The oleander caterpillar is a bright orange, a black-spotted pest that feeds on and skeletonizes the leaves of the oleander plant.
These caterpillars feed exclusively on oleander plants, shrubs, or small trees. This is a widely grown, ornamental, and flowering shrub found in the southern and western United States.
Oleander caterpillars start off as clusters of 25-75 yellowish-green eggs found on the bottom of shrub leaves. After hatching, the group of young caterpillars aggressively feed on leaves until they become ragged and thin. The caterpillars then transition to adulthood in a loose, silk-like cocoon found at the bottom of the plant’s trunk. The new insects emerge as distinctive winged moths with a bluish-black body, white spots, and a red stomach. They can be seen hovering over foliage, feeding on the remainder of leaves caterpillars left behind. Feeding occurs in the summer months, with some activity in early winter and early spring.
The most effective management for oleander caterpillars is prevention. When damage is spotted early on, plants can be treated before they fall victim to complete defoliation. For small infestations, remove caterpillars by hand and drop them in a bucket of soapy water. A more severe infestation will need the attention of your local arborist. Treatment must fully cover the shrub foliage, branches, and soil area to successfully eliminate oleander caterpillars. Caterpillars that are tricky to spot or that may have dropped to the ground can easily make their way back to their feeding spot. Your arborist may recommend administering an insecticide that may both eliminate caterpillars and help keep the plant’s health intact.