270 Invasive Stink Bugs and Related Species (Pentatomoidea)
nymphs and adults and resulting damage in pear and apple orchards in Allentown, Pennsylvania, and
Pittstown, New Jersey. They found that nymphs occurred at low densities throughout the season in
apples, and that peak densities in pear occurred in early July and mid-August when pit hardening and
swelling occurred, respectively. In addition, they found that more than 25% of the fruit in each crop was
damaged by H. halys feeding. In apples, damage was characterized by discoloration of the outer surface
and discolored dots with depressions due to the insertion of the bug’s stylets into the fruit (Nielsen and
Hamilton 2009b, Brown and Short 2010). Similar damage occurs in pears and peaches (Nielsen and
Hamilton 2009b).
Populations of Halyomorpha halys continued to increase and spread throughout the mid-Atlantic
United States with few reports of agricultural damage occurring. However, in 2008 and 2009, damage to
apples and peaches by H. halys was observed for the first time, but the bug was not considered a widely
distributed pest geographically until 2010 (Leskey and Hamilton 2010a, Leskey and Nielsen 2018)
(Figure 4.1E). During the 2010 season, feeding by this bug in apples alone in the mid-Atlantic United
States was estimated to have caused a loss of $37 million in apples and >90% losses by some growers in
peach orchards (Leskey and Hamilton 2010b, Anonymous 2011). Feeding, at least in apples, appears to
be related spatially to where fruit occurs in the tree canopy and within an orchard. Joseph et al. (2014),
using a zero-inflated negative binomial model, found that apples in the upper canopy of border trees
were more likely to be damaged. Acebes-Dori et al. (2016b) examined the injury caused to apples and
peaches at harvest due to feeding by nymphs. Their study showed that feeding by young nymphs early
in the season resulted in the least amount of damage to each crop. Feeding by adults on apples late in the
season caused the most damage. However, feeding by adults on peaches early in the season resulted in
the greatest amount of damage.
Since 2010, Halyomorpha halys has been observed damaging several vegetable crops including beans,
eggplant, peppers, okra, sweet corn, and tomatoes (Leskey et al. 2012a, Rice et al. 2014). In beans and
okra, damage appears as scarred or faded depressions. In tomatoes and peppers, its feeding causes white
or yellow surface spotting with underlying tissue damage. Feeding in sweet corn causes discolored and
sunken kernels.
In addition to peach, apple, and pear, Halyomorpha halys also feeds on blackberries, blueberries, rasp-
berries, and wine grapes (Leskey and Hamilton 2010b, Leskey et al. 2012a, Rice et al. 2014). In blueber-
ries, Wiman et al. (2015) found that feeding in early and late ripening varieties caused discoloration and
internal damage to fruit and reduced fruit weight and soluble solids. Feeding by H. halys also has been
shown to modify the chemistry and attractiveness of the fruit (Zhou et al. 2016). In the field, feeding
caused lower levels of anthocyanin, phenolics and soluable solids (Brix). In blackberries and raspberries,
early season feeding caused death of blossoms whereas late season feeding caused discoloration and
collapse of drupes due to the bugs’ inserting their stylets between individual drupes (Basnet et al. 2014,
Rice et al. 2014). In wine grapes, H. halys adults enter vineyards in May in Virginia, lay eggs in June and
July followed by the presence of all developmental stages until September (Basnet et al. 2015). Feeding
by nymphs and adults on grape clusters causes necrosis and deformation of individual fruit (Pfieffer et
al. 2012, Rice et al. 2014). There also are concerns that the inclusion of the bugs with harvested grape
during the crush process may taint the final wine product (Tomasino et al. 2013, Mohekar et al. 2014,
2016). Mohekar et al. (2017) examined this concern and found that the release of tridecane and (E)-2-
decanal by H. halys during processing negatively affected the final quality of the wine.
Halyomorpha halys feeds on a variety of field crops including corn, cotton, hops, sorghum, soybeans,
sunflower, and wheat; however, corn and soybeans appear to be the main crops attacked thus far (Rice
et al. 2014). In corn, bug populations peak mainly during milk (R3) and dough (R4) stages of ear forma-
tion. As noted above, feeding through the husk discolors and shrinks individual kernels. There is some
evidence from Pennsylvania that feeding on the plants prior to the R1 stage may cause ear abortion.
When bugs enter soybeans field, they remain primarily in border rows during the R4 to R6 stages of
plant development and are able to feed on developing seeds through the pods (Rice et al. 2014). Late
season feeding in soybeans in border rows causes a “stay green” effect characterized by plants that
senesce later than the rest of the field. The effect makes it difficult to harvest the entire field thereby
causing yield losses. H. halys recently has invaded urban areas in Minnesota. However, a 2-year survey
of soybeans in Minnesota found no bugs despite its continued detection in urban areas (Koch and Pahs