Question
My palm has white, cottonie substance on leaves.  Do you what it is and how to treat?  I can send picture if you have an email address.

thanks
JP

Answer
Send the pictures to [email protected] and I will see if I can ID the problem .
Got the pictures thanks!
It looks like mealy bugs which is a  soft bodied insect. They suck the juices from the leaves and form this cottony like substance which gets on the plant.  These insects are easily controlled by using an insecticide for mealy bugs . There are several avialable that are in a spray container ready to use. Check with your local nursery/garden type store and ask for an insecticide that is ready to use for mealy bugs or aphids. Spray all the leaves on both sides and this should do the trick. I would repeat the spray in a week to make sure you get all of the insects.

This will kill the ones there but not the eggs that may hatch later. For long term control I would recommend using a systemic insecticide that is applied to the soil and the plant takes it up and it gets into the plant juices and as the mealy bug feeds it will die.  One of these is Bayer Advanced Tree and Shrub insecticide .  

Here is a web site that gives you more information on mealy bugs.