Hello,

Dwarf Korean lilac (Syringa meyeri) is a lovely shrub which is rarely affected by insects, or diseases, such as powdery mildew Lilacs prefer loose well-drained slightly acid soil. Read more here: https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a286

You can assess the viability of the shrub by the scratch test. The layer of cells under the bark, called the cambium, is moist and green in a healthy shrub but dry and brown when dead. Scratch a small strip off a twig to see if the plant is alive. However, it is difficult to determine what could have caused the death of the shrub from a picture. It could be caused by disease, insect infestation or environmental problems, such as new construction causing damage to the roots or the use of chemicals, herbicides, near the roots.

Healthy roots are white and plump. When the roots are black and withered, the plant is probably dead.

It is, therefore, difficult to diagnose the problem from the picture. A proper analysis could be done at the MSU Extension Plant and Pest Diagnostic Lab. To learn how to submit a sample, go to: https://www.canr.msu.edu/pestid/ The diagnosis will include how to treat the problem.

I hope that this helps you with your lilac.

Thank you for contacting Ask Extension.