Q: We have a Chinese pistache with 50-plus holes the size of a small nail. We think they are tree borers; I guess that’s the right name. We went to the nursery and they sold us a Malathion-type insecticide and said to inject the syringe in each hole but that will take forever. Will the borers kill the tree? Is there another way to combat the borers? Will they spread to other trees? We have a great drake elm, and we are worried about that tree. Should we cut down and burn the pistache? . . .