White Veneer on Rose Leaves in Portugal: Mildew or Insects? Drainage First.

Diana in Lisbon: Rose in a vase (pot?) has white veneer on leaves, spreading. Thinks tiny white insects eating new growth.

Critical Question: Drainage

"In a vase" = no drainage holes? Waterlogged roots = death. White veneer likely powdery mildew from stagnant humidity + poor airflow. Or whitefly/mealybug (check undersides for cottony wax or flying specks).

Immediate Fixes

1. Ensure drainage holes. Repot in pot with holes, fast-draining mix.
2. Buy combo insecticide/fungicide at garden center (rainproof preferred). Spray all affected plants.
3. Space plants for airflow. Water at base only.
4. Weekly spray until clean, then as needed.

Long-Term

Roses in pots need: large container (20"+), quality potting mix, full sun, daily watering in heat, regular feeding. "Vase" culture fails.