Spider Mites and Whiteflies on Indoor Dahlia and Mystery Plant

Dahlia pompon shows severe webbing, leaf damage. Second unknown plant releases clouds of tiny flies when shaken. Both indoors.

Diagnoses

• Dahlia: Severe spider mite infestation (webbing, stippling).
• Mystery plant: Likely whiteflies (tiny, fly when disturbed).

Integrated Treatment

• Reference: UMN Extension fact sheet on houseplant pests (link).
• Non-chemical: Wash/scrub plants, remove webbing.
• Chemical: Select products labeled for spider mites AND whiteflies. Rotate modes of action.
• Application: Spray outdoors, cover all surfaces (especially undersides). Repeat 2-3× at weekly intervals. Keep outside 1 week before returning indoors.
• Severe dahlia: Cut back heavily to remove webbing before spraying.

Critical Success Factors

Thorough coverage, multiple treatments, product rotation, and isolation during treatment.