Insects with intricate, lace-like exoskeletons cause disturbances.
In the vibrant gardens of Ohio, a small but troublesome pest known as lace bugs can cause significant damage to various ornamental trees and shrubs. The Azalea Lace Bug and the Andromeda Lace Bug are the most common types encountered in the region.
The Azalea Lace Bug, native to Japan, typically infests azaleas. As the insects feed on the lower surface of leaves, they suck juices through slender, piercing mouthparts, depositing a hard, varnish-like excrement onto the leaf surface, known as tar spots or resin spots. Infestation signs include white-yellow stippling on the upper leaf surface and dark, tar-like spots of excrement on the undersides. Azalea lace bugs prefer plants in full sun and are active from late April through the summer[1].
The Andromeda Lace Bug is most commonly encountered on Japanese Andromeda, another ornamental shrub. Eggs are found on the undersides of leaves, and feeding damage appears similar to that caused by the azalea lace bug[1].
Lace bugs can also infest other plants, such as pussy willow, which is known to be prone to aphids, scale, borers, lacebugs, and caterpillars[4].
When dealing with lace bugs, it's essential to make contact with the nymphs or adults, especially during the spring, as this is when the eggs hatch. Insecticidal soaps and horticultural oils can be effective, but it's crucial to cover the underside of the leaves where the nymphs and adults are feeding[2].
For standard insecticides, applications should be made as soon as the eggs hatch, usually mid- to late May, when the danger of frost is over[3]. Some newer systemic products are available that can provide season-long control with a single application.
Monitoring susceptible hosts in full sun locations is recommended for early detection and management. If re-infestations occur, it's important to repeat applications.
Here's a summary of the common types of lace bugs found in Ohio, their common host plants, infestation signs, and active periods:
| Lace Bug Type | Common Host Plants | Infestation Signs | Active Period | |----------------------|-----------------------------|------------------------------------------|-----------------------| | Azalea Lace Bug | Azaleas | White-yellow leaf stippling; tar-like excrement under leaves | Late April through summer | | Andromeda Lace Bug | Japanese Andromeda | Similar feeding damage on leaves | Late April through summer | | General Lace Bugs | Pussy Willow (among others) | Leaf damage, excrement on undersides | Variable |
By staying vigilant and taking prompt action, gardeners can protect their ornamental plants from the damaging effects of lace bugs.
When tending to home-and-garden, particularly ornamental plants such as Azaleas and Japanese Andromeda, it's important to watch out for lace bug infestations, especially during warmer months, as both pests are native to those plants and exhibit signs of infestation like white-yellow leaf stippling and tar-like spots on the undersides of leaves.
