At what stage should you pinch out the tops to deter blackfly? Before the blackfly appears or after? And even if you don't have blackfly, should you pinch out the tops anyway and what effect does this have on the yield?

Something for the experts!

Pinch out the tops before the blackfly descend and start sucking all the juices out of your plants. I would pinch them out anyway as you don't know when the little divvels will arrive.

I don't think it affects the yeald too much as the flowers should be pollinated and well on their way to producing pods. The tops are quite tasty lightly boiled or steamed (with added black protien or no) !

Cheers, Tony.

The tops of Broad Beans make very good eating when steamed and nipping out the tops will allow the plant to consensentrate on putting energy in giving a better bean crop. I auotomatically take the tops out as soon as the flower begins to form. Thankfully we do not seem to be bothered by Blackfly here and have not had an attack for many years now on anything. When the crop has been taken I always cut the haulms back to around 4" to 6" from the ground and they regenerate and give you a nice autumn bonus. Not many beans but well worth the effort.
JB.