Diagnosing Deformed Rose Buds: Concentric Holes and Petal Damage

One white rose bush out of 25 in Grand Rapids, Michigan, produced buds that became terribly deformed with concentric, cone-shaped holes through the petals. The outer petals were damaged, but the flowers eventually opened. No Japanese beetles were present.

Identifying the Pest

Damage patterns point to specific culprits: a small hole at the bud base suggests rose midge; shot-hole patterns indicate weevils; tiny brown spots are thrips; ragged edges point to caterpillars; deep holes in open flowers suggest beetles or earwigs. The concentric holes described align with rose midge or weevil activity.

Targeted Treatment

Any rose insecticide will control these pests, but application technique matters. Spray thoroughly around the base of the plant, where eggs are laid and larvae emerge. Horticultural oil is an effective organic option that suffocates insects at all stages. Because the same bush is affected yearly, the pest is likely overwintering at its base—target that zone.