Lilac Disease and Pest Problems
Lilacs are hardy plants. Most insect pests do not bother them to any serious
degree. For occasional insect problems, such as aphids or borers, treat with
an insecticidal soap or a mild insecticide, like Sevin. Ants will appear,
sometimes in large numbers, during the blooming period. They are seeking
the sweet nectar in the flower, and do no harm to the flower or plant.
Lilacs are susceptible to Cicadas, which occasionally emerge in huge numbers,
in areas east of the Mississippi. If large broods emerge in your area, you
will want to cover them with 1/4" pest netting during the emergence.
Mice and voles (see moles and voles)
are one of the biggest pests of lilacs. During hard winters, they will chew
on the bark of the stems at or near ground level, and can kill the plant.
They harbor under the mulch you amply provided, and feed on your plant,
especially in the harshest of winters.
Diseases of Lilacs:
Lilacs are susceptible to a couple of plant diseases. Most common is powdery
mildew. Powdery mildew occurs most frequently during hot and humid weather.
Treat any outbreak early. Apply a general purpose fungicide two or three
times about a week apart, as soon as the problem is spotted. For major outbreaks,
trim away infected branches and dispose of them.. Do not add them to the compost
heap. While this disease can cause major problems with more tender fruits,
flowers and vegetables, it will generally not cause long term or serious
problems for your bush. Powdery mildew's unsightly appearance is the biggest
negative for Lilacs.
More Gardening Resources:
Lilac Bushes select from popular Lilac varieties