While visiting the Genoa Friendship Garden in Harris County Precinct 2, I came across a sycamore (Platanus occidentalis) that was dropping its leaves. Upon closer inspection, there were groups of sycamore lace bugs (Corythucha ciliata) on the underside of the foliage.
The sycamore lace bug is a native North American insect that feeds on sycamore trees. It feeds on the underside of the leaves initially causing a white to silvery stippling that can lead to chlorotic or bronzed foliage followed by premature leaf drop. A single occurrence should not affect the tree negatively, but if severe infestations occur in consecutive years along with other stress factors such as drought then tree death may occur.
Sycamore lace bug gets its name from the lacy pattern seen on the adult’s wings, head, and thorax (chest region). Adult lace bugs are about 1/8 inch (3mm) in length. The wingless nymphs are smaller, oval and are dark colored. Adults and nymphs occur together in groups or clusters on the underside of leaves. The bug’s life cycle consists of seven different stages of development: an egg stage, five nymph stages and an adult stage, and can have several generations in a year. It can overwinter as eggs in leaves or as adults in protected locations such as under bark and fallen leaves and other debris near host plants.
Tolerate lace bug damage when possible, the damage is mostly aesthetic. There are several natural enemies such as assassin bugs, minute pirate bugs, lacewings, spiders and predatory mites. If an infestation occurs on a small tree, spraying with a strong stream of water will get it under control. Controlling this pest on a large tree using chemicals can be expensive and may not be practical. If an application is needed and feasible then systemic products with active ingredients such as acephate, dinotefuran and imidacloprid are recommended. If you prefer to use a contact, nonresidual pesticide then the following active ingredients are recommended: azadirachtin, insecticidal soap, neem oil, and pyrethrin products. Read and follow the product label instructions for safe and effective use.