Several applications may be required to provide adequate protection. Imidacloprid, applied as a soil drench, will provide season-long systemic control. Consult the labels for dosage rates and safety precautions. Cankerworms , Alsophila pometaria and Paleacrita vernata Cankerworms feed on hawthorn foliage during the spring. In early spring, caterpillars hatch from the eggs laid on the trees in late fall or early spring.
Older caterpillars are black or greenish with stripes.
Each species has only one generation a year. The abundance of cankerworms varies in cycles. The caterpillars can be controlled with one or more springtime applications of azadirachtin, carbaryl, Bacillus thuringiensis var. Consult the labels for dosage rates and safety precautions. Cottony maple scale, Pulvinaria innumerabilis .