230 Invasive Stink Bugs and Related Species (Pentatomoidea)
range is large, encompassing all or nearly all climatic and ecological subregions to which Bagrada
hilaris may be anticipated to spread in the New World. This bug is a sporadic pest from India and
Pakistan through Kenya to southern Africa. Throughout this broad geographic distribution there are
certainly regional guilds of parasitoids that keep populations in check most years in most places. The
fact that most eggs are uniquely deposited singly and in the soil must mean that host-specific species of
parasitoids have developed unique host finding cues. These will be quite different from those species
evolved to locate groups of eggs glued together on above-ground plant tissues. Such parasitoids also are
likely to possess different mating systems than the typical protandrous, sib-mated parasitoid species that
attack egg masses. The latter species are quasi-gregarious, have local mate competition, and female-
biased sex ratios.
Selection of biocontrol agents that are adapted to the climates in areas of intended release requires
a thorough analysis of the climates of the source and release sites. Currently, Bagrada hilaris still is
spreading south and east into new areas in North America. It has been intercepted many times in com-
mercial vehicles at the Florida border (LeVeen and Hodges 2015). Thus, it is likely that it will eventu-
ally become established in the southeastern states, which possess different climate types from those in
the Southwest. However, because most commercial cole crop production occurs in the desert valleys of
California and Arizona, these locations probably should be targeted first. An initial attempt to match
climates using the program CLIMEX (Sutherst and Maywald 1985, Sutherst et al. 2004) compared the
default settings for Bakersfield, California, with that of Africa. The closest matches within the African
distribution of B. hilaris was South Africa and immediately adjacent areas (W. A. Jones, unpublished
data). Preparations to make explorations in that region are underway.
An opportunity to explore Pakistan for Bagrada hilaris parasitoids appeared in 2013, which quickly
yielded three egg parasitoids that were successfully collected and shipped to the United States. The
United States Department of Agriculture – Agricultural Research Service (USDA-ARS) maintains the
European Biological Control Laboratory (EBCL) near Montpellier, France (Jones and Sforza 2007),
continuing classical biological explorations and research on invasive species begun in France in 1919.
The EBCL has maintained many collaborations on biological control projects with the Commonwealth
Agricultural Bureau International (CABI) South Asia laboratory, Rawalpindi, Pakistan. In 2013, EBCL
received permission to release some funds for an initial attempt at collecting egg parasitoids in Pakistan.
A contract was developed through the American Embassy, Paris. During 2014, personnel at CABI
Pakistan established a B. hilaris culture on cabbage, obtained eggs that were glued to paper cards and
placed in the field, both on the ground and on plants at two locations. Parasitoids were recovered and
parasitized host eggs shipped to the USDA-ARS Stoneville Research Quarantine Facility, Stoneville,
MS (Jones et al. 1985). Three species were colonized successfully on eggs from bugs shipped regularly
(under Animal and Plant Health Inspection Service permit) from California and New Mexico (Mahmood
et al. 2015). The three species of egg parasitoids tentatively were identified by E. Talamas (USDA-ARS,
Systematic Entomology Laboratory, Washington, D.C., USA) and K. Rahjmohana (Zoological Survey
of India, Calicut, India) as Gryon gonikopalense Sharma (Figure 3.10) and Trissolcus hyalinipennis
0.1 mmFIGURE 3.10 Gryon gonikopalense, egg parasitoid of Bagrada hilaris (lateral view). (Courtesy of Elijah J. Talamas and
Ashton B. Smith, USDA-ARS).