|University of Kentucky Entomology|
By Lee Townsend, Extension Entomologist
University of Kentucky Department of Entomology
Hackberry psyllids are small aphid-like insects that resemble miniature cicadas. Also called jumping plant lice, these 3/16" long insects have lightly colored wings mottled with dark spots and hind legs that allow them to jump and fly away quickly. Large numbers of adults may be present in September and October.
Normally, adults spend the winter in cracks and crevices of tree bark. They can be very annoying as they land on people or cars, or attempt to enter buildings in search of a protected areas. They may enter through window screens or small cracks and crevices. These insects do not feed on humans or pets and will not attack house plants, stored products, or furnishings.
There is one generation each year. Psyllids develop on hackberry trees and shrubs, causing distinct raised galls or swelling on the leaves. The immature stages of the insect stimulate abnormal growth of leaf cells causing formation of the gall in which the insect lives and feeds. The gall provides food and protection from many natural enemies. Psyllids within the galls also are protected from insecticidal sprays. Infested hackberries do not seem to be harmed by the galls but severe infestations over several seasons may weaken them. Once development is complete, adults leave the galls to pass the winter. This is when they can be a temporary but very aggravating annoyance.
While these insects can be very annoying, they are harmless, and will disappear within a few days. Dursban, Orthene, and Sevin are labeled to control this insect on hackberry but effective chemical control is difficult to achieve. A preventive approach is based upon trying to kill newly hatched nymphs before the onset of gall formation.
Egg-laying occurs over a period of several weeks beginning when new leaves unfold from the bud. Several applications of an insecticide would generally be necessary to keep an insecticide residue on the expanding leaves during the entire period that eggs are hatching. Spraying of large trees is difficult and without powerful sprayers, it is difficult to get the good coverage that is needed. There are some systemic insecticides that can be used by commercial arborists if necessary. If chronic problems occur, removal of the source plants may be worthwhile.
CAUTION! Pesticide recommendations in this publication are registered for use in Kentucky, USA ONLY! The use of some products may not be legal in your state or country. Please check with your local county agent or regulatory official before using any pesticide mentioned in this publication.
Of course, ALWAYS READ AND FOLLOW LABEL DIRECTIONS FOR SAFE USE OF ANY PESTICIDE!
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