Piezodorus guildinii ( Westwood) 437
trials at four stink bugs per meter, yield differences were not detected among the species but P. guildinii
damaged more seed. In greenhouse infestations at two stink bugs per plant, lower yields occurred in
plants infested with P. guildinii. Feeding by P. guildinii resulted in significantly more empty pods than
the other stink bug species (Corrêa-Ferreira and Azevedo 2002). P. guildinii has been shown to be more
damaging than N. viridula and Euschistus heros due to deeper stylet penetration into seeds, greater
enzymatic activity of saliva, and larger food and salivary canals (Depieri and Panizzi 2011).
8.6.2 Impact of Other Piezodorus spp.
In addition to Piezodorus guildinii, at least five species are crop pests: P. hybneri (Gmelin) (= P. rubro-
fasciatus F.) in Asia and Africa, P. lituratus (F.) in Europe and western Asia, P. oceanicus (Montrouzier)
in Australia, P. punctiventris (Dallas) in West Africa, and P. purus Stål in sub-Saharan Africa. The one-
banded stink bug, P. hybneri, is a major pest of soybean and other leguminous crops in Asia and Africa
(Ishihara 1950, Joseph 1953, Gentry 1965, Kobayashi et al. 1972, Gill 1987, Singh et al. 1989, Tengkano
et al. 1991, Higuchi 1993, Dwomoh et al. 2008, Srivastava and Srivastava 2012, Bayu and Tengkano
2014). It is difficult to control because of its frequent movement (Ishikura et al. 1955). This situation has
led to many studies on alternative management strategies in Japan (Higuchi 1993, Kikuchi et al. 1995),
Indonesia (Tengkano et al. 1991, Bayu and Tengkano 2014), and Malaysia (van den Berg et al. 1995).
Piezodorus lituratus, the gorse shield bug, a common insect in Europe and western Asia, is a pest of
soybean in Italy (Zandigiacomo 1990, 1992) and a minor pest of hazelnut in Turkey (Tuncer et al. 2014).
Blatchley (1926) reported it from Florida, but Van Duzee (1904) doubted that this species occurred in
North America. Froeschner (1988) agreed with this latter opinion. P. oceanicus, the redbanded shield bug,
is a major pest of soybean and other legume crops in Australia (Gross 1976; Evans 1985; Bailey 2007;
Brier 2007, 2010). P. punctiventris is a pest of soybean; okra, Abelmoschus esculentus (L.) Moench; and
other vegetables in Nigeria (Ezueh and Dina 1979, Akinlosotu 1983, Jackai et al. 1998). P. purus has been
implicated in transmitting a bacterial disease in cotton in southern Africa (Pearson 1934). It also has been
reported as an occasional serious nuisance in South Africa, with hordes of bugs migrating from the field and
descending upon homes, resulting in occupants having to vacate (Haines 1935, Sithole and Oelofose 2006).
8.7 Management
8.7.1 Monitoring
In North America, the most common protocol for monitoring stink bugs in soybean relies on the sweep
net (38 cm diam) that measures infestations in the upper canopy. The number of stink bugs per 100
sweeps is then recorded. Once thresholds have been met, control measures are initiated. Though alterna-
tive methods such as fumigation and ground cloth exist to sample populations, the sweep net is the most
efficient (Kogan and Pitre 1980). Stink bugs disperse in clumped patterns resulting in diverse densities
within a field (Kogan and Pitre 1980). To maintain precision, the sampling distribution should include
sampling across the entire field, which the sweep net can accomplish in a short period of time. In addi-
tion, Russin et al. (1987) demonstrated that a complex of stink bugs (Nezara viridula, Chinavia hilaris,
and Euschistus servus) preferred to feed on pods in the upper half of the plant canopy, increasing the
chance of detection by sweep net.
For Piezodorus guildinii in the United States, damaging populations in soybean will occur from
growth stage R4 to R7 (Temple et al. 2013a). Furthermore, the earlier the variety matures, the more
likely that heavier population densities will increase (Temple et al. 2013a). With limited alternative hosts
available during the summer months, populations remain concentrated in soybean fields where the bugs
are capable of quickly building to economically important levels. Thus, monitoring should begin before
R3 (pod initiation) in order to track population growth. Finally, because P. guildinii has the propensity
to develop large numbers (3 to 5 times action threshold) quickly in soybean (Temple et al. 2011), recom-
mendations are to monitor every 5 days.