Condon Catriona H, White Sabrina, Meagher Robert L, Jeffers Laura A, Bailey Woodward D, Hahn Daniel A
Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA.
USDA-ARS, Center for Medical and Veterinary Entomology, Gainesville, FL, USA.
J Econ Entomol. 2017 Feb 1;110(1):80-86. doi: 10.1093/jee/tow273.
Ionizing radiation is used as a phytosanitary treatment to mitigate risks from invasive species associated with trade of fresh fruits and vegetables. Commodity producers prefer to irradiate fresh product stored in modified atmosphere packaging that increases shelf life and delays ripening. However, irradiating insects in low oxygen may increase radiation tolerance, and regulatory agencies are concerned modified atmosphere packaging will decrease efficacy of radiation doses. Here, we examined how irradiation in a series of oxygen conditions (0.1-20.9 kPa O2) alters radiotolerance of larvae and pupae of a model lepidopteran Trichoplusia ni (Hubner) (Diptera: Noctuidae). Irradiating in severe hypoxia (0.1 kPa O2) increased radiation tolerance of insects compared with irradiating in atmospheric oxygen (20.9 kPa O2). Our data show irradiating pharate adult pupae at 600 Gy in moderately severe hypoxia (5 kPa O2) increased adult emergence compared with irradiation in atmospheric oxygen (20.9 kPa O2). Our data also show that in one of the three temporal replicates, irradiating T. ni larvae in moderately severe hypoxia (5 kPa O2) can also increase radiotolerance at an intermediate radiation dose of 100 Gy compared with irradiating in atmospheric oxygen conditions, but not at higher or lower doses. We discuss implications of our results in this model insect for the current generic doses for phytosanitary irradiation, including the recently proposed 250 Gy generic dose for lepidioptera larvae, and temporary restriction on irradiating commodities in modified atmosphere packaging that reduces the atmosphere to < 18 kPa O2.
电离辐射被用作一种植物检疫处理方法，以降低与新鲜水果和蔬菜贸易相关的入侵物种带来的风险。商品生产者更倾向于对储存在气调包装中的新鲜产品进行辐照，这种包装可以延长保质期并延缓成熟。然而，在低氧环境下辐照昆虫可能会提高其辐射耐受性，监管机构担心气调包装会降低辐射剂量的效果。在此，我们研究了在一系列氧气条件（0.1 - 20.9 kPa O₂）下进行辐照如何改变模式鳞翅目昆虫粉纹夜蛾（Trichoplusia ni (Hubner)）（双翅目：夜蛾科）幼虫和蛹的辐射耐受性。与在大气氧含量（20.9 kPa O₂）下辐照相比，在严重缺氧（0.1 kPa O₂）条件下辐照会提高昆虫的辐射耐受性。我们的数据表明，在中度严重缺氧（5 kPa O₂）条件下以600 Gy辐照预蛹期成虫，与在大气氧含量（20.9 kPa O₂）下辐照相比，成虫羽化率有所提高。我们的数据还表明，在三个时间重复实验中的一次实验里，与在大气氧条件下辐照相比，在中度严重缺氧（5 kPa O₂）条件下辐照粉纹夜蛾幼虫，在100 Gy的中等辐射剂量下也能提高其辐射耐受性，但在更高或更低剂量下则不然。我们讨论了我们在这种模式昆虫上的研究结果对当前植物检疫辐照通用剂量的影响，包括最近提议的针对鳞翅目幼虫的250 Gy通用剂量，以及对气调包装商品进行辐照的临时限制，即当包装内氧气含量降至<18 kPa O₂时。
