The Andromeda Lace Bug, Stephanitis takeyai,  is a problem specific to Pieris japonica though other lace bug species affect rhododendron, azalea, willow and other landscape shrubs. Originating in Japan, the insect was introduced in the eastern United States in the 1940's. It can be hard to detect early as the insect spends most of its life on the underside of the leaves. Eggs are laid in the midrib on leaf bottom. Up to four generations per year hatch in our area from May to September.  Infestations are more likely to be severe in hot, sunny locations.

Nymphs and mature insects feed on leaves by sucking fluids from them, creating a speckled appearance. A home gardener is most apt to notice the problem in May, on new leaves. If the insect population is dense, the speckles begin to merge and entire leaves turn yellow and drop off. Plants may look dull and ragged, lacking strength. You may also notice the black excretion of the insects on the underside of leaves.

Lace bug can cause severe damage if unchecked to the point of significant leaf loss. The plant will decline in vigor and can die in extreme cases. The egg stage of the insect's development is protected so horticultural oils and insecticidal soaps will have an impact only if the mature insects or nymphs are targeted and thoroughly covered. Give particular attention to spraying the underside of leaves where insects are most populous. If you maintain a chemical-free environment, diverse in plant life and beneficial insects, the lace bugs are typically controlled by natural predators. 

For more information about caring for your plant see our Guide to Japanese Andromeda (Pieris japonica).

Courtesy of NYBG Plant Information Service