Blue Cactus Borer – Melitata dentata

Blue Cactus Borer (Melitata dentata) Latin Name: Melitata dentata Common Name: Blue Cactus Borer Host plants: Prickly pear cactus (Opuntia spp.). Territory: Throughout in United States. Damage caused by Blue Cactus Borer: Larvae are dark blue caterpillars that tunnel into the cactus pad at the base of the needles. They dwell and grow within the pads, generating a lot of frass near the openings. Life history and Habits: Adult female moths deposit eggs in an odd “egg stick” mass along the spines of prickly pear cactus during the summer. They spend the winter as a partly developed larva and resume feeding when the temperature warms up in the spring. As the larvae grow, they disperse throughout the plant, targeting neighbouring pads. They can sometimes be so numerous that they destroy the cactus pads or perhaps the entire plant. The larvae of the blue cactus borer are a unique blue hue, earning the bug its popular name. When the larvae fully grow, they leave the pad in late June or July and move rather far away from the plant. They pupate in a cocoon beneath the debris. Adults usually emerge in mid-July and can be found until August. The egg stick masses are placed on the spines after mating. Each season has one generation.