begonias

[babscartland]

I have wot looks like white meldew all over my begonia leaves. Any thoughts?

[Thunderbird+]

This sounds very much like powdery mildew, which is often a result of plants that are too dry at the roots and have become susceptable to this fungus, when you see it at the powdery stage, the spores are mature and it can spread to newly developing leaves.
Spray with a systemic fugicide or dust with sulphur. remove any severely affected leaves and dispose of (burn if possible) Good Luck Tbird+

[Clanad]

As usual, I'm two steps behind Thunderbird, but it sounds like you have (actually your begonias have) Powdery Mildew:

Read here:
http://plantclinic.cornell.edu/FactSheets/powd ery/powdery.htm

It's probably too late in the season to due anything very helpful, however, be sure to thoroughly remove all leaf and plant residue when doing the fall clean-up.. Additionally, next spring, at the first sign of thaw (if your area freezes) spray the ground area with a product known here in the U.S. as Dormant Oil. It's a foul smelling sulphur compound, but environmentally friendly. Don't get any on your clothes or shoes! Then, next season, if the mildew does re-appear, look for a product called GreenCure�, which is a potassium bicarbonate-based fungicide and is the safer alternative to harsh chemical fungicides. Also environmentallly friendly. A similar product is made from chrysanthemum seeds and contains Neem Oil... one brand we use is Green Light and is very effective... Best of luck!