Citrus Research International, Walmer, Gqeberha, South Africa.
Centre for Biological Control, Department of Zoology and Entomology, Rhodes University, Makhanda, South Africa.
J Econ Entomol. 2022 Aug 10;115(4):1115-1128. doi: 10.1093/jee/toac064.
A systems approach was developed as an alternative to a standalone quarantine disinfestation treatment for Thaumatotibia leucotreta in citrus fruit exported from South Africa. The systems approach consists of three measures: pre and postharvest controls and measurements, postpacking inspection, and postharvest exposure to low temperatures. Different cold treatment conditions with a range of efficacy levels can be used for this last measure. A series of trials reported here evaluated the efficacy of seven temperatures ranging from 0 to 5°C for durations from 14 d to 26 d. Mortality of the most cold-tolerant larval stages of T. leucotreta was determined. Temperatures of 0, 1, 2, and 3°C for 16, 19, 20, and 24 d respectively, induced 100% mortality of the tested populations. Probit 9 level treatment efficacy was achieved at 0 and 1°C for 16 and 19 d respectively. Mortalities higher than 90% were obtained with temperatures of 4, 4.5, and 5°C, after exposure for the longer durations. We demonstrated a significant difference in cold-induced insecticidal efficacy between 1, 2, 3, and 4°C. There was no significant difference in insecticidal efficacy between 4 and 4.5°C, but both of these temperatures were more efficacious than 5°C. The results of this study are valuable to support the use of cold treatment conditions with lower risk of fruit chilling injury in an effective systems approach, where the cold treatment efficacy can be augmented with other components of the systems approach.
针对南非出口的柑橘水果中的橘潜跳甲，我们开发了一种系统方法，以替代单独的检疫除虫处理。该系统方法由三项措施组成：收获前和收获后的控制和测量、包装后检查以及收获后低温暴露。对于最后一项措施，可以使用不同的低温处理条件和一系列功效水平。这里报告的一系列试验评估了七种温度（范围从 0 到 5°C）持续 14 至 26 天的功效。确定了最耐寒的橘潜跳甲幼虫阶段的死亡率。0、1、2 和 3°C 下分别持续 16、19、20 和 24 天，可分别诱导测试种群 100%的死亡率。在 0 和 1°C 下分别持续 16 和 19 天可达到概率单位 9 级处理功效。4、4.5 和 5°C 下的暴露时间较长时，死亡率高于 90%。我们证明了 1、2、3 和 4°C 之间低温诱导杀虫功效存在显著差异。4 和 4.5°C 之间的杀虫功效没有显著差异，但这两种温度均比 5°C 更有效。本研究的结果对于支持使用低温处理条件具有重要意义，这些条件在系统方法中具有较低的果实冷害风险，并且低温处理的功效可以通过系统方法的其他组成部分来增强。
