We planted around 100 evergreens about 10 years ago. They are different sizes now. Some as small as 3 ft, some as large as 8 ft. We have watered, fertilized etc. This spring we started noticing new growth turning brown on some of the trees, and dropping off. Then we started to notice a number of the trees just turning brown and looking dead. WE are not sure what is the cause. We have never seen this before. I wondered about Colorado beetles, army worms, mites or is it a virus? WE have been given different advice from different people. We sprayed with sevin and saw no results. We don't know what is killing them, or if we should dig up the ones that are dead or what to do. Please help!!