If you observe water-soaked areas on boxwood leaves developing into blisters on the lower surface, which pest is most likely present?

• A. Boxwood leafminer.
• B. Azalea leafminer.
• C. Scale insect.
• D. Mites.

Answer: (A)

Leafminer damage starts with areas that look water-soaked on the top of the leaf, then the tissue swells into blister-like patches on the underside as the larva feeds between the leaf layers. Boxwood leafminer specifically targets boxwood and creates these characteristic blisters on the lower surface as the larvae develop inside the leaf. The other pests don’t produce that exact combination of symptoms on boxwood: azalea leafminer would affect azaleas, scale insects show up as stationary bumps with possible honeydew, and mites cause stippling or bronzing rather than distinct blisters on the underside. So the observed pattern points to boxwood leafminer.