I'm not sure, Lynn. All of those pests and diseases depend on your location, don't they? I know that in the case of roses, I'd have to say that everything in my garden gets black spot, but Skiekitty can grow the same roses in Colorado and never see a bit of black spot. Same thing with pests. I don't have Japanese beetles, but lots of other people do, so do we mark every single rose susceptible to black spot and Japanese beetles?
I'd like to see some paragraphs on the pests and diseases likely to attack a specific plant on the general page for that genus, but not on each cultivar page.