Plants in Your Garden Looking Stressed?
It’s been a challenging season so far, that’s for sure! Temperature extremes and dry spells can wreak havoc on a gardener’s nerves AND their plants!
If you are noticing plants (particularly Asters) looking yellowed or stressed, it might be worth taking a second look. What might at first glance appear to be general summer stress may in fact be lacebugs. You may see them on asters. But don’t worry, we’ve got you covered!
What Is Lacebug?
Lacebugs are tiny insects that suck sap from plants. There are many species of lacebugs, each having their own preferred type of host plant. Chrysanthemum lacebugs (a native species) affect plants in the aster family. They also can affect late season flowering perennials such as goldenrods and black-eyed susans.
There are usually two generations of lacebug each season. Adults that have over-wintered begin laying eggs in spring, with nymphs appearing in early May. Adults are abundant by June. The second generation is usually late summer or fall. Second generation adults over-winter in the soil. When spring arrives, they lay eggs in newly expanded leaves. Some species also over-winter as eggs.
Cultural issues such as drought allow lacebug populations to soar, as they take advantage of a weakened plant. Populations can vary from year to year, so you may see more one year than another.
Lacebug/Lacebug Damage ID
The adults and the nymphs feed on the foliage, usually causing yellow stippling and black dots. Extensive damage may cause foliage to die off. The good news is, they do not normally affect the overall health and survival of a plant.
You may start seeing the nymphs in early May. Foliar damage will start appearing at that time. Once foliage is damaged, it remains damaged and cannot heal. Cutting back heavily affected foliage can help reduce populations.
The adult lacebugs are 1/8″ – 1/3″ long. Turn over a leaf that has yellowing and stippling and look on the underside for them. Their lacy wings will be visible. Nymphs are dark and do not have wings.
When lacebug nymphs molt their exoskeletons, their cast skins remain attached to the foliage of the plant. Adults and nymphs also leave very small, dark droppings on the undersides of leaves.
Controlling Lacebug
Use an IPM (Integrated Pest Management) Approach
Step one for any insect control program is to positively ID the insect. Insecticides can be used but will potentially harm other beneficial insects including predators that may control the lacebug infestation. There are natural predators of lacebug such as lady bugs and assassin bug. In a diverse landscape, they will come. We do not recommend purchasing predator insects.
Lacebugs generally do not affect the overall health of perennial plants, and the best option in most cases is to tolerate and ignore them.
Control Methods
Mechanical control -A sharp blast from the hose on the upper and lower surface of the leaves of the plants can help knock off the adults and reduce population.
TL/DR
Look for these 3 things to check for Lacebug:
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- Yellowed and stippled leaves
- Winged adults on the underside of the leaves
- Black dots or droppings on the undersides of the leaves.
What to do about Lacebug:
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- Perennial plants will not die.
- No need to spray – natural predators may come.
- At the end of the season cut back the affected plants and dispose of the trimmings so the lacebug does not overwinter in the garden.
More Information
The following website has more detailed information, photos, and insights:
https://extension.umn.edu/yard-and-garden-insects/lace-bugs
