[Candide]

Pulled up all the second sowing of broads on Saturday cos overrun by blackleg.  Thing is I've already got some dwarf French in the same patch.  Will they get it as well ... are they doomed?

[JayG]

Assuming you mean chocolate spot disease. 

If so, it won't affect your French beans - Good old RHS!

(If you meant blackfly, the French beans could be affected, but spraying with very dilute washing up liquid is helpful, although you will probably have to spray more than once until they are under control.)

[Candide]

Thanks Jay;  no aphids here yet astonishingly.  Dumped the broads in the landfill bin