| Lilac Problems | | Symptoms | Probable Causes |
| Leaves Covered With White Powder | Powdery Mildew |
| Leaves Encrusted With Small Bumps | Lilac Scale |
| Branches Wilt and Break Easily | Borers |
| Leaves Turn Yellow | Soil Too Alkaline |
| Leaves Curled And Distorted | Aphids |
| Leaves Mined; Covered With Webs | Leaf Miners |
| Leaf Margins Notched | Weevils |
| Brown Spots; Discolored; Holes On Leaves | Fungal Diseases |
| Leaves Turn Yellow Or Brown | Verticillium Wilt |
| Shoots Branch From Lateral Buds | Witches' Broom |
| Shrub Is Stunted | Too Close To Black Walnut |
| Young Leaves Thicken; Curl; Die | Herbicides In Lawn |
