436 Invasive Stink Bugs and Related Species (Pentatomoidea)
8.6 Economic Impact
8.6.1 Feeding and Injury
Stink bug feeding on soybean pods reduces yield and quality, decreases seed weight, delays crop matu-
rity, reduces seed oil content, and reduces germination of harvested seed (Miner 1966, Duncan and
Walker 1968, Jensen and Newsom 1972, Todd and Turnipseed 1974, Todd 1976, Miller et al. 1977,
McPherson et al. 1979, Panizzi et al. 1979, Russin et al. 1987, Brier and Rogers 1991). Soybean seed with
severe stink bug injury does not have oil or meal value (Todd 1976, 1982), resulting in price dockage or
sale rejection (McPherson et al. 1994).
Stink bugs, including Piezodorus guildinii, also are capable of transmitting bacteria (some of which
are plant pathogens) to their hosts when feeding (Husseneder et al. 2017). The full impact of this trans-
mission on plant injury and the range of pathogen species involved currently is unknown for P. guildinii.
Delayed soybean maturity, defined as soybeans that retain leaves and have green stems and/or green
pods long after normal senescence (Boethel et al. 2000), is associated with stink bug injury. This syn-
drome results in delayed harvest and decreased quality of harvested soybeans. In some cases, this prob-
lem has prevented seed harvest and resulted in crop destruction. Harvesters are unable to efficiently
process green stems as they become entangled in the threshing apparatus. This decreases threshing effi-
ciency while increasing wear on machinery, reducing fuel efficiency, and limiting yields. Furthermore,
green stems and pods retain moisture, which can then be transferred to harvested grain. High moisture
will create postharvest spoilage, and producers are penalized when selling grain with high moisture
content.
Historically, in the United States, delayed maturity has been reported in response to infestations of
Nezara viridula and Euschistus servus in Arkansas, Georgia, and Louisiana (Daugherty et al. 1964,
Duncan and Walker 1968, Todd and Turnipseed 1974, Boethel et al. 2000). Boethel et al. (2000) showed
that N. viridula infestations at a density of six stink bugs per 0.3 meter of row for 7–14 d between R3 and
R5.5 growth stages resulted in delayed maturity. More recently, Vyavhare et al. (2015) demonstrated that
Piezodorus guildinii at densities of eight adults per 0.3 meter caused delayed maturity in United States
soybeans.
In Brazil, delayed maturity has been associated with Piezodorus guildinii infestations in several
reports. Panizzi et al. (1979) reported that soybeans retained leaves when P. guildinii infested soybean
during pod development and pod fill stages (R3–R6). Populations of two to five P. guildinii adults per
plant caused excessive green foliage retention when infested at the R4 stage (Costa and Link 1977),
whereas continuous infestations of six to ten P. guildinii per meter during seed development (R4–R6)
caused green foliage retention, but foliage retention did not occur in soybean infested prior to seed devel-
opment (R1–R3) (Galileo and Heinrichs 1978). Sosa-Gómez and Moscardi (1995) investigated differ-
ences in leaf retention among different stink bug species and found that P. guildinii caused greater leaf
retention than N. viridula and Euchistus heros ( F.).
In the United States, Nezara viridula and Chinavia hilaris historically were considered the most dam-
aging species in soybean compared to other species (Miner 1961, McPherson et al. 1979). However, this
has changed with the arrival of Piezodorus guildinii. Preliminary data from caged experiments indicates
P. guildinii is an aggressive soybean feeder, damaging 94% of pods, 79% of seeds, and reducing seed
weight by 78% within 72 hr (Parker 2012). However, literature currently is not available comparing
P. guildinii damage potential to N. viridula and C. hilaris.
Current action thresholds for most stink bugs in the United States range from 20 to 36 per 100 sweeps
(Greene and Davis 2015). However, because Piezodorus guildinii damages soybeans quickly, is more
tolerant of insecticides, recolonizes soybean fields faster, and appears to reproduce faster than other
stink bug species, the current threshold for P. guildinii in Louisiana is 16 insects per 100 sweeps (Ring
et al. 2015).
In South America, Piezodorus guildinii has the greatest potential to damage soybean (Vicentini and
Jimenez 1977). In Brazil, Corrêa-Ferreira and Azevedo (2002) directly compared soybean yield loss and
seed damage by P. guildinii, Nezara viridula, and Euschistus heros in the field and greenhouse. In field