Adult on Underside of Leaf
The Meerkerk Garden Staff recently observed an outbreak of lace bug at the garden. This significant pest of Rhododendrons and Azaleas becomes active in May. As the insect feeds on the underside of the leaves, the upper side of the leaves become yellow and stippled. The business end of things happens on the underside of the leaves where the insect feeds and lays its eggs in dark brown tar-like excrement.
The eggs and nymph stages are protected by the tar-like substance making it difficult to see the extent of the infestation. Infestation is worse in on water-stressed plants and on those exposed to the sun.
Lace bug has been a major problem on Rhododendron and Azalea on the mainland for some time where control has proved difficult, especially in larger landscapes.
Lace Bug Damage to Rhododendron Leaf
Adults and Nymphs on Underside of Leaf
For more information on recognizing and controlling this pest, visit WSU Hortsense
or contact the WSU Extension office in Island County