Azalea Caterpillar

Tachinid flies glue eggs to caterpillar skin; ichneumonid wasps inject eggs into larger larvae. Spiders and songbirds pick off larvae crawling between branches. If you see fluffy parasitoid cocoons on a leaf, leave that cluster until wasps emerge -- free pest control. Night spraying of pyrethrin across whole hedges kills these helpers faster than it kills late instars hiding inside leaves.

Datana major larvae feed in groups on the interior of azaleas and blueberries -- walk rows in late summer and part the canopy where polite landscaping hides clusters. Early removal of one branch stops headline defoliation later. Flag plants that hosted clusters last year; larvae often reinfest the same genetics. Teach crews to look up, not just at sidewalk edges.

On native plantings, accept minor leaf loss if the shrub still flowers next year -- total control is not always the goal. On specimen shrubs near doors, scout weekly during outbreak years. Avoid nitrogen pushes that make soft flushes; caterpillars still eat, but damage looks worse on lush tissue. After caterpillars leave, water if drought stresses recovery; do not over-fertilize burned leaves.

Clip entire branches with clusters into a bucket of soapy water -- faster than picking thirty larvae by hand. Wear gloves; hairs irritate some people. For small plants, drop sheets and shake branches over them in early morning when larvae cluster. Power-wash is a bad idea on thin azalea bark; you break more than caterpillars.

Bacillus thuringiensis kurstaki works while larvae are small and actively feeding -- spray undersides where groups sit. Spinosad reaches larger larvae if labels allow ornamentals; still avoid spraying open flowers when bees work. Spray at dusk to spare pollinators on blooming rhododendrons and blueberries. Reapply after rain; Bt washes off quickly.