Blackfly and Broad Beans

This season I sowed a variety of broad beans "Grano Violeta" as I couldn't get my usual "Bunyard's Exhibition " from the seed supplier I used. Then, I came across some Bunyard's in a garden centre, and bought them. Sowed them next to the " Grano Violeta". They were very close to each other, touching in places. As they grew, the Blackfly arrived! They smothered the Bunyard's, but hardly touched the "Grano Violeta". This prompted the question, are some varieties more resistant to Blackfly? Has anyone else experienced this, or got any thoughts on it?

I only grow the Sutton as our site is exposed and they cope best with the wind. It seems to have been a year when there has been more blackfly than usual. However the usual remedy of picking off the top three inches of the plants has saved my crop. I haven't grown the variety you are trying but I have grown Bunyards Exhibition before and they were okay re: blackfly. Maybe this year has just been a bad year fro blackfly?