Cactus Loghorn – Moneilema armatum

Cactus Loghorn (Moneilema armatum) Latin Name: Moneilema armatum Common Name: Cactus Loghorn Appearance: These beetles’ front wings are united, producing a single, solid shell from which they derive their name. Larvae penetrate the roots and stems of cacti, killing more vulnerable individuals. Adults eat on the surface of the cactus as well. They are primarily black, with white elytra that is speckled. Pupa Pupation happens inside the cactus on which they fed as larvae, and they overwinter at this time. Egg The female beetle lays eggs in various areas of the cactus. Larva The larvae have brown heads and live within the stems or roots of their host plants. Host plants: Cacti, mainly prickly pear and cholla, are the host plants Territory: These beetles are found in the North American desert Damage caused by Cactus Loghorn: The larva bores into the cactus, producing root and stem damage. They emit a green material that hardens and becomes black while digging. The cactus is harmed by this chemical, which softens its tissue. Life history and Habits: The cactus longhorn grows by eating cacti from the genera Opuntia and Cylindropuntia. They spend the winter in a pupal cell that they build around the cactus base in late summer and early fall. In the spring, they develop into pupae, and adults emerge in the late spring and early summer. Adult beetles feed at night, usually on young cactus pads or sap. Females bind eggs to the cactus pad after mating. The immature larvae dig into the cactus, causing the plant to exude sap from the wound. The juvenile larvae eat initially in this sludge before entering the plant. Normally, one generation is generated every year. However, some later larvae may not emerge until the second season.