Native to Japan, the azalea lace bug (Stephanitis pyroides) was introduced to the United States in the early 1900’s by the movement of its host species, azaleas.  The azalea lace bug has become a destructive pest to azaleas in the eastern United States. 

This bug causes damage by sucking out the fluid of the leaves from the underside.  This feeding creates injury to foliage including yellow to brownish speckling on the upper leaf surface.  Severe injury may result in early leaf drop.

Susceptible Hosts
    Azalea (Rhododendron spp.)

Pest
Stephanitis pyroides

Symptoms
* Discolored spots or bleaching of the upper leaf surface.
* Leaves can become whitish, dry up, and fall off in severe infestations.

Signs
* The adult is 1/8 inch (3mm) long with light brown legs and antennae.  The  wings are transparent and lace-like with brown and black markings.
* Nymphs may be found on the underside of the leaf surface.  Nymphs are colorless as they emerge, but soon turn black and spiny. 
* Deposits of hard, dark, varnish-like spots of excrement may be found on underside of the leaf surface, especially along the leaf veins where the female inserts her eggs.
* Eggs are white, smooth, and flask shaped with a neck to one side.

Life Cycle
* Nymphs hatch in early spring and begin feeding on the underside of the leaves before molting 5 times as they become adults.
* Adults mate and the females lay eggs in the tissue on the underside of the leaves along the veins by mid-summer.
* Depending on location, there may be a third generation that occurs in late summer or early fall.
* Two or more generations occur.
* The eggs of the last generation overwinter in the egg stage on the underside of the leaves along the veins.

Distinguish from Look-alikes
* Similar speckling is caused by mites, which feed on the upper surface primarily; Mite damage, however, does not stain the lower leaf surface.
* Azalea lace bug is very similar in appearance to several other lace bug species.  Proper identification of host tree is the distinguishing factor.

Azalea lace bug eggs hatch in early spring and the nymphs begin feeding on the underside of leaves. Soil applications of Xytect or Transtect will provide a high level of control and are the recommended products of choice. 

Apply Xytect in late summer/early fall for next year control or apply Transtect in early spring to ensure high titer levels are within the tree at the time the nymphs emerge.  Arborists should only use foliar sprays for immediate activity against the insect.  Thorough coverage on the underside of the leaves is essential for good control when applying foliar products.

Expectations:
* Xytect and Transtect will provide a high level of control vs. lacebugs.  
* Insecticides will not restore an undamaged appearance, but can reduce or prevent further damage.
* Lacebug activity results in a large amount of debris on the undersides of leaves, this can often be mistaken for lack of control, do not mistake this for lack of performance. 
* Almost any insecticide will control lace bugs if it is sprayed directly onto the insect, however thorough coverage on the underside of the leaf is required.  Multiple spray applications may be required as well making soil applications the product recommendations of choice. 

Other Treatment Practices
* Promote health and vigor with proper irrigation, mulching, proper pruning and prescription based fertilization practices.
* Plant lace bug susceptible host plants in areas of the landscape that are shady.  Lace bugs tend to prefer host plants in bright, sunny areas.
* A hard jet of water from a garden hose can dislodge the young nymphs after hatching in the spring.

University of Florida

North Carolina State University

Ohio State University

University of Minnesota