Adult emergence begins in early May and peaks as new leaves and shoots begin to develop, about the time old leaves naturally drop to the ground on American Holly. Adult flies spend a several days puncturing new leaves with the ovipositor and feeding on bleeding cell sap. In mid May they insert their ovipositors deep into leaf tissue from the underside and deposit an egg. Larval development starts two or three weeks later in June. Larvae develop slowly until mid or late summer when mines develop into a large blotch.
Larval development is complete by fall.
One generation per year. Overwintering stage - larvae. Control Systemic insecticides are highly effective if applied after eggs have hatched. Dimethoate will injure Chinese Holly varieties, especially burfordi, but leafminers do not attack these plants. Remarks Be sure to include a precaution against spraying Chinese Hollies with dimethoate.