400 Invasive Stink Bugs and Related Species (Pentatomoidea)
southeastern United States. Stink bugs are considered major pests of corn, but there are limitations to the
effectiveness of the insecticide approach for the pest group because of crop structure interfering with effec-
tive delivery of foliar-applied active ingredients and a lack of any labelled organophosphate insecticides.
In addition to physical damage caused by stink bug feeding, these pests also transmit common plant
pathogens that further decimate cash crop value. Turner (1918) discovered that when he caged Nezara
viridula on pecan nuts, it resulted in kernel spot and black pit; both conditions are reflections of reduced
nut quality. More recent work shows that pathogens causing boll rot in cotton are physically present
on stink bug mouthparts, and the pathogens can be transmitted when feeding. For example, feeding
on developing cotton bolls can result in the loss of individual locks or the entire boll (Medrano et al.
2009a,b). Young bolls (1–2 weeks postanthesis) inoculated with these pathogens will be consumed com-
pletely by the pathogen, whereas older bolls (≈3 weeks postanthesis) likely will show only a localized
infection. N. viridula can acquire and transmit at least two boll rot pathogen species that have been
isolated from diseased cotton bolls in the Southeast. These pathogens include the bacterium Pantoea
agglomerans and the fungal pathogen Nematospora coryli (Medrano et al. 2009a). Quick field assays to
detect boll rot pathogens in bolls or stink bugs currently are not available.
7.6 Impacts on General Public
Aside from economic impacts (e.g., monitoring, insect control costs) on cultivated crops (see Section 7. 5)
directly affecting producers, Nezara viridula does not noticeably affect the general public as do some
other invasive pest pentatomids such as Halyomorpha halys (see Chapter 4).
7.7 Management
7.7.1 Monitoring Options
Stink bugs are highly aggregated in the field, which complicates scouting and monitoring. It generally is
easier to assess damage from stink bugs as opposed to estimating population density. Although a phero-
mone blend for Nezara viridula has been identified (e.g., Aldrich et al 1993), trapping for population esti-
mation is not particularly effective for this insect. Mizell and Tedders (1995) modified a pyramid trap that
makes it suitable for trapping stink bugs including N. viridula, but few captures are observed in the field.
Further, research shows that more insects will be captured if the collection reservoir is baited with phero-
mone and provisioned with a method to anesthetize or kill the captured specimens (Cottrell 2001). Trap
placement appears to be critical as Tillman et al. (2010) reported capture of N. viridula in pheromone-
baited traps increased when the traps were placed at the interface of two crops. Pheromone traps have been
used to indicate when stink bugs are dispersing into tomato fields (McPherson and McPherson 2000).
Mizell et al. (1996, 1997) reported that three to five pheromone traps on a border row in the interior of a
pecan orchard could provide useful information for making pest management decision support. However,
additional research and breakthroughs are necessary to make traps the primary means of monitoring this
pest. More recently, Endo (2016) indicated light traps could be used in Japan to predict populations of
N. viridula and aid in assessing seasonal changes in reproductive development of collected female adults.
Reliable sampling methods for estimating stink bug abundance in the field include the sweep net,
ground cloth, beat bucket, and visual counts. The sweep net is commonly used for scouting stink bugs in
row crops. Todd and Herzog (1980) describe sampling methods for use in soybean utilizing 25 sweeps
from a single row, and Reay-Jones (2010) used a sweep net to estimate abundance in wheat. Todd (1981),
using a beat sheet to estimate stink bug density, indicated that control would be required when stink bug
population exceeded 1.1 or 3.3 bugs per row meter depending on soybean maturity. Sane et al. (1999)
compared sampling efficiency among the sweep net, ground cloth, vertical beat sheet, and absolute
sampling methods for all stink bug species in soybean. Reay-Jones et al. (2009) compared the sweep net
and beat cloth for sampling stink bugs in cotton and found evidence that a drop cloth biases the sample
toward nymphs whereas the sweep net creates biases toward adults. A beat bucket sampling technique