224 Invasive Stink Bugs and Related Species (Pentatomoidea)
plants (Palumbo et al. 2015). Neonicotinoid seed treatments showed that planting mustard seeds treated
with imidacloprid resulted in significantly lower plant injury due to B. hilaris (Ameta et al. 2005, Ahuja
et al. 2008). In Arizona, clothianidin-treated seeds protected broccoli seedlings from B. hilaris injury
through the three-leaf plant stage under field conditions (J. C. Palumbo, unpublished data).
Several other new classes of insecticide chemistry with known activity against piercing-sucking pests
have been developed (e.g., anthranillic diamides, sulfoxamines, ketoenols, spinosyns), but research with
Bagrada hilaris has indicated that these new insecticides are only marginally effective (Palumbo 2012;
Palumbo et al. 2013c, d; Palumbo and Huang 2014b; Palumbo et al. 2015).
Similarly, botanical and biorational insecticides have been evaluated for control of Bagrada hilaris.
The evaluation of neem oil/extracts and azadirachtin products in numerous laboratory bioassays and field
trials indicated that efficacy of these materials varied widely depending on the life stage of B. hilaris used
or other experimental variables such as the extraction processes of the compound, formulation of sprayed
product, concentration applied, and spray timing/frequency (Pandey et al. 1981, Charleston et al. 2006,
Guarino et al. 2007, Ahuja et al. 2008, Nyabuga 2008, Chandel et al. 2011, Grasswitz 2013b, Palumbo et
al. 2013a). Other botanical insecticides such as pyrethrin, rotenone, sabadilla, chili extract, garlic extract,
insecticidal soaps, and numerous exotic plant extracts also have been evaluated for biological activity
against B. hilaris with variable results (Verma and Pandey 1981, Johri et al. 2004, Charleston et al. 2006,
Guarino et al. 2007, Nyabuga 2008, Chandel et al. 2011, Grasswitz 2013b, Palumbo et al. 2013a).
To date, there has been no strong evidence that Bagrada hilaris populations have evolved resistance
to insecticides under field conditions. However, Infantino et al. (2007) suggested that increasing damage
caused by Bagrada hilaris on insecticide-treated caper crops in Italy likely is due to the development of
insecticide resistance. Furthermore, bioassay monitoring of B. hilaris populations in India showed that
the LC 50 values of some organophosphate and organochlorine insecticides increased significantly over
a 25-year span, but corroborative evidence indicating failure of insecticide efficacy in the field has not
been reported (Swaran Dhingra 1998). For North American populations, baseline susceptibility data
recently generated for B. hilaris populations from Arizona and southern California (Palumbo et al. 2015)
will become increasingly important in the future given the reliance on pyrethroids, organophosphates,
and neonicotinoids for control of B. hilaris and other key insect pests in brassica crops (Palumbo 2015a).
3.6.2 Organic Cropping Systems
At present, there is little published research on the management of Bagrada hilaris in organic produc-
tion systems. In the United States, management of B. hilaris in such systems poses particular problems
because of the limited number and efficacy of organically acceptable insecticides and the lack of effec-
tive native natural enemies (Lawrence 2012). Furthermore, the seasonal phenology of this bug varies
between regions in the United States, making it difficult to use recommendations broadly across these
regions. Management guidelines developed in one location may not be fully transferrable to another. In
New Mexico, for example, many of the state’s small-scale organic farmers produce a variety of crops
within the Brassicaceae (including arugula, various leafy mustard greens, broccoli, radishes, kale, and
turnips). However, the timing of production of these crops varies widely depending on latitude and alti-
tude within the state and with the use of season-extending techniques such as floating row covers and
hoop-houses. Also, the phenology of B. hilaris may vary within the state (Tessa R. Grasswitz, personal
observations), reflecting differences in seasonal temperatures and host availability. For these reasons,
strategies such as adjusting planting dates to avoid peak Bagrada populations must be synchronized with
the pest’s seasonal history in the target area(s).
With this caveat in mind, the best approach to managing Bagrada hilaris is to use a combination of
control tactics. In this respect, pest management in organic systems is similar to that in conventional
farming (Dufour 2001). Possible organic management tactics for B. hilaris are discussed below.
3.6.2.1 Planting Date and Crop Selection
A combination of judicious crop choices and planting dates may allow organic growers to produce via-
ble crops in periods when Bagrada hilaris is dormant or absent. In central New Mexico, for example,