Roses

Thrips

Thrips are tiny, slender insects (1–2 mm long) with fringed wings. On roses, the most common are Western flower thrips and rose thrips. They feed by puncturing plant cells and sucking out their contents.

Symptoms of Thrip Damage:

- Distorted, deformed, or discolored flower petals (often with brown edges or streaks)

- Buds may fail to open or open poorly

- Silvery specks or streaks on leaves and petals

- Black specks (thrip feces) may be visible on petals

- Damage is most visible on light-colored or white roses

Thrips are most active in warm, dry weather, especially late spring to early fall. They hide inside flower buds, making them hard to detect early.

Cultural / Biological Control

Avoid heavy nitrogen fertilizers that encourage soft new growth.
Deadhead spent blooms regularly.
Encourage natural predators like: minute pirate bugs, Green lacewing larvae, Orius insidiosus (especially effective against thrips).
Promote air circulation by proper pruning.
Remove and destroy infested buds and flowers.

Organic Treatment

Organic

Blue sticky traps: Can help monitor and reduce adult thrip populations.
Insecticidal soap: Spray thoroughly, including into flower buds.
Neem oil: Effective if applied early and directly into buds.
Spinosad-based sprays: A more potent organic option, safer for beneficial insects when used properly.

Chemical Control

Spray timing is critical: Early morning or late evening, and target young flower buds.
Use systemic insecticides or contact insecticides labeled for thrips (only if infestation is severe): Spinosad (also considered organic), Pyrethrin (less toxic, fast-acting), Imidacloprid (systemic—absorbed into the plant).

Prevention Tips

Combine treatment methods for best long-term control.
Inspect new plants before introducing them to your garden.
Monitor blooms regularly—especially pale varieties.
Use thrip-resistant rose varieties when possible.

Rose Care