Yes, these are the worst pine-needle pests IMO. They can defoliate a small seedling (or an entire branch on a larger tree) overnite and can attack anytime from late spring to autumn. I've also got problems w/dogwood sawflies.

Give em HELL calliope!! Do not feel guilty.

Do you find that they focus on the bottom, middle or top of the pine?

I'll have to keep an eye out for them. I have quite a few pines (more dwarf though).

These little son of a guns were clustered on each branch tip last year all over the tree, and ate the needles down methodically like eating corn on the cob. We knew something was up when it went from full to nekkid in a matter of days. They're such a good match for the green of the needles and align themselves in such a way as to mimic the needle orientation. This is perhaps a ten year old tree and planted on a slope, so I was able to get good coverage by hitting the crown section working above it on the hill.