Please help save my begonias!

[colorfulbegonia]

I have an urgent question regarding my wax begonias (the flowering type). I have had them for a few years and they did well inside with plenty of flowers. :) However, things changed a couple of months ago when I purchased another begonia plant of the same type. At the time of purchase I noticed that some leaves had some rusty spots on them but didn't think this was anything major. Unfortunately soon, this spread to my other begonias which are doing very poorly now. They have stopped growing and when they are any new leaves, usually they are very small and they die shortly after. :( Needless to say that there are not flowering at all. There doesn't seem to be any insects involved (I have already used an insecticide). The only visible sign of disease is the rusty spots (of varying sizes) on the older leaves. Please help :!:

Thank you :!:

[Newt]

Hi Colorful,
I'm wondering why you sprayed an insecticide. Did you see evidence of bugs? I always say "know thine enemy". It sounds like a fungal problem that you are having. Take a look at these conversations and pics to see if it's the same thing. You can click on the pics of this first one to enlarge. Sorry that some of the pics in the second link don't show.

http://www.geocities.com/marielabegonia/my_begonia.html
http://forums.gardenweb.com/forums/l...4529799.html?7

For a homemade fungal spray, take a look here.

http://www.dirtdoctor.com/view_question.php?id=204

Hope this helps,
Newt