Almost everyone is familiar with ladybugs. Although, they are usually referred to as bugs, ladybugs are actually beetles. True bugs (order Hemiptera) have sucking mouthparts, where beetles have chewing mouthparts. Recently, ladybugs were reported to be a potential biocontrol agent of the crape myrtle bark scale (CMBS), an invasive scale insect from southeast Asia.
Recent studies have reported a single, fourth instar larva (immature ladybug) can consume up to 400 CMBS eggs per day. Professionals also observed that ladybugs remove 75 to 95 percent of CMBS from infested branches on potted crape myrtles. This scale insect is now found in northern and southern Alabama. Those who suspect they have CMBS populations should report them to their Alabama Extension commercial horticulture regional agent.
Because of their role in biological control, it is important to recognize these beneficial insects. Ladybugs develop through four different life stages; egg, larva, pupa, and adult. The larvae and adult forms are all predatory.
Ladybugs begin life as a yellow-orange cluster of eggs on the underside of leaves. The eggs hatch into small larvae in three to seven days and begin to search for food. These larvae resemble tiny alligators, which can be helpful when identifying them. However, the larvae of mealybug destroyers, a type of ladybug, are white and can sometimes be confused with adult CMBS. Initially these two resemble, but the mealybug destroyer larva is larger and mobile, where CMBS adults are white but they do not move.
In the pupa stage, ladybugs are immobile and usually found on the base of leaves. An adult ladybug will emerge from this pupa stage anywhere from three to 14 days. There are about 10 different species of lady bugs that feed on pests of ornamentals, each varying in color and appearance, ranging from black, red, yellow, orange to brown/tan.
A lab at Auburn University is currently working on developing lures that may attract more ladybeetles and increase their population on an infested tree, which will result in cleaning up the scales. While efforts on that research are on-going, watch out for the ladybeetles on your trees, do not mistake them for a pest. These are tough natural enemies, but some insecticide sprays for CMBS will kill them. If ladybugs are present, consider using insecticides or application methods that will not cause them harm. Applications of insecticides to foliage generally pose greater direct hazard to lady beetles than soil applied insecticides.