Sterile Insect Technique Applied to a Pentatomid Pest Species: Effects of Gamma Irradiation on the Fecundity, Fertility and Longevity of the bagrada bug, Bagrada hilaris (Hemiptera: Pentatomidae)

Authors: CRISTOFARO, MASSIMO - Bbca-Onlus, Italy; SFORZA, RENE - European Biological Control Laboratory (EBCL); ROSELLI, GERARDO - Bbca-Onlus, Italy; PAOLINI, ALESSANDRA - Bbca-Onlus, Italy; CEMMI, ALESSIA - Enea Casaccia Research Center; MUSMECI, SERGIO - Enea Casaccia Research Center; ANFORA, GIANFRANCO - Fondazione Edmund Mach; MASSONI, VALERIO - Fondazione Edmund Mach; Grodowitz, Michael

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/26/2022
Publication Date: 8/30/2022
Citation: Cristofaro, M., Sforza, R., Roselli, G., Paolini, A., Cemmi, A., Musmeci, S., Anfora, G., Massoni, V., Grodowitz, M.J. 2022. Sterile Insect Technique Applied to a Pentatomid Pest Species: Effects of Gamma Irradiation on the Fecundity, Fertility and Longevity of the bagrada bug, Bagrada hilaris (Hemiptera: Pentatomidae). Insects. 13(9), 787. https://doi.org/10.3390/insects13090787.
DOI: https://doi.org/10.3390/insects13090787

Interpretive Summary: Controlling alien insect pests, such as stinkbugs, in cropping systems with no use of chemicals has always been challenging. Herein, research studies to evaluate the use of irradiation to determine the suitability of using the sterile insect technique (SIT) approach to control the stinkbug Bagrada hilaris are described. Bagrada bug or painted bug is reported as a major pest of cole crops in its native range of eastern and southern Africa and the Indian subcontinent. In 2008, it was first reported in California, where it now attacks a wide range of Brassicaceae crops, including cabbage, broccoli, and radish. The bug has spread to New Mexico, Mexico, Hawaii, and Chile. To date, no efficient monitoring tools exist to long-term manage Bagrada bug populations in North America. The economic loss and the lack of alternative control practices, led U.S. growers to use broad-spectrum insecticides to reduce local pest populations. This work on SIT, complements investigations on biological control for some of the major pentatomid pests, e.g. brown marmorated stinkbug, the southern green stink bug or bagrada bug using specific egg parasitoids. Complete sterility of males and females was reached with a minimum of 80Gy Gamma irradiation dose. This study documented how various irradiation doses impact the life history parameters of bagrada bug, B hilaris, such as fertility, fecundity and longevity. The results warrant further research to test SIT directly on bagrada bug populations in the field, and other stinkbug species, or combine the SIT with a classical biological control program.

Technical Abstract: Bagrada bug, Bagrada hilaris, is an invasive insect pest causing economically important damage to crops in the family Brassicaceae. It was originally present in Asia, the Middle East, and Africa, and reported as invasive in the southwestern part of the U.S., in Chile and in few islands in the Mediterranean Basin. In its native range, B. hilaris is controlled by several egg parasitoid species that are under consideration as potential biological control agents. This research evaluated the impact of irradiation to determine the suitability of using the sterile insect technique (SIT) approach to control B. hilaris. Newly emerged adults of a laboratory colony originally collected from the island of Pantelleria (Italy), were Gamma-irradiated at nine different doses, ranging from 16 Gy to 140 Gy. Life history parameters such as fertility, fecundity and longevity were evaluated. The minimal dose to achieve full sterility was 80 Gy. Irradiation up to maximum of 140 Gy apparently did not negatively impact longevity of the adults. Even if both genders are sensitive to irradiation, the decline in fecundity for irradiated females could be exploited to release irradiated males safely to apply SIT in combination with classical biological control. More research is warranted on the competitive fitness of irradiated males and to better understand mating behavior as well as elucidating the possible mechanisms of sperm selection by polyandric B. hilaris females.