How to Control Lace Bugs

If you suspect a lace bug problem in your flower garden, get out your magnifying lens, because these garden pests are only about 1/8 inch long. Under magnification, you can see where these bugs get their name. Their transparent wings form a lacy shield over their square-shaped bodies.

In the flower garden, the most likely victims of lace bugs are azalea bushes, particularly those growing in sunny locations. The adult bugs and their larvae feed on azaleas and other flowering plants and shrubs throughout the growing season, using their sharp mouthparts to pierce plant foliage and suck the juices from leaves. Damage from lace bugs is primarily cosmetic and does not seriously harm plants. Typical signs of damage include:

• Yellow or white stippling on leaves
• Evidence of leaf curl
• Browning of leaves during active growth
• Premature leaf drop

4 Ways to Get Rid of Lace Bugs

These tiny insects do not harm humans and typically are not a problem for indoor plants. In many cases, they can simply be ignored, but you may want to treat for heavy infestations, especially when this becomes a recurring problem on specific plants. With most mild infestations, experts encourage gardeners to tolerate these insects because they do not typically cause significant harm, and control efforts often are detrimental to beneficial insects.

Water Spray

The simplest solution for getting rid of lace bugs is to spray them off of the foliage with a garden hose and sprayer. This washes the nymphs from the leaves, and they fall to the ground and cannot return to the plant. This approach is most effective early in the insects' growing cycle, when most of those present are nymphs. Repeating the treatment periodically throughout the season helps to suppress infestations.

Organic Pesticide Sprays

Despite their imposing shields, lace bugs are susceptible to most organic pesticide sprays. The trick is to apply the sprays thoroughly to the undersides of leaves, where lace bugs feed and reproduce. Use these sprays to kill active lace bug adult and larvae populations:

• Light horticultural oil
• Insect soap
• Neem

Biological Controls

Many predators feed on lace bugs, reducing the need to spray insecticides on your plants. Natural lace bug enemies include:

• Assassin bugs
• Lacewings
• Ladybugs
• Pirate bugs
• Predatory mites
• Spiders

If you want to provide a beneficial bug-friendly habitat to attract these natural predators, do not use insecticide sprays. Insecticides not only kill beneficial insects, but they also eliminate the food source of beneficial bugs, forcing them to seek greener pastures.

Conventional Pesticide

If lace bug swarms are turning your flowering oasis into a withered graveyard, it might be time to break out some conventional chemical pesticides as a last resort. A benefit of these broad-spectrum sprays is their residual effect, helping to kill multiple generations of lace bugs.

What Causes Lace Bugs?

Lace bugs appear on vulnerable plants typically in late spring and into early summer. The lace bug life cycle begins when the adult female inserts eggs into the leaves of host plants, typically on the underside and near the midrib of the leaf. Nymphs hatch from the eggs in about two weeks and begin feeding on the leaves. The nymphs mature into adult lace bugs in three to four weeks.

You can identify lace bugs by simply inspecting the undersides of leaves. Adults and developed nymphs (which are wingless and have dark spines on their bodies) are readily visible on leaf surfaces, if you look closely. Another common sign of lace bugs is the presence of shiny brown to black spots on the leaf surface. These are coverings of excrement that female lace bugs place over their eggs for protection (most, but not all, species do this). The spots remain on leaves after the eggs hatch and the nymphs mature into adults.

How to Prevent Lace Bugs

As with all plants, those under stress make the tastiest meal for insect pests. Ensure your plants can shrug off minor lace bug attacks by keeping them healthy. You may as well hang up a neon “Dine Here” sign if you allow your azalea to bake in full sun. Dry soil and an absence of mulch also create conditions that pique the interest of lace bugs. Dappled shade or morning sun, regular irrigation, and a 3-inch layer of organic mulch help to keep plants vigorous and pest-free.

If lace bugs become a perennial problem for specific plant types or plants in certain locations, consider replacing the plants with less susceptible species or moving the plants to a location that is less favorable to lace bugs. If your azaleas are frequently attacked and they get a lot of sun, try moving them to a part-sun location, provided they get enough sun to thrive. There are also azalea cultivars that boast resistance to lace bugs as well as other shrubs known to be resistant, such as hydrangea and daphne.

Lace bugs can overwinter on evergreen plants and emerge in the spring. Eggs survive on leaves, while adults survive under bark, leaf, or mulch debris, or other cover for protection. In climates with mild winters, lace bugs can overwinter as eggs, nymphs, and adults.

You can help eliminate overwintering bugs by raking up dropped leaves and other debris from beneath susceptible plants. Some experts recommend leaving the soil beneath plants bare (free of mulch) for mid-winter, then mulching (as needed) before spring, using fresh mulch. Be sure the new mulch does not contain leaves from the same family of plants, which may attract lace bugs in the future.