Factors Affecting Ionizing Radiation Phytosanitary Treatments, and Implications for Research and Generic Treatments

Abstract

Phytosanitary irradiation (PI) treatments are promising measures to overcome quarantine barriers to trade and are currently used in several countries. Although PI has advantages compared with other treatments one disadvantage bedevils research, approval, and application: organisms may remain alive after importation. Although this does not preclude their use as a phytosanitary treatment, it does leave the treatment without an independent verification of efficacy and places a greater burden for assuring quarantine security on the research supporting the treatment. This article analyses several factors that have been hypothesized to affect PI efficacy: low oxygen, pest stage, host, dose rate, and temperature. Of these factors, the first is known to affect efficacy, whereas host and dose rate probably need more research. The International Plant Protection Convention considered several PI treatments for its international standard on phytosanitary treatments and did not approve some at first because of perceived problems with the research or the presence of live adults after irradiation. Based on these concerns recommendations for research and dealing with the issue of live adults postirradiation are given. Generic PI treatments are suggested.

Short-term anoxic conditioning hormesis boosts antioxidant defenses, lowers oxidative damage following irradiation and enhances male sexual performance in the Caribbean fruit fly, Anastrepha suspensa

“…Furthermore, higher percentages of the anoxic conditioned flies were able to fully emerge and extend their wings, enabling successful flight at the very high 300 and 400Gy doses. Survival at these high doses is of particular interest because current phytosanitary treatments are being developed involving hypoxic and anoxic controlled atmosphere environments prior to irradiation at high doses (Hallman, 1999;Hallman et al, 2010). These reduced oxygen quarantine treatments have the potential of triggering conditioning hormesis in insects, allowing them to survive the higher doses used in phytosanitary irradiation.…”

Electron beam processing as a phytosanitary treatment of imported fruits

“…The USDA Animal and Plant Health Inspection Service (APHIS) approved generic treatment regulations in 2006 that stipulate that treatment using irradiation is approved for all fresh horticultural commodities at 150 Gy for tephritid fruit fl y infestations and at 400 Gy for any other insects, excluding Lepidoptera adults and pupae (Follett, 2009;Hallman et al ., 2010). As a result, irradiation is the "broadest commercially applicable treatment in existence" for imports in the USA, permitted for use on almost any type of fresh produce if pest risk assessment requirements are met (Hallman, 2011).…”

“…This is an issue because, for all other quarantine treatment methods, the presence of live pests indicates that treatment either was not performed or was performed insuffi ciently and will result in the shipment being rejected or destroyed (Hallman, 2011;Cannon et al ., 2012). Several authors and experts in the fi eld have listed this lack of acute insect mortality as one of the primary challenges facing the use of irradiation as a phytosanitary treatment (Cannon et al ., 2012;Hallman et al ., 2010;Torres-Rivera and Hallman, 2007). This issue is certainly not insurmountable, especially considering irradiation's many other benefi ts, but it puts irradiation at a disadvantage, because inspectors cannot visually confi rm the absence of pests and must instead rely on a certifi cate or other proof of treatment (Hallman, 2011).…”

Management ofSitotroga cerealellain stored cereal grains: a review

“…Use of irradiation is less damaging to fresh commodities when compared with temperature alternation and fumigation treatments (Hallman 2011). But oxygen concentration, kind of pest and temperature in storage can affect the efficacy of irradiation used (Hallman et al 2010). Among physical control measures, high temperature or gamma radiation can significantly control the S. cerealella (Alrubeal 1987).…”