I have a young lilac bush and it is common in my yard to get brown tips on the leaves and they roll up with maybe some kind of eggs inside. Today, after not looking at it for a month or more I went out there and the whole bush was covered in these. I have always been pretty good at removing leaves at first sight of a problem but this is crazy. I would be removing all the leaves at this point. There are lots of little larva in the curls. So, what is this and how should I deal with it?
Have a look at this. http://invasives.wsu.edu/defoliators/host_plants/ornamentals.html After you identify it then you can find suggested controls on the internet searching with the scientific name of the insect.