Lace bugs sound like the sweet, grandmothers of the insect world. They should be the sort of bugs that spend their lives sunning themselves on broad leaves, supporting gardens, and making the whole yard cozy.
But these sapsuckers aren’t the grandmothers of the garden. They’re more like a hungry brother-in-law who moves in to “get back on his feet” and then invites 200 of his best friends to eat you out of house and home.
Like that hard to evict relative, once lace bugs move into your garden they’re not interested in leaving.
Lace bugs (family Tingidae) are hungry little critters, and the spend their brief lives devouring your plants. They feed on plants by sucking up the sap from leaves, similar to thrips and mites. These bugs can cause a lot of damage, leaving only the dried-out skeleton of the leaf behind.
There are over a hundred species of lace bug in North America. Each species is specific to a host plant. In many cases, lace bugs can live out almost their entire life cycle on a single plant, sometimes even on a single leaf of a plant.
Leptodictya tabida feeds on sugarcane, while Stephanitis pyrioides feeds on azaleas. Corythucha cydoniae makes a meal out of hawthorn and Stephanitis takeyai makes a meal out of Japanese andromeda.
Lace bugs are tiny – they rarely grow over 1/8-inch in length, so they can be difficult to spot. They primarily feed on trees and shrubs, spending the majority of their time on the underside of leaves.
Lace bug damage is unlikely to kill your trees, but these pests can ruin a smaller plant’s appearance as long as they’re present.
While each plant species attracts a different type of lace bug, these different species of bug all look similar. The species difference is primarily shown in what the insect can eat. Hawthorn lace bugs can’t survive on azaleas, and ornamental grass-eating lace bugs can’t suddenly switch to hackberry plants.
Young lace bugs are dark-colored, wingless creatures. Their bodies are tiny, you won’t notice them unless you’re looking for them – and even then it can be a challenge. If you examine one up close, you’ll see a miniature, flat-bodied bug with tiny spikes poking up from his body in all directions.
Nymphs hatch from eggs laid on the underside of the host plant’s leaves. After hatching, the nymphs feed on the leaves and grow steadily for 3-4 weeks. As they grow, the nymphs shed their skin, leaving it clinging to the host leaf like a fragile bit of ash.
After five instars (growth spurts), the nymphs are adults. Adult lace bugs have wings. They quickly mate and lay eggs on the underside of an attractive leaf. The whole life cycle takes a little over a month to complete. Depending on the length of your growing season, your plants could host 2-4 generations of this pest within one year.
Like the nymphs, adults feed on the leaves of their host plants. Since the whole life cycle of these bugs can be lived out on one or two leaves of a plant, they often cause the entire leaf to wither away.
Adults from the last generation before winter will hide in bark crevices or under leaf piles to wait for spring. Lace bugs that feed on evergreens may actually spend the winter on the evergreen leaves. In the spring, the adults return to feast on the newly unfurled leaves, lay eggs, and begin a new season of life.
Recognizing Lace Bug Damage
When lace bugs are feeding on your plants, they leave a few telltale signs behind. Lace bug damage is similar to spider mite or thrip damage on the top of the leaf, but flip the leaf over, and you’ll see the full story.
On the upper side of the leaf, lace bugs leave a pattern of yellow or white mottled spots on the leaves. This is because the insects suck out the juice of the leaf from underneath, causing patches of dryness on top.
Under the leaf, you’ll see more telling signs of lace bug feeding. The underside of affected leaves is messy with shed skins and cast-off egg scabs. You may even see the greedy insects themselves.
What Should I Do about Lace Bugs?
If you’ve discovered lace bugs making a menace of themselves in the garden, you have a lot of options available to you. Because they are an annoyance more than a danger, your response to them can be as intense as you want it to be.
1. Ignore Them
You can ignore lace bugs. Like that too-familiar relative, they aren’t malicious, just a general nuisance. They’ll damage the overall appearance of your plants a bit, but they won’t kill off the plant.
Since these insects are host specific, they can’t spread throughout the garden either. If you have lace bugs on your azaleas, they’ll stay on your azaleas.
Many gardeners chose to ignore them. With so many other pests in the garden, it’s hard to get worked up about an annoying little bug that won’t destroy your plants. For other gardeners, the visual damage lace bugs do to the garden is worth a little retaliation.
2. Water Spray
Lace bug nymphs are wingless, so if you take a high-pressure hose and spray the undersides of the leaves with water. The water will knock the nymphs to the ground, and since they can’t fly, the bugs can’t get back to their plants.
If you’re using water spray to get rid of lace bug nymphs, spray the afflicted plant once a week to keep the nymphs at bay.
3. Neem Oil & Insecticidal Soap
You can add a few drops of neem oil to a batch of insecticidal soap and spray the underside of the leaves weekly to kill both the adults and the nymphs. Insecticidal soap is a helpful tool in keeping lace bugs at bay.
If you’re managing this insect on a flowering plant, avoid spraying neem-insecticidal soap while the plant is in flower. It can damage pollinators as well as lace bugs so keep your beneficial insects safe while battling the less than helpful bugs.
4. Predator Insects
Lace bugs have a lot of natural predators. If you’re looking for a natural way to defeat these invading insects, bring in reinforcements. Assassin bugs, lacewings, jumping spiders, ladybugs, and parasitic wasps are all-natural predators of these insects.
Introducing natural predators into your garden can help control pests like lace bugs, but be careful. Sometimes introduced species don’t integrate into the environment as they should.
5. Organic Pesticides
Lace bugs rarely need the “big guns” of conventional pesticides. They’re easy to deal with in low-impact ways. But if your lace bug infestation is out of control, pesticides can be a big help. Organic pesticides are a relatively gentle way to exterminate an out-of-control lace bug problem.
Try a spray that contains pyrethrin, like this one made by Bonide, on the underside of the leaves. Or try one of the many varieties of horticultural oils on the market. Both of these need to be applied every two weeks to ensure you kill off all life stages of the pest.
6. Conventional Pesticides
There are rare situations when the presence of this pest warrants the use of powerful chemical pesticides. Don’t make the mistake of going overboard in your battle against lace bugs and damaging the beneficial insects in your garden as well.
Remember that the chemical pesticides that kill off lace bugs can decimate the bees, butterflies, ladybugs, and other beneficial critters that help your garden thrive.
If you choose to use them, use them with care. Only apply them when the plant and its neighbors are not in flower. Use the minimum application to control your problem and then switch to less destructive means.
If you’re going to use chemical pesticides, cyfluthrin and permethrin work well against lace bugs. Apply them to the underside of the leaves where the bugs congregate. It’s best to apply chemical pesticides at night to minimize the damage pesticides do to pollinators, kids, and pets.
When using chemical pesticides, be especially cautious about neighborhood pets. Permethrin is highly toxic to cats and some varieties of birds. Cyfluthrin is extremely toxic to bees, but less dangerous than permethrin to household pets. Use pesticides with care and remember that this pest can often be easily controlled with less aggressive methods.