Dr. Phyto

common lilac

Syringa vulgaris

Diseases & pests on this plant

• bacterial blight / canker (multi-host)Pseudomonas syringae pv. syringae

  Brown-black angular leaf spots with yellow halos, blackened buds + young shoots that fail to open, sunken brown cankers on stems with bacterial ooze in spring, blossom blight in cool wet bloom periods, branch dieback in heavy infections.

• Lilac powdery mildewErysiphe syringae

  A thin, white to greyish powdery coating (fungal mycelium and spores) develops on the upper, and sometimes lower, leaf surfaces of Syringa vulgaris, usually appearing from mid-summer onward and most severe in late summer and autumn. The coating wipes off easily with a finger, leaving the green leaf beneath. Heavily affected leaves may yellow, become dull or slightly distorted, and on late-season foliage tiny pinhead-sized fruiting bodies (chasmothecia) appear as scattered dark amber-to-black dots within the white mat. The disease is mostly cosmetic and rarely kills the shrub, but persistent infection on young growth can reduce vigour and flower-bud quality.

• olive Verticillium wiltVerticillium dahliae

  Half a tree wilting in summer while the other half stays green, blackish discoloration in cross-section of affected wood, partial recovery in winter then relapse, dieback over 2–4 seasons.