Live organisms intercepted from treated commodities during phytosanitary inspections usually arouse suspicions of treatment failure, sub-standard treatment application, or post-treatment infestation. The additional possibility that some treatments could kill slowly, meaning commodities might be inspected before pests have succumbed, is seldom considered for treatments other than irradiation. We used a novel biochemical viability assay to measure delays between methyl bromide fumigation and mortality of dipteran eggs, and evaluated the correspondence between egg viability and egg morphological features. Our experimental conditions simulated shipping of rock melons from Australia to New Zealand by sea and air. No eggs survived fumigation, but they took 3–20 days to die, whereas phytosanitary inspections of rock melons occur within 2–7 days. Delays were not influenced by methyl bromide concentration, but were significantly lengthened by cooler storage temperatures. Methyl bromide’s preservative effects delayed degradation of egg morphology, so the biochemical assay detected mortality long before morphological signs of egg death appeared. The results show that commodities subjected to effective methyl bromide treatments are at risk of being inspected before all pests have either died, or started to exhibit morphological signs of death. This could cause commodities to be unnecessarily rejected by quarantine authorities. Better methods than inspection for live pests are needed to assist authorities to gain assurance that treated commodities have been effectively disinfested. These could be developed by exploiting biochemical responses of pests and commodities to treatments.

中文翻译：

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甲基溴熏蒸和延迟死亡：活虫害的安全贸易？

在植物检疫检查中从经过处理的商品中截获的活生物通常会引起对处理失败，不合格处理应用或处理后感染的怀疑。除了辐射以外，很少考虑某些处理可能缓慢杀死的其他可能性，这意味着可以在有害生物死去之前检查商品。我们使用了一种新颖的生化活力测定法来测量甲基溴熏蒸和双壳类动物卵死亡之间的延迟，并评估了卵活力与卵形态特征之间的对应关系。我们的实验条件模拟了海上和空运从澳大利亚到新西兰的岩瓜运输。熏蒸过程中没有卵存活下来，但是它们花了3–20天才能死亡，而岩瓜的植物检疫检查则在2–7天之内进行。延迟时间不受甲基溴浓度的影响，但由于凉爽的储存温度而显着延长了延迟时间。甲基溴的防腐作用延缓了鸡蛋形态的降解，因此生化分析早在鸡蛋死亡的形态学迹象出现之前就检测到了死亡率。结果表明，经过有效甲基溴处理的商品有可能在所有害虫死亡或开始表现出死亡的形态迹象之前被检查。这可能导致检疫部门不必要地拒绝商品。需要一种比活害虫检查更好的方法，以协助当局确保已对经过处理的商品进行有效除虫。这些可以通过利用有害生物和商品对处理的生化反应来开发。