Lilac Borer Infestation: Diagnosing Without Photos and Treatment Options

Likely Culprit: Borer Insects

Wood pieces at base + curled leaves + small holes = lilac borer (or similar clearwing borer) larvae tunneling in stems.

Borer larvae inside wood are protected from contact sprays.
Systemic imidacloprid (soil drench) moves into stems, killing feeding larvae.
Apply early spring before adults emerge.

Water during drought, mulch, avoid wounding stems. Healthy lilacs resist borers better.

Plant Diseases: Lilac Sudden Leaf Curl and Decline: Multiple Possible Diseases + Neighbor’s Overwatering; Scale Insects Masquerading as Fungus on Lilac; Powdery Mildew on Lilac: Identification and Treatment; Roundup Drift on Lilacs: Recovery Possible; Propagating Lilacs: Hardwood Cuttings, Layering, and Suckers; Overwintering a Potted Lilac on a Balcony: Zone-Dependent Advice; When to Prune Lilacs for Maximum Blooms; Lilac Bush Budding in Late July: Stress or Second Bloom?; Rescuing Drought-Stressed Lilac in NE Ohio; Why 'Sensation' Lilac Blooms White Instead of Bicolor

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