Today I removed a coneflower that I thought had herbicide damage, but now discovered it is probably aster yellows (had never heard of this disease until recently.) I have used weed-b-gon, using a paintbrush to try to get rid of the thistle that is impossible to get gone by digging. By using a paintbrush, I don't believe any would have gotten on any of my plants nearby, but at first, that was my assumption. I have attached a photo of the coneflower that was removed. I also pulled a sunflower plant with unusual growth and symptoms of aster yellows. I am wondering if I should remove two garden phlox with unusual curling of the leaves. This is the second year with weird leaves. I cannot find any insects in the undersides, though I do have a problem with aphids on other plants. The flowers seem to be forming normally. Do you think think this could be herbicide damage? Or does this look like aster yellows or some other disease? I'd rather not remove the plants if it isn't disease, because they are a lovely color and I really enjoy them. But if they are diseased, the sooner they are gone, the better. Anyone with experience with aster yellows? or have phlox which have looked like this and recovered?

Here is the phlox. Sorry it's hard to get my camera to focus on the plant.

The sunflower

And lastly, the coneflower