Managing Arborvitae leafminer
What systemic insecticides are registered for SOIL APPLICATION in the management of Arborvitae leafminer in urban areas.
Champaign County Illinois
Somehow your question has made it to an ornamentals and turf entomologist in Ohio. I don't have access to the Illinois pesticide rules. Some states have very strict rules about an insect and a plant being on the label and others, like Ohio, has a site rule. Site rules means that you can use a pesticide on a plant if the plant is allowed on the label and you have a realistic expectation that the active ingredient will be active against the target insect pest. At present, there are three insecticides that I would consider for arborvite leafminer control. Acelepryn, Azatrol and TriStar all have excellent systemic action and excellent caterpillar activity (this leafminer is a small moth larva). Unfortunately, neither Acelepryn nor Azatrol have much activity when applied as soil injections or soil drenches. They have excellent translaminar activity when sprayed. Tristar has some label changes that allow for trunk sprays and soil injection (not drench). The other possibility would be to use the acephate formulation of Lepitec which is also good on caterpillar pests and is applied by soil injection.