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Insect and Mite Pests of Honeylocust trees in Colorado

by W.S. Cranshaw

Quick Facts...

Several Insects and mites are commonly found on honeylocust trees in Colorado. However, they rarely affect the health of the tree.
Honeylocust podgall midge deforms new leaves of honeylocust in late spring. One to two insecticide applications when new growth starts can limit this injury.
Plant bugs also feed on new growth and compete with podgall midge.
Late season buildup of spider mites is common on honeylocust. Water sprays, insecticidal soaps and certain miticides can limit this injury.

Several Insects and mites feed on honeylocust trees in Colorado. Their feeding can cause conspicuous injuries that may make the trees unattractive. Heavy infestations can reduce tree growth rate and vigor and cause some twig dieback. However, it is extremely rare that these injuries alone permanently injure the trees. Plant diseases, notably Thryonectria and Tubercularia cankers (fact sheet 2.939, Honeylocust Diseases), are far more important to the health of honeylocust.

Honeylocust Plant Bugs

Figure 1: Adult honeylocust plant bug.

Honeylocust plant bugs commonly infest honeylocust in late spring. This common damaging species of plant bug is generally green. When immature, it superficially resembles an aphid but is much more active. Injured foliage shows yellow or brown spotting. Leaves become twisted, and twig dieback can occur following heavy infestations. The honeylocust plant bug particularly favors new foliage.

This insect can indirectly limit honeylocust podgall midge by destroying gall-susceptible new growth. A single generation of these Insects occurs, with damage peaking in late May or early June. New growth produced after this time emerges normally.

Chemical controls are recommended only when spring growth is seriously threatened, because regrowth occurs in June when insect populations diminish. Orthene, carbaryl (Sevin) pyrethroid insecticides (permethrin, bifenthrin, cyhalothrin) and imidacloprid have been shown to control plant bugs.

Read full article on CSU website.