On 22/10/16 10:38, Nick Maclaren wrote:
In article ,
Zephirum wrote:

P. vulgaris (French bean) seems essentially immune, but I get quite
dense localised infestations on P. coccinea (runner bean). What
puzzles me is why they don't spread, the way that they do with broad
beans, and to a great extent most of their other summer hosts. They
don't spread on their winter habitats, of course, but these cases
occur during summer and autumn and look far more like summer ones
than winter ones.

I am a little baffled, I have grown runner and French beans of various
varieties over very many years and have never seen any blackfly on them,
I was told very many years ago that broad beans are best planted in
Autumn as the blackfly seem to prefer the shoots of spring planted
shoots as they are more tender and that seems to be the case. Might it
be geographic in some way? I did most of my gardening in West Cork.

They probably all washed off in the rain :-) More seriously, autumn
planted broad beans don't do well here, because we sometimes get
frost and wind. Bu, on the runners, they attack all of young shoots,
flowering shoots and older stems - the actual growing shoots move too
fast for them! But I have never seen more than one patch every half
dozen plants. Very unlike the way that they attack broad beans.


Regards,
Nick Maclaren.



What type of bean are you planting? I've been using 'Aquadulce' and get
a reasonable crop most winters.