On 21 Oct 2016 12:33, Nick Maclaren 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.

Has anyone got any insights?


Regards,
Nick Maclaren.

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.

--
Flying on Per Ardua ad Astra