258 Invasive Stink Bugs and Related Species (Pentatomoidea)
emergence from mid-May to early June. They also found that emerging adults did not respond to the
pheromone-baited traps suggesting that a dispersal flight may be necessary before they respond to the
pheromone. Current laboratory studies, reproductive activity in the field, and a predictive population
model in the United States strongly point towards the diapause cue for H. halys being photoperiod-driven
with a critical photoperiod of 13.5h (Anne L. Nielsen, unpublished data).
The impact of abiotic conditions on population dynamics of Halyomorpha halys during the active
growing season and the overwintering period is poorly understood. In the United States, populations
have fluctuated dramatically from year to year in areas in the mid-Atlantic with well-established popula-
tions since 2010, but key factors promoting or reducing survivorship as well as those influencing range
expansion remain unknown.
4.4.5 Host Plants
Halyomorpha halys is a highly polyphagous, primarily arboreal species (Hoffman 1931, Hoebeke and
Carter 2003, Bernon 2004, Nielsen and Hamilton 2009b), having been collected from numerous plant
species in Asia, Europe, and North America. These collection records include both wild hosts and cul-
tivated species and, often, are documented with notes on the presence of eggs, nymphs, and/or adults,
and inclusion of feeding records (Hoebeke and Carter 2003, Bakken et al. 2015). In its native range (i.e.,
Asia), it has been reported to feed on at least 106 host plants such the Princess tree, Chinese arborvitae,
Chinese milk vetch, mulberry, elm, willow, and Chinese scholar tree (Wang and Wang 1988, Bae et al.
2009, Lee et al. 2009). Agricultural hosts include apple, citrus, peach, pear, sweet persimmon, and Yuzu
(Qin 1990, Fengjie et al. 1997, Funayama 2003, Kang et al. 2003, Lee et al. 2007). It also feeds on soy-
bean, sorghum, corn, and various vegetables (Oda et al. 1980, Kawada and Kitamura 1983a, Fukuoka et
al. 2002, Kang et al. 2003, Bae et al. 2009).
Outside of Asia, several authors have documented that Halyomorpha halys adults and/or nymphs can feed
on a much wider range of hosts. In Europe, H. halys has been found for the first time feeding on rice grown
in northern Italy (Lupi 2017). In North America, this bug has been collected from honeysuckle, walnut,
shadbush, butterfly-bush, paulownia, persimmon and maple in the spring in Allenton, PA (Hoebeke and
Carter 2003). Nymphs also have been collected on many of the same hosts and from basswood and catalpa in
the same area in July. Nielsen and Hamilton (2009b) observed adults and nymphs on several cultivated fruit
species and on rugosa rose, white ash, high bush cranberry, Blackhaw cranberry, Russian olive and Siberian
pea shrub. Hedstrom et al. (2014) report feeding by this bug on hazelnuts grown in New Jersey. H. halys has
been documented as feeding on eggplant, lima beans, okra, peppers, sweet corn, and tomatoes (Leskey et
al. 2012a, Rice et. al. 2014). Zobel et al. (2016) evaluated bell pepper, eggplant, green beans, okra, pepper,
sweet corn, and tomato in terms of seasonal densities, host suitability, and feeding injury. They found that
overwintering adults and F1 juveniles were present during the growing season, and that H. halys preferred
plants with fruiting structures, exhibited higher numbers, and could reproduce on crops with extended fruit-
ing periods. Significantly higher populations were found on sweet corn, okra and bell pepper compared
to eggplant, green beans, and tomato. Phillips et al. (2016) examined seasonal abundance and phenology
of H. halys in different pepper varieties (sweet bell, hot chili and sweet banana) in Delaware, Maryland,
New Jersey and Virginia. They found no differences in abundance of H. halys life stages or damage caused
between varieties. Bakken et al. (2015) surveyed wild hosts in North Carolina and Virginia and observed
nymphs and adults feeding on over 50 different species. Additional known North American host species are
presented in Table 4.1. The utilization of ornamental hosts in commercial hosts also has been examined
(Bergman 2015, Bergman et al. 2016). These authors showed that of 131 species sampled, 88 were hosts,
angiosperms supported larger H. halys populations, and Asian cultivars supported fewer individuals than
non-Asian cultivars. These results were most apparent in Acer, Ulmus and Pyrus species.
4.4.6 Movement between Host Plants
Adults and nymphs of Halyomorpha halys are highly mobile and readily move between hosts plants
during the growing season (Nielsen and Hamilton 2009b, Venugopal et al. 2015a,b). In the laboratory,
the vertical and horizontal dispersal capacities of nymphs were shown to vary between instars with third