal or an insect waste product.  If the fuzz is grayish to black, it may be some sort of fungus which feeds on the sticky residue left by the scale insects.  This may explain why you feel no stickiness on the plant.  Fungi usually are not specific to the underside of the fronds, but they may favor a more shaded spot.  

I am really sorry that I cannot be more specific, but without any photos, it is hard to tell.  If you have access to a digital camera, you may send me a photo at:

[email protected]

Good Luck!

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

QUESTION: Thanks for getting back with me. While waiting for your response I looked at some of the other Q & A from other people, and noticed one thing you told a man name David inquiring about something similar on his philodendron, you said it could be powdery mildew. Could this be my problem? In the mean time I wiped off all leaves with some diluted alcohol, some possible cure I found on another website, I searched so many that day. Anyway I don't know if this worked but it didn't make it worse, and I cant send you a picture because I wiped away all evidence. If the problem or stuff return, I will send you a picture. Wish me luck

Answer
Hello again,

Thanks for getting back to me.  Yes, it is quite possible that what you are seeing is a fungal infestation.  Powdery mildew, however, is not specific to the underside of the leaf; it can be found anywhere on the leaf.  Some plants are more prone to powdery mildew indoors when there is a relatively high humidity coupled with low temperatures.  (Believe it or not, these conditions are often the case in winter.  As the night temperatures drop, the relative humidity rises.)

Powdery mildew, if that is your problem, will not be reduced by the use of alcohol.  Luckily, it won't hurt the plant.  If you have a fungal infestation, you can use sulfur dust to cover the leaves (a light dusting on both top and undersides of the leaf.)  That is a relatively inexpensive, safe measure.  

Earlier in the fall, I had a problem with an African violet that had powdery mildew.  I simply removed it from the rest of the plants (assembled plants maintain higher humidity), reduced the amount of water so that the surface was dry, but the potting mix was moist at a depth of 1/2 inch--one knuckle.  After about a week, the white blotches simply disappeared.  This was because of the environmental requirements of the fungus.

Just an added thought.  Powdery mildew is not usually a serious problem on palms.  

Hope all goes well.