220 Invasive Stink Bugs and Related Species (Pentatomoidea)
on the developing seed and seed pods of oil-seed brassicaceous plants, which eventually can restrict the
plant’s overall reproductive capacity (Verma et al. 1993, Rajpoot, et al. 1996, Malik et al. 2012, Banuelos
et al. 2013). Feeding on developing pods results in desiccation of seed pods and reduced oil content of
the seeds (Rajpoot et al. 1996). Adults also will excrete a black, sticky resinous material (likely feces
[John C. Palumbo, personal observations]) that can spoil the seed pods prior to harvest (Rajpoot, et al.
1996, Banuelos et al. 2013).
Feeding damage by Bagrada hilaris on other Old World host crops varies depending on crop type.
B. hilaris recently became a major pest of caper plants, Capparis spinosa L., in Italy, where its feeding
on the developing buds, stems, and foliage results in hollowed out plant parts, chlorotic spots, feeding
punctures, and leaf deformations (Colazza et al. 2004, Infantino et al. 2007). When B. hilaris first was
reported as a pest on potato, characteristic wilting of foliage on apical branches was attributed to the sap
feeding by adults and nymphs (Dharpure 2002b). Rizvi et al. (1986) reported that maize plants infested
with B. hilaris were wilted and stunted relative to non-infested plants. Feeding by B. hilaris on the
leaves, spikelets, and stems of wheat resulted in characteristic white blotches on the tissue, and plants
that were severely damaged, wilted, and collapsed (Rawat and Singh 1980). Feeding on pearl millet
caused damage to emerging heads (Gahukart and Jotwani 1980). Although considered only an occa-
sional pest of cotton, B. hilaris has been observed feeding on immature, green cotton bolls (Harris 1937).
Estimates of the impact of damage by Bagrada hilaris in crop losses in many cropping systems in the
Old World have been subjective. For example, Colazza et al. (2004) indicated that feeding by this bug
on caper plants is capable of causing significant economic crop losses. Nyabuga (2008) suggested that
the supply and quality of kale available in many parts of Kenya was low during the dry season due in
part to B. hilaris injury. Growers of rape, cabbage, and kale in Botswana considered B. hilaris the most
serious constraint to production because of its potential to cause crop losses if not adequately controlled
(Obopile et al. 2008). A few studies have provided quantitative estimates of yield reductions and crop
losses associated with B. hilaris infestations. Joshi et al. (1989) reported that in unprotected Indian mus-
tard crops, growers suffered reductions in seed yield as high as 70% due to B. hilaris damage. Similarly,
Ahuja et al. (2008) reported that mustard crops experienced 32% plant mortality and 37% reduction in
seed yield when B. hilaris was not controlled. Broccoli infested with B. hilaris during the vegetative and
head formation growth stages in the Eastern Hill Region of India was reported to suffer damage from
20–50% (Boopathi and Pathak 2012). Studies on kale showed that increases in B. hilaris population
density lead to corresponding increases in cosmetic damage to leaves and reductions in yield and quality
(Nyabuga 2008).
3.5.3 North America
In the United States, greater than 90% of the nation’s fresh-market brassicaceous crops are grown com-
mercially in the agricultural valleys of Arizona and California. When the first outbreaks of Bagrada
hilaris were reported in these growing locations in 2009, adults and nymphs were observed feeding
on direct-seeded and transplanted broccoli, cabbage, and cauliflower cultivars that produce marketable
crowns or heads as well as a number of leafy and root cultivars such as kale, radish, rutabaga, collards,
arugula, turnip, and mustard crops used for salads (Palumbo and Natwick 2010). Yield losses on these
crops occurred primarily from reductions in plant stand where seedling mortality exceeded 60% in
some broccoli fields during crop establishment (Reed et al. 2013b). Subsequent feeding by the pest on
established stands caused losses in yield and quality due to damaged terminal growing points, severely
stunted plants, as well as malformed or multi-headed plants, which are not commercially marketable
(Palumbo and Natwick 2010, Reed et al. 2013b, Sánchez-Peña 2014). Estimates by local growers indi-
cated that in 2009, injury from B. hilaris caused 20–25% losses in cauliflower and broccoli, respectively,
due to harvest delays, poor quality, and unacceptable product (blind plants or multiple crowns) (Reed et
al. 2013b). Growers further estimated that from 2010 to 2014, B. hilaris infested more than 80% of the
acreage in Arizona and southern California, resulting in excess of 10% stand losses and plant injury in
direct-seeded broccoli crops (Palumbo et al. 2015).
Seedling brassicaceous crops especially are susceptible to direct feeding damage by Bagrada hilaris on
cotyledons, newly emerged leaves, and apical meristems (Reed et al. 2013b). In Arizona and California,