I bought a two year old linden tree from a local nursery and had a tree expert plant it in early June to replace a diseased maple that had to be cut down.  It arrived with drooping leaves and within two days, showed symptoms of transplant shock (first photo). I amended the soil, watered the tree and sprinkled the leaves with a hose as directed. The browning of the leaves didn't get any worse. But last week, something started defoliating the leaves. (second photo). Can you tell me what is doing this? I thought maybe it was sawflies but I can find no larvae or bugs on the tree.