- Lilac leaf miner, leaf miner or lilac moth (Gracillaria syringella)
- Lilac leaf weevil, vine weevil (Otiorhynchus rotundatus)
- Hornets (Vespa crabro)
- Gall mites (Eriophyes loewi)
Even if the popular ornamental shrub lilac is considered hardy and robust, it is not immune to diseases and pests. In particular, if brown spots appear on the lilac leaves, you should first think of a pest infestation and then search the shrub for it. In this clear summary you can find out which pests are particularly common on lilacs and what you can do about them.

Lilac leaf miner, leaf miner or lilac moth (Gracillaria syringella)
The leaf miner is an inconspicuous, small butterfly whose pupae overwinter directly on the lilac. The larvae finally hatch in May and feed primarily on the leaves. They can also be found less frequently in the soft drive axles. Leaf miners are not only very common on lilacs, although the first generation usually leaves little damage.
- Symptoms: olive-brown spots on leaves, dying and turning brown leaf parts, destroyed leaf tissue, yellowish larvae in the leaf
- Control: not necessary in normal cases, spraying when sprouting
Lilac leaf weevil, vine weevil (Otiorhynchus rotundatus)
This is a red-brown beetle up to six millimeters long that only feeds at night and spends the day under leaves and other hiding places on the ground. Its larvae also live in the soil and can severely damage the roots due to their hunger. An infestation can only be detected with tricks: Place a clay pot filled with wood shavings under the lilac, the vine weevil will use this as a hiding place and you can collect them.
- Symptoms: eroded leaf edges
- Control: Collection, treatment with neem possible in the case of severe infestation, use of nematodes such as roundworms of the Heterorhabditis genus
Hornets (Vespa crabro)
Hornets mainly use wood or bark to build their nests, which they peel from the trees themselves - for example lilacs.
- Symptoms: peeling or feeding spots on the shoots, very rarely wilting leaves and dying branches
- Control: only useful in the case of a large-scale infestation. Hornets are under protection and should therefore be left alone
Gall mites (Eriophyes loewi)
These are tiny mites, only about 0.2 to 0.5 millimeters in size, which belong to the arachnids and feed on plant sap.
- Symptoms: light green discolored leaves, thickened buds, short shoots, formation of "witches broom"
- Control: remove affected leaves, spray shoots with rapeseed oil preparation (neem) in early spring, loosen the root disc, plant wild garlic
tips
If no pests can be found despite obvious damage to the lilac, in many cases a fungal infection is behind it.