Question

Whenever possible, it's best to avoid adding diseased plant matter to a compost pile. That said, some diseases are less worrisome than others. For example, I don't have any problem adding squash leaves that have been affected by powdery mildew, but I would never consider adding tomato vines affected by late blight.  Another consideration is what type of composting you do.  I don't have any scientific basis for thinking this, but I feel that if you're using hot composting there's a better chance of killing off whatever potentially harmful bacteria you might add through some diseased matter.  My 2 cents.

I agree with Roger.  Composting to 140 f. will kill most harmful bacteria, but I wouldn't put blighted tomato or potato vines into my compost.  Not worth the possibly of spreading blight. Stay natural, David

I agree. Ask your Extension Specialist or vegetable Pathologist they keep records of this type of thing. Also tell them how your compost works out next year.