Lace bugs have been showing up quite often in eastern Nebraska. They are a pest of many different types of plants and they can do terrible damage if left untreated and the populations get high enough. There are control methods that can be very helpful if you have a problem with these annoying little insects.
Lace bugs are members of the Homoptera order of insects, commonly called the "true bugs". Other members of this order of insects are boxelder bugs, aphids, and cicadas. Lace bugs look like tiny pieces of lace all over your plants, as the name implies. They are flat insects that are about 3 millimeters long. They are typically white with brown or black markings. The adults may be found on your plant, as well as the nymphs and the eggs.
The nymphs are like smaller, darker colored versions of the adults and the eggs are just tiny black specks that may be found on the leaves. Lace bugs are typically found on the underside of the leaves of many plants including oaks, birches, elm, linden, hackberry, chokecherry, hawthorn, cotoneaster, azalea, rhododendron, sycamore, and the asters including chrysanthemum and goldenrod.
Lace bugs, like all insects that are members of the true bug order, have a piercing sucking mouthpart, which is why they are so damaging to our plants. These insects use a straw-like mouthpart to puncture the surface of a leaf and suck out all of the juices as their food source. When they do this they will reduce the amount of energy and food that a plant has to cause it harm. In some cases, the entire plant may be killed from a large population of lace bugs, but this is usually with smaller shrubs and not large trees.
The damage is typically found on the tree or shrub as white to yellow stippling, or speckling, of the upper surface of the leaves. If the problem is severe, the leaves may turn brown and then fall off. Parts of the plant may also die, but usually most of the plant will survive.
If you notice stippling or speckling of your plant's leaves, look on the underside of the leaves for black specks, small black or lace-like insects. If you find that you have lace bugs, you can treat your tree or shrub for this pest. There are two different methods for controlling this pest on your plants. You can either spot spray or use a preventative method.
The spot sprays are effective at controlling Lace bugs, you need to make sure that you spray on the underside of the leaves, not just on top. This can be done any time of the growing season that you see the lace bugs. A good spot spray is one containing bifenthrin, carbaryl, cyfluthrin, or permethrin. The most common trade names for these pesticides are seven or eight.
As a preventative method, if you have lace bugs on a particular tree or shrub every year, you may want to apply a systemic insecticide to the tree or shrub in the spring. This systemic insecticide should be applied to the soil around the plant so that it is absorbed through the roots and then it will be distributed throughout the entire plant so that when the lace bugs try to feed on the plant, they will feed on the insecticide and die. A good systemic insecticide is one containing imidacloprid which is found in pesticides with the names of Merit, Gaucho, or Marathon.