"Bob Hobden" wrote

"Jake" wrote

"Bob Hobden" wrote:

Just noticed there is the first signs of Powdery Mildew attacking the
leaves
of some of my Tuberous Begonias. It's normally an autumn thing but I
assume
this unusually cold wet weather has brought it on early. Everything I
look
at in the Garden Centres specifically says not to be used on Begonias, or
it
does when you search the manufacturers web site.
These are some expensive show begonias and some I inherited from my
mother
in 1993 so I don't want to lose any of them.
Anyone know what I can use to cure or prevent it spreading?


According to RHS, there are now no effective curative fungicides
available for domestic use anyway. But I BELIEVE that Bayer Fungus
Fighter Disease Control is OK to use on begonias and has some
preventive impact - you should be using it almost as soon as leaves
emerge sort of thing. If the infection is very recent, though, it may
help. I've checked Bayer web site and they don't say "not on begonias"
for this product but suggest you check with Bayer Customer Services to
be sure.

Otherwise it's a case of quick removal of any infected leaves and all
fallen plant matter, drying the atmosphere, creating air flow
(removing some unaffected foliage may mean they're not show worthy
this year but be life-saving for next) and crossing fingers.


I think that contains Myclobutanil and looking at the RHS Advisory Leaflet
it says "Do not use on fuchsias, begonias, asters, solidago and young
seedlings". Similar for anything containing Difenoconazole.

Perhaps I'll try the 1 part (full or skimmed) milk to 9 parts water, or
maybe the Bicarbonate of Soda spray, (1 tbs baking soda, 1/2 teaspoon
liquid soap to 1 gal water) but I think that would need to be tested first
on one plant.

What I can't believe is it has appeared first on the plants that have been
outside for 3 weeks so hardly dry at the roots or lacking in air movement!

Now received a reply from Blackmore and Langdon (top begonia specialists)
and this is what they say should anyone else have this problem...
"Sorry to hear your having a problem with mildew, this can be a nightmare
and there doesn't seem to be any rhyme or reason as to why and when it
appears.
We have been recommending and selling a product called 'Fungus Clear Ultra',
certainly works very well on begonias we have treated here. I am pretty sure
you can purchase this in the garden centres but if you would like to save
the hassle of hunting for it I can post you a pack (enough to make 15
litres)."

-- Regards
Bob Hobden
Posting to this Newsgroup
from the W.of London. UK