Corythucha salicata Gibson (Heteroptera: Tingidae)
Lace bugs are generally not a pest of poplars grown east of the Cascade Mountains, but expanded plantings of poplars for potential biofuel production in western Oregon and Washington have been attacked by these sap-feeding insects. Our objective is to alert professional integrated pest management (IPM) personnel to the potential damage lace bugs can cause in hybrid poplars grown for biofuel west of the Cascade Mountains in the Pacific Northwest (PNW).
Lace bugs are common in North America: 160 species have been identified (Hoover 2002) and over 12 species have been reported from California alone (Dreistadt et al. 2004). The western willow tingid, Corythucha salicata Gibson (Figure 1), has been a pest of apple orchards in Oregon and Washington for 80 years (Thompson and Wong 1933). The top dorsal surface of the front wings, head, and thorax of adults is membranous, thus giving a lacelike appearance, hence their common name, lace bug. Nymphs are spiny and much darker in appearance than adults. Another tingid, C. elegans, feeds on poplar and willow in both Oregon and Washington (Gninenko 2007).
Several species of Corythucha lace bugs feed on broadleaf trees. All species are rather host specific, and C. elegans and C. salicata infest poplar and willow in the PNW. Froeschner (1971) was the first to record their attack on Populus tremuloides. Lace bugs that feed on Salicaceae are known as Corythucha spp. and feed on willow, balsam poplar, bigtooth aspen, and quaking aspen (Raupp et al. 2002). Initial specimens that lead Gibson (1918) to identify Corythucha salicata as a new species came from willow. Current lace bug specimens collected from poplars in western Oregon were identified as C. salicata by Laura T. Miller, West Virginia Department of Agriculture, Charleston, West Virginia.
Western willow tingid C. salicata has been collected from Nevada (Froescher 1971), Oregon, and Washington in the US, and from British Columbia and Manitoba Canada (Thompson and Wong 1933).
Small (3–8 mm) rectangular-shaped adults overwinter in rubbish on the ground or moss on nearby trees (Thompson and Wong 1933). Feeding and mating occurs in April. After bud burst, females oviposit eggs on the underside of new leaves starting in late April and continuing into July. Heteroptera have hemimetabolous development, meaning nymphs look like miniature adults without wings (Figure 2). There is no pupal stage. Most lace bug species have five nymphal stages before the winged adult appears. Nymphs hatch in early spring and feed on the leaves in aggregations. Development from the egg to fifth instar requires about 25 days (Thompson and Wong 1933).