LACEBUG – an underlying problem
By Bailey Walten 1993 Newsletter
Lacebugs are among our most common plant pests in the landscape. Named for the ornately beautiful lacelike wings and lateral thoracic projections that adorn the adult insects, these bugs inflict some of the most obvious damage to our valuable trees and shrubs. Over two hundred species have been identified in North America and the majority are host specific when it comes to their culinary preferences. Of particular concern are those that attack broad-leaved evergreens such as azalea, rhododendron, laurel, cotoneaster, and pyracantha. Other species target deciduous plants like oak, sycamore, hawthorn, cherry, and mountain ash. /depending on the variety, they over-winter as adults or as eggs laid in or on the foliage of the host plant. Feeding begins in May after the tiny spiny nymphs hatch and continues through summer and into early fall with two or generations per year. Nymphs and adults feed on the underside of the leaves by piercing the epidermis and sucking plant juices and cell contents. The resultant flecking and eventual bleached appearance of the foliage resembles spider mite injury but is easily distinguished because lacebugs excrete characteristic shiny dark fecal spots that adhere to the leaf surface. With continued feeding, photosynthetic leaf function is greatly diminished, debilitating the entire plant and making it more susceptible to drought, disease, etc. At minimum, the aesthetic appearance of the foliage is ruined.
These small insects (about _ inch long) were particularly numerous this past season and we noticed widespread damage throughout our region; even into October when frost finally curtailed their activity. Many azaleas and andromedas, especially those in sunny locations, showed a lot of damage and by fall were more white than green. Experience has shown us that it is essential to begin treating by late May and make follow-up applications at timely intervals to insure control. Many products are labeled for their control. We have found that an application of Merit in late May – early June is most effective to obtain extended controls for the season. Additional sprays may be required as lacebug can remain active well into October!