Our last couple of hot, dry summers have given rise to an often overlooked, but damaging pest on Pieris Andromeda shrubs. These plants, like most types of azalea (also a target for lace bugs), prefer a partially shaded environment, away from hot afternoon sun. When exposed to excessive heat and sunlight, they become prone to lace bug infestation.
These small, winged “true bugs” feed on the underside of the leaves in summer and fall, sucking out chlorophyll and leaving a stippling effect on the upper side of the leaves. If you have noticed this on your Andromeda, take a look at the bottom of the leaves. You may see dark “tar spots” there which are the fecal matter of the bug, stuck to the leaf along with adult and nymph-stage insects.
Although lace bug feeding is rarely fatal to a plant, the damage can cause general lack of vigor, yellowing and in some extreme instances, leaf drop. Two well-timed insecticide treatments in late spring and summer will effectively disrupt their life cycle and allow the plant to recover.
If you are already enjoying the benefits of our Yardguard tree and shrub program and have spring and summer visits as part of that, we will be targeting lace bug automatically for you. If we are not making visits to your landscape in late spring and summer, and you have lace bug susceptible plants (Andromeda, rhododendron or azalea), you may want to consider adding those treatments as well.
Feel free to give us a call anytime if you have questions or would like to discuss ordering treatments.
Senior tree and shrub technician
360 250 6346