|TAGAMI, Y - University Of Hawaii|
|KALUNA, L - University Of Hawaii|
|JARVI, S - University Of Hawaii|
Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2021
Publication Date: 12/8/2021
Citation: Follett, P.A., Hamilton, L.J., Tagami, Y., Kaluna, L., Jarvi, S. 2021. Phytosanitary irradiation using X-rays prevents reproduction in the semi-slug Parmarion martensi (Stylommatophora: Ariophantidae), a host of the human pathogenic nematode Angiostrongylus cantonensis (Rhabditida: Angiostrongylidae. Pest Management Science. 78(3):1187-1193. https://doi.org/10.1002/ps.6735.
Interpretive Summary: The semi-slug, Parmarion martensi, is an intermediate host of the zoonotic nematode Angiostrongyliasis cantonensis, the aetiological agent of neuroangiostrongyliasis or rat lungworm disease in humans. This slug has been found on exported Hawaii produce (e.g. sweet potatoes) and floriculture crops and is therefore a pest of quarantine concern and a health risk. Phytosanitary irradiation at 150 and 400 Gy completely sterilzed P. martensi slugs of different ages and prevented reproduction, but irradiated slugs continued to move normally and feed, albeit less, for several weeks after treatment. Irradiation treatment of fruits and vegetables at doses > 150 Gy will prevent movement of viable P. martensi slugs to export markets but may not eliminate the risk of transmitting A. cantonensis in non-viable but live P. martensi.
Technical Abstract: Phytosanitary irradiation treatment at 150-400 Gy is used to control quarantine insect pests in fresh fruit and vegetables exported from Hawaii to the continental United States. The semi slug, Parmarion martensi, has been found on exported Hawaii produce (e.g. sweet potatoes) and floriculture crops and is a quarantine pest of concern. P. martensi, is also an intermediate host of the zoonotic nematode Angiostrongyliasis cantonensis, the aetiological agent of neuroangiostrongyliasis or rat lungworm disease in humans. Rats serve as the definitive host for A. cantonensis and they acquire the nematode by eating P. martensi and other intermediate hosts. A study was conducted to determine if phytosanitary irradiation could control P. martensi and thereby reduce the risk of transmitting A. cantonensis in the U.S. Two-, 12-, and 21-week old P. martensi were treated with a radiation dose of 150 or 400 Gy or left untreated as a control then held in the laboratory while recording survivorship and reproduction every 2-3 days and measuring individual weights biweekly. Irradiation at 150 and 400 Gy caused reduced growth and a higher rate of mortality compared to untreated control slugs and prevented reproduction. However, irradiated slugs continued to move and feed for many weeks before dying. Phytosanitary irradiation treatment of fruits and vegetables at doses > 150 Gy will prevent movement of viable P. martensi slugs but may not eliminate the risk of transmitting A. cantonensis in non-viable but live P. martensi. Exported nursery and floriculture crops are not irradiated and therefore provide a significant pathway for movement of live P. martensi and transmission of A. cantonensis.