Epilachna varivestis also commonly known as the Mexican bean beetle, lives up to its name due to the destructive nature of bean plants the pest causes.
The bean beetle and their larvae young feed on the undersides of the plant's leaves, and have even been known to destroy the pods and stems of the plant. Their damage is so severe that the bean plant's leaves have a skeletal-look after feeding.
The adult bean beetle is ¼ inch long and has often been mistaken for a ladybug due to their oval shape,copper-brown color, and black spots.
Their larvae can grow to ⅓ inches in length, are orange in color, and grub-like with spinal rows that run along the length of their back.
The adult beetle will start to appear during late spring when the temperatures begin to warm up and bean plants begin sprouting.
After a 2 week feeding, females will lay their eggs in clusters on the underside leaf of the bean plant. The eggs hatch in 5 to 14 days and the young larvae feed on the leaves of the plants until they pupate on the underside of the leaves. In about a week, an adult bean beetle emerges, starting the reproduction and feeding process once again.
Because the damage is at its worst during the summer, one way to prevent a beetle infestation is by planting beans that can be harvested before the weather turns hot.
You can pick the adult bean beetles and their larvae off the plants by hand to reduce damage. Look on the underside of the leaves for yellow egg clusters and gently sweep them off into a bucket of warm soapy water, which helps destroy all stages of the bean beetle.
If you already have a major infestation of the pests in your garden, try introducing beneficial bugs such as ladybugs and minute pirate bugs, both predators of the bean beetle's eggs and larvae. Repeat if beetles continue to be heavily noticed in your garden.