Bug damage to Tamarack

I have about 450 seedlings I transplanted last spring and some are showing damage from the bugs, no damage last year. No natural tamarack in the surrounding area, not many places to migrate from. They’ll move to another section next spring, had some moving around before.<br><br>Some seedlings are not affected, is that a sign of resistance? It seems like the ones that were more exposed and the border ones were damaged. What should I do next year? Protect them for a couple of years before moving to another plot or set or a different tree and move the tamaracks to a different spot? The ones with damage are still growing fine.<br><br>I've sprayed some with liquid Sevin, and Malcolm.<br><br>I've moved 36 seedlings to a plastic covered greenhouse.<br><br>Do you think it's a good idea to grow some in containers and move them to a different location each year.<br><br>I have about another 400 seedlings in plug trays to be planted next spring.<br><br>First year of this bug damage