I think the comment you made...

"It seems that all the bugs found on Asteraceae this time of the year are turcicus"

...may be a little over-generalized. This may be the case in your geographic area, but there are certainly some examples in the guide from the western states showing L. kalmii on Asteraceae:



From my own observations of the plentiful population of L. kalmii at my home, I begin to wonder if they are truly as tied to Milkweed as is often assumed. I most typically see the nymphs on Oleander or (even more typically!) crawling on bare ground where they are often not even feeding of plant matter, but instead opportunistically feeding on other dead insects. Perhaps I will put together some of my photos and field notes for a forum post and open it up to some further discussion...