These sucking insects are occasionally bothersome but usually do not damage landscape plants in California. About one dozen planthopper families (e.g., Acanaloniidae, Delphacidae, Flatidae, Fulgoridae, and Issidae) and more than 100 species occur in California.
Planthoppers are usually 1/2 inch or less in length and have several large spines on the hind legs. Adults commonly have a keel, ridge, or snoutlike projection on the front of the head. Nymphs of some species excrete pale wax on plant parts where they feed. Adult females of some species also cover their egg laying sites with white wax or other excretions.
Planthoppers can be difficult to distinguish from many leafhoppers and spittlebugs, but in comparison planthoppers generally are broader with flatter sides. The location of antennae (below each eye on the sides of the head) distinguishes planthoppers from most other sucking insects. For example, leafhopper, spittlebug, and treehopper antennae occur between or in front of the eyes.
Australian torpedo bug. Siphanta acuta is a harmless, exotic species established in at least southern California. Adults and nymphs are green and up to 1/4 inch long. At rest the adult wings are nearly triangular and the green wings have a pinkish outer margin. The nymphs excrete pale wax from their rear end.
Spotted lanternfly. Lycorma delicatula is a damaging, exotic species to look out for that has established in the eastern United States. Adults are red and white with black spots and have a wingspan of nearly 2 inches. Early instars are black with white spots. The last (fourth) instar is black and red with white spots. The oblong eggs are brownish and laid end-to-end in groups of adjacent rows, but eggs can be obscured by a covering of wax deposited by the female. When abundant, their honeydew and white wax can accumulate at the base of infested plants. For more information see Spotted Lanternfly.
Report any suspected findings of spotted lanternfly in California to the office of the local county agricultural commissioner. For more information see Lycorma delicatula (Hemiptera: Fulgoridae): A New Invasive Pest in the United States, Spotted Lanternfly, and Spotted Lanternfly: A Colorful Cause for Concern.
Planthoppers develop though three life stages: egg, nymph, and adult. Adult females lay eggs in incisions they make in succulent plant parts. After hatching from an egg, planthoppers develop through four or five increasingly larger instars. Wing pads can be distinctive on the last instar, although the coloration may blend with the color of their body. Planthoppers can have several generations per year.
Most planthoppers sucking feed on plant phloem. They can secrete sticky honeydew, whitish wax, or both, which may foul plant parts. The invasive spotted lanternfly that's not yet reported in California can cause plants to die back. It feeds on at least 70 species of plants and can become annoyingly abundant in landscapes. Tree of heaven, Ailanthus altissima, is an especially favored host on which the pest reproduces in great numbers. Crop hosts include apple, apricot, cherry, grape, hops, peach, and plum.
Native planthopper species in California generally cause little or no noticeable damage to garden and landscape plants and are not pests. No control is recommended.
Adapted from the publications above and Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide, University of California Statewide Integrated Pest Management Program (UC IPM).
Adult Australian torpedo bug, a planthopper.
Nymph of Australian torpedo bug.
Adult spotted lanternfly, an exotic planthopper species to look out for.
Last instar (nymph) of spotted lanternfly.