Treatment Plans
Eliminate lace bugs
Why are your leaves losing color, and how can you stop these small insects?
The problem
Lace bugs, also called tingids and known in French as “tigres”, are small insects in the family Tingidae. Barely 3 to 4 mm (about 0.12–0.16 in) long, they are distinguished by transparent, lace-like wings. They cause your leaves to lose color. Adults and larvae live and feed beneath leaves, using their mouthparts to pierce plant cells and suck out their contents.
- Cause yellow or silvery discoloration on upper leaf surfaces where cells have been emptied.
- Leave small shiny black dots (droppings) beneath leaves.
- Severe infestations reduce photosynthesis, weakening the plant and potentially causing premature leaf drop.
They often concentrate beneath leaves, making them difficult to spot initially.
Their life cycle
The complete life cycle, from egg to adult, can last 4 to 6 weeks in favorable conditions. Stable indoor temperatures allow successive, overlapping generations, making infestation persistent unless treated thoroughly.
| Stage | Estimated duration | Detail |
|---|---|---|
| Egg laying | A few days | Females lay black eggs, often in groups, along veins beneath leaves. |
| Nymphs (larvae) | 2–3 weeks | Often gray or black and spiny, they pass through 5 stages before adulthood and feed actively. |
| Adults | Several weeks | Winged adults continue feeding and reproduce rapidly, starting a new cycle. |
The simultaneous presence of eggs, nymphs and adults explains why a single treatment is rarely enough.
What to do now
- Isolate the infested plant immediately to prevent lace bugs spreading to other plants.
- Shower foliage thoroughly, concentrating on leaf undersides, with a strong stream of water to dislodge as many adults and larvae as possible.
- Prepare a soft soap solution. Dilute approximately 75 mL (5 US tablespoons) of liquid soft soap in 1 liter (about 1.06 US qt) of lukewarm water.
- Spray generously over the whole plant, thoroughly covering the underside of every leaf. Soft soap works on contact by suffocating insects.
- Repeat every 4 to 7 days for at least 3 weeks. This targets newly hatched larvae and completely breaks the reproductive cycle.
Prevention
- Carefully inspect leaf undersides on every new plant before bringing it home.
- Check plants once a week for early signs of infestation.
- Regularly wipe leaf dust away with a damp cloth to disturb potential pests.
Common problems
- Lace bug (tingid) · A small, flat insect with lace-like wings.
FAQ
Are lace bugs dangerous to people or animals?
No. Lace bugs are harmless to people and pets. They feed exclusively on plant sap.
How can I distinguish lace bug damage from spider mite damage?
Both cause stippled discoloration. The key difference is beneath leaves: lace bugs leave **shiny black dots** (droppings), while spider mites spin **very fine webs**. Lace bug damage is also often more localized initially.
Where do these bugs come from?
Most often, they arrive on a new infested plant. They may also enter through open windows during local summer conditions, particularly near infested trees or shrubs such as plane, oak or rhododendron.
Will soft soap damage my plant?
At the correct concentration (about 75 mL (5 US tablespoons) per 1 L (about 1.06 US qt) of water), soft soap is safe for the vast majority of plants. However, always test on one leaf 24 hours before treating the whole plant. Avoid applying in full sun to prevent leaf burn.
Why must treatment be repeated several times?
Soft soap mainly kills larvae and adults on contact. **Eggs are more resistant** and may hatch after treatment. Repeating weekly for 3 to 4 weeks kills new generations before they reproduce.
Will damaged leaves turn green again?
No. Areas discolored by lace bug feeding are permanently damaged because plant cells have been destroyed. Successful treatment will, however, allow new healthy, vigorous leaves to grow.