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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Invasive Species and Pollinator Health » Research » Publications at this Location » Publication #416423
Research Project: Biological Control of Invasive Pests in Agroecosystems and Wetland, Forest and Rangeland Ecosystems in the Far Western U.S.

Location: Invasive Species and Pollinator Health

Title: Improving the efficiency and safety of sentinel stink bug eggs using x-rays

Author
item Hougardy, Evelyne
item Haff, Ronald - Ron
item Hogg, Brian

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/2/2024
Publication Date: 10/4/2024
Citation: Hougardy, E.H., Haff, R.P., Hogg, B.N. 2024. Improving the efficiency and safety of sentinel stink bug eggs using x-rays. Insects. 15/767. https://doi.org/10.3390/insects15100767.
DOI: https://doi.org/10.3390/insects15100767

Interpretive Summary: Bagrada bug is an invasive stinkbug pest of cole crops (cabbage, broccoli, cauliflower, kale, etc.) in the United States. Pesticides are often ineffective against bagrada bugs because they persist in natural habitats surrounding crop fields where pesticides are not applied. Two parasitic wasps were found attacking bagrada bug eggs in California recently. Field monitoring of these parasitic wasps is usually done using stink bug eggs reared in the laboratory. However, these eggs can only be placed in the field for a few days and must be retrieved before the eggs hatch to avoid releasing the stink bug pest in the monitored area. In this study, x-ray irradiation was used to sterilize the bagrada eggs. Both parasitic wasps were able to successfully parasitize irradiated eggs. Our results showed that x-ray irradiation is a suitable method to produce safe and reliable sentinel eggs to monitor egg parasitism of the bagrada bug and possibly other species.

Technical Abstract: To monitor impacts of natural enemies on stinkbug eggs, eggs are typically harvested from lab-reared stinkbug colonies and placed in the field. Lab-reared eggs are more commonly used because searching for naturally laid eggs in the field is time-consuming and not always practical. Eggs of most stinkbugs hatch in less than one week, and eggs can be deployed in the field for only a few days, to avoid releasing the pest into the monitored area. Using sterile eggs removes the risk of accidental pest introduction and extends deployment time. Freezing the eggs before deployment is one common method for sterilizing sentinel eggs. However, some parasitic wasps will not parasitize frozen eggs. In this study, x-rays were used to sterilize eggs of the invasive stinkbug pest bagrada bug, and suitability of the irradiated eggs for two parasitic wasps was tested. The lowest dose tested (10 Gy) induced sterility. Both parasitic wasps were able to develop on irradiated eggs, and parasitism levels were comparable to fresh non-irradiated eggs. In addition, one wasp showed no preference for fresh non-irradiated over seven-day-old irradiated eggs. Our results indicate that x-ray irradiation is a suitable alternative to produce safe and reliable eggs to monitor parasitism of bagrada bug and possibly other stinkbug pests.