440 Invasive Stink Bugs and Related Species (Pentatomoidea)
cases, insecticides are applied in combination with preplanting and postplanting herbicides used to eliminate
weeds and also in combination with fungicides primarily used to control soybean rust (Phakopsora spp.)
(Bueno et al. 2015). The most common insecticides used to control Piezodorus guildinii are neonicotinoids
combined with pyrethroids (Baur et al. 2010). In Brazil, Farias et al. (2006) reported greater than 80% con-
trol with thiamethoxam + lamda-cyhalothrin at the rates of 21.1+15.9 and 28.2+21.2 g of active ingredient/
hectare. Similar results were reported in Argentina for several species of stink bugs on soybean (Gamundi et
al. 2007). Other insecticides such as acephate and endosulfan, commonly used in the past, have been aban-
doned. Stadler et al. (2006) in Argentina reported resistant population of P. guildinii to endosulfan.
8.8 Future Outlook
Stink bugs in general are becoming a growing concern worldwide as pests. The following factors have
been identified to explain their success: they are highly polyphagous; a reduction in insecticide applica-
tions in cotton for boll weevil control, which had secondarily helped suppress stink bug populations;
development of species-specific insecticides for heliothine control in cotton; lack of transgenic products
to control insects with piercing-sucking mode of feeding; greater ability to survive under unfavorable
conditions; and innate ability to adapt easily to new environments. Additionally, stink bugs are taking
advantage of rising temperatures worldwide, new cultivation systems (no tillage), early soybean produc-
tion systems, multiple cropping systems, and increased international trade of agricultural commodities
among countries (Panizzi 2015). For Piezodorus guildinii, in particular, these and other factors, such as
interspecific competition (Tuelher et al. 2016), surely are favoring the recent growth in its populations in
several areas of the Neotropical Region and the southern United States.
Through the years, several studies have indicated that Piezodorus guildinii is the most damaging
among the many species of pentatomids known to colonize soybean in the Americas (Vicentini and
Jimenez 1977, Panizzi et al. 1979, Sosa-Gómez and Moscardi 1995, Corrêa-Ferreira and Azevedo 2002,
Depieri and Panizzi 2011, Tuelher et al. 2016). Despite these many studies, there still is need of detailed
work to better explain the feeding and resulting damage of P. guildinii to soybean. Worthy of note is
the recently published study conducted by Lucini et al. (2016) on electronically monitoring the feeding
behavior of P. guildinii on soybean using the EPG (Electrical Penetration Graph). They found that adult
bugs use the cell rupture strategy to feed from the seed endosperm in the soybean pod and switch to
salivary sheath feeding for xylem in leaves and stems. These feeding behaviors explain symptoms of
damage to soybean. Moreover, the elucidation of the specific feeding sites opens up opportunities to
develop transgenic soybean varieties expressing toxins or blocking proteins that might inhibit the action
of the salivary enzymes in these sites to avoid or mitigate P. guildinii damage.
In conclusion, considering the growing importance of Piezodorus guildinii as a pest of soybean in the
Americas, additional field and laboratory studies are needed to advance our knowledge about this insect
to help design more effective management programs to mitigate its impact as a pest.
8.9 Acknowledgments
We thank J. E. McPherson (Department of Zoology, Southern Illinois University, Carbondale) for his
efforts in the final editing of this chapter, and J. J. da Silva (Embrapa Soja, Brazil) and Ted C. MacRae
(Monsanto, Chesterfield, Missouri) for the images of Piezodorus guildinii used in this chapter. We also
thank Tiago Lucini (Embrapa Trigo, Brazil) for help in tracking down some obscure references.
8.10 References Cited
Ahmad, I. 1995. A review of pentatomine legume bug genus Piezodorus Fieber (Hemiptera: Pentatomidae;
Pentatominae) with its cladistic analysis. Proceedings of the Pakistan Congress of Zoology 15:
329–358.