- All lace bugs (family Tingidae) are plant feeders that attack many types of plants.
- Adults and nymphs prefer feeding on the undersides of leaves of deciduous trees and shrubs.
- Lace bug feeding can discolor leaves, but does not normally affect the health of woody plants.
- Pesticides can be effective in reducing lace bug numbers, but should be used only if necessary.
In Minnesota, lace bugs feed on:
- White oak
- Bur oak
- Amelanchier (juneberry/serviceberry)
How to identify lace bugs
Lace bugs are 1/8 inch to 1/3 inch long and have light colored bodies with dark colored markings.
The top of their wings, head and thorax are made up of many raised ridges. These ridges give the insect a lacelike appearance.
- On adults, the wings extend beyond the abdomen and are held flat.
- Nymphs are wingless and spiny with a flat oval shaped body. They are darker than the adults.
When lace bug nymphs molt their exoskeletons, their cast skins remain attached to the foliage of the plant.
Adults and nymphs also leave dark, varnish-like excrement on the undersides of leaves.
Life cycle of lace bugs
Lace bugs have two generations per growing season in Minnesota. They live through the winter, as adults on or near their host plants.
They can be found in bark crevices and under leaves and other debris on the ground next to these plants.
- In the spring, adults fly to plants and feed on newly-expanding leaves.
- The adults mate and lay tiny black eggs in small groups on the underside of the leaves.
- Eggs hatch into nymphs after about two weeks.
- Nymphs feed for about three to four weeks and mature into winged adults that lay additional eggs.
- This second generation feeds until late summer or fall.
- Adults from the second generation overwinter and begin the cycle anew the following spring.
Damage caused by lace bugs
Feeding damage is most noticeable in mid to late summer when populations are at their highest.
Adults and nymphs insert needle-like mouthparts into leaf tissue to create small, white or yellow spots on the leaf surface.
Heavy feeding can cause severe leaf discoloration and premature leaf drop.
Healthy, mature trees and shrubs can tolerate damage from high populations of lace bugs.
In case this happens for several consecutive years, plant growth reduces in new transplants.
Lace bug populations and the extent of damage vary from year to year.
How to protect your garden from lace bugs
Check for lace bugs on susceptible trees and shrubs, starting in late spring or early summer. Pay close attention to plants that have had a history of infestation.
Try to ignore their presence
Lace bugs generally do not affect plant health, and the best option in most cases is to tolerate their feeding. Many natural enemies, such as assassin bugs, lady beetles, green lacewings and other predators feed on lace bug eggs, nymphs and adults.
Use a high pressure water spray
A high pressure water spray from a garden hose acts like a heavy rain, knocking nymphs off of small plants. Nymphs lack wings and cannot return to plants.
Target water sprays at the undersides of the leaves where lace bugs are feeding.
When using pesticides, be sure to spray the undersides of the leaves where lace bugs are found.
Insecticidal soaps and horticultural oils are less toxic, are effective against lace bugs and have low impact on natural enemies. For good results:
The product should come in direct contact with lace bugs.
Repeat applications may be necessary.
Broad-spectrum pesticides are effective, but they will kill natural enemies. Use these pesticides carefully:
Lambda cyhalothrin and other pyrethroids (typically ending in –thrin)
DO NOT use systemic pesticides, such as imidacloprid and dinotefuran on flowering trees and shrubs as they are toxic to bees. These pesticides can move into the pollen and nectar of flowers where they can affect the bees.
Contact a licensed landscape pesticide applicator, if you need help with pesticide treatments.
CAUTION: Mention of a pesticide or use of a pesticide label is for educational purposes only. Always follow the pesticide label directions attached to the pesticide container you are using. Remember, the label is the law.
Reviewed in 2018