Begonia, again!

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I lost all my bedding begonias and now the hanging baskets with the
pendula begonias have also got the disease.  I have never seen so many
empty pots in my garden at this time of year.  Can I put the compost
in the compost bin, will the heat kill off the spores?

 On Mon, 22 Aug 2011 03:11:26 -0700 (PDT), Judith in France


This is a different problem from that affecting impatiens - there is
no cure for the latter, unfortunately.

If you have the powdery mildew on your begonias, this may be caused by
the fungus oidium begoniae. It's treatable though at the first sign of
infection (white or grey threads on leaves and stems) you need to
react quickly and cut off the infected bits or remove plants if too
far gone - use scissors if cutting rather than trying to pinch off
with fingers and dip the scissors in meths frequently.

 Don't compost the diseased bits - burn or take to your local tip.
AFAIK, standard fungicides will treat this fungus if applied before it
takes hold - try Roseclear. Granted, this is too late for you now but
be ready next year. I've read somewhere that a 10% solution of milk in
water sprayed on the plants is an organic treatment that works when
the problem is more advanced but don't know whether that needs to be
"full cream" milk :).

Prevention is a case of planting with enough space around the plants
to allow air flow and watering at soil/compost level rather than over
the leaves. And although begonias will grow in shade, a sunny position
is better.

May be ironic that some people are suggesting that begonia
semperflorens will be a substitute for impatiens next year!

Cheers
Jake
==============================================
Gardening at the dry end (east) of Swansea Bay
in between reading anything by JRR Tolkien.

www.rivendell.org.uk

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Thanks Jake, a lot of useful information there.  I will burn the plant
and keep the compost for the composter.