Halyomorpha halys (Stål) 277
Konopka et al. (2017) recently investigated the question of potential coexistence using T. japonicus and
Anastatus bifasciatus. They found T. japonicus to be a superior egg guarding and more aggressiveness
and A. bifasciatus to be more successful at developing from multiparasitized eggs. Their finding suggest
that at least these two parasitoids could complement each other in terms of H. halys biological control.
4.6.5 Chemical Control
Chemical control is a critical tool for managing Halyomorpha halys as programs that lacked effective
insecticides for this bug led to devastating levels of injury in susceptible crops such as tree fruit during
the 2010 outbreak in the mid-Atlantic region (Leskey et al. 2012b,c). However, the materials identi-
fied as being effective against it include broad-spectrum materials, primarily a number of pyrethroids,
neonicotinoids, and carbamates (Nielsen et al. 2008b, Leskey et al. 2012b, Lee et al. 2013a, Kuhar
and Kamminga 2017). Among some of the most effective materials, such as bifenthrin, dinotefuran,
clothianidin and permethrin, residual activity is short, often less than 3 days in apple and peach sys-
tems (Leskey et al. 2013). Moreover, when monitoring tools were unavailable, growers responded with
increased insecticide applications; in some cases, these increased four-fold higher than were applied
previously before the outbreak of this bug (Leskey et al. 2012b). Thus, the use of decision-based tools for
timing insecticide applications is critical not only in terms of establishing the best times to spray but also
to reduce the number of applications.
Recently, several tools have emerged to improve the efficacy of management efforts using insecticides
and to reduce overall inputs (Leskey et al. 2012d, 2015a,b; Blaauw et al. 2014; Lee 2015). First, traps
baited with the aggregation pheromone and synergist mentioned above for Halyomorpha halys were
used to trigger insecticide applications in apple orchards. When traps reached a cumulative threshold
of 10 adults, this triggered an alternate-row-middle spray application and a second application 7 days
later. This approach resulted in statistically identical levels of injury at harvest and a 40% reduction in
spray applications compared with weekly spray applications. A second approach based on a border spray
regime has been evaluated in peach orchards. In this case, insecticides applied against this bug were
applied only to perimeter trees and the first full row of the block. Compared with frequent full-block
applications, this IPM-CPR (crop perimeter restructuring) resulted in significant reductions in insecti-
cide use and significantly less injury from H. halys (Blaauw et al. 2014).
Halyomorpha halys has the potential to be managed with behaviorally based approaches. One such
approach is termed “attract and kill” and relies on olfactory stimuli to attract and retain mobile life stages
to a limited geographic area where they can be killed, limiting the amount of, and the area requiring,
insecticide sprays. In this case, the aggregation pheromone and synergist (Khrimian et al. 2014, Weber
et al. 2014) have been used to attract and aggregate the nymphs and adults in border row apple trees
(Morrison et al. 2015). Three important components of any “attract and kill” strategy appear to have
been met based on the results to date. First, adults and nymphs must be attracted and aggregated to a
geographically limited area. Using increasing doses of the pheromone and synergist with baited traps
and apple trees Morrison et al. (2015) demonstrated that this bug will aggregate in an area of less than
2.5 m radius around the stimulus source regardless of dose. Second, target insects must be retained long
enough to be killed. With this bug, when the pheromone and synergist (mentioned above) are deployed
in association with a host plant (i.e., an apple tree), adults will remain for >20h compared with non-host
substrates. Finally, an effective killing agent must be in place. With this bug, efficacious insecticides
were demonstrated to provide season-long mortality in “attract and kill” apple trees located at the border
of orchard blocks. This approach appears to be promising and likely will be evaluated in other cropping
systems.
Another system to kill Halyomorpha halys nymphs and adults once they enter pheromone traps
may be the use of insectide treated netting. Kuhar et al. (2017) using deltramethrin treated nets against
H. halys in the laboratory showed that exposure to the nets for 10 seconds was enough to cause >90% and
40% mortality of nymphs and adults, respectively. They also showed that when the treated netting was
placed inside a stink bug trap it provided kill rates similar or better than a standard diclorvos kill strip.
RNA interference or the use of double-stranded RNA (dsRNA)-mediated gene silencing is another poten-
tial option for the management of Halyomorpha halys. The technique uses gene regulatory mechanisms