Hawthorn Lace Bug
Adult -About 3.4 mm long and 1.8 mm wide, the small adult has lacy wings with large, brown areas. The antennae and legs are yellowish (Color Plate 3V).
Egg -The egg is sharply truncate, having the appearance of a small cone. It is smooth, whitish, and semitransparent with a white cap; however, the female often secretes a brownish substance that hardens over the eggs, obscuring their characteristics.
Nymph -There are five nymphal stages distinguished by the varying spines that occur over their bodies. The nymphs are dirty brown, and the later stages become broadly oval and flat.
Host Plants -The hawthorn lace bug feeds on a number of plants in the rose family. It has been reported on apple, button bush, cotoneaster, hawthorn, juneberry (or serviceberry), loquat, oak, pear, pyracantha, and quince.
Damage -Both the nymphs and adults suck fluids out of the leaves from the undersurfaces, speckling the tops of the leaves with yellowish spots. The lower surfaces of the leaves also become discolored with cast skins and excrement (Color Plate 3V). Extensive feeding can cause wilting of the leaves.
Life History -This lace bug is known to overwinter in the adult stage. However, it may overwinter in the egg stage when developing on evergreen hosts. A New England study indicates that development from egg to adult takes about 7 weeks, though the length of time seems to depend upon the temperature. About 40 eggs are laid per leaf in groups of 10 to 30 along the sides or prominent veins on the undersurface. There are five nymphal stages, with only one full generation per year occurring in the New England area. Adults are first noticeable in early May and are found in New England as late as November. They overwinter under leaves, stones, bark, and other natural cover.
Treatment should begin as soon as the lace bugs or their damage is seen. Properly labeled chemicals should be used and safety precautions listed on the labels should be followed. For specific chemical controls, see the current state extension service recommendations.