They are lace bugs. Adults are ¼ inch long. If you examine them with magnification, you will see they are well-named, having very ornate, sculptured wings. The immature nymphs are similar but are smaller and lacking lacey wings. Lace bugs are active in the spring but their damage is usually not noticed until later in the summer. In addition to chokecherry, hackberry, and white oak, lace bugs also feed on many other ornamentals in Minnesota, including walnut, basswood, bur oak, willow, hawthorn, juneberry (amelanchier), and cotoneaster.

Lace bugs have needle-like mouthparts that they insert into the underside of leaves. As they remove chlorophyl, they create very small whitish or yellowish dots on the top of leaves. As they feed, this discoloration takes on a speckled appearance. If the feeding becomes severe enough, leaves can take on a bleached look. Severely affected leave can also drop prematurely. The black dots are lace bug droppings. The more severely a leaf is fed on, the more droppings will be present. Droppings, by themselves, are not harmful to shrubs and trees.

Fortunately, lace bugs usually do not seriously injure trees or shrubs. Woody plants can easily tolerate lace bug feeding in one year without significant impact to their health. However, persistent, heavy infestations over several years could slow growth and damage shrubs or trees. Also, if you have a young, recently transplanted plant or an unhealthy, stressed one, lace bug feeding in one year will have a greater impact on plant health.