The chrysanthemum leaf miner causes white spots on chrysanthemum leaves (or related plants) which then expand to become white tunnels (or 'mines'). Damage on outdoor plants occurs in May, June or late summer, but indoors this pest can strike at any time. Severe infestations can reduce the healthy leaf surface to such an extent that the plant wilts. Remove affected leaves as soon as you spot them. Insecticides can be effective.
The chrysanthemum leaf miner, Chromatomyia syngenesiae, creates small white spots on leaves, followed by sinuous white tunnels (called 'mines') as the larvae feed on the leaf tissue. Find out more and how to control this pest at oakleafgardening.com