Life History of the Invasive Species Halyomorpha halys (Hemiptera: Pentatomidae) in Northeastern United States

Host plant use by nymphs and adults of the nonnative speciesHalyomorpha halys (Stål) (Hemiptera: Pentatomidae) was investigated proximal to the location of its introduction, Allentown, PA. The seasonality ofH. halys in the United States had not been thoroughly studied before this work. It is reported to have 300 host plants in its native range that could make control and identiÞcation of small populations difÞcult.Weekly beat sampleswere conducted beginning at petal fall (mid-April) in Pyrus spp. until the Þrst frost (mid-October) from 2005 to 2007 on a variety of ornamental trees, shrubs, and agricultural crops. Eggmasseswere Þrst observed on Paulownia tomentosaThunb. the Þrst week of June. In 2006 and 2007, Fraxinus americana L. was an important midand late season host for adults. Nymphal abundance differed seasonally.P. tomentosa supported high densities during the early season, whereas Viburnum opulus variety americanum Aiton was the preferred mid-season host, and Viburnum prunifolium L. and Rosa rugosa Thunb. had the highest densities of nymphs during the late season. Abundance of nymphswas strongly associatedwithmaturing fruit or pods. All plants surveyed supportedpopulations ofH.halys, suggesting a largehost range. In lateAugust, a large adult population peak was observed (850Ð1,000 degree days [DD]), shortly after the DD accumulation for development to imaginal eclosion, supporting hypotheses that H. halys is likely univoltine in this region. Relative tonativepentatomid species,H.halyswasby far thepredominant species collected in samples on ornamental and cultivated crops.