Citrus Research International, PO Box 28, Mbombela 1200, South Africa.
Department of Conservation Ecology and Entomology, Faculty of AgriSciences, Stellenbosch University, Stellenbosch, South Africa.
J Econ Entomol. 2023 Jun 13;116(3):779-789. doi: 10.1093/jee/toad063.
The efficacy of an existing cold disinfestation postharvest treatment targeting Ceratitis capitata (Wiedemann) in citrus was determined for the marula fly, Ceratitis cosyra (Walker). The cold tolerances of C. capitata and C. cosyra were first quantified in artificial diet at 3.5 °C at different exposure periods for up to 18 days. Ceratitis capitata was found to be more cold tolerant than C. cosyra. At 3.5 °C, the duration to achieve 99.9968% mortality was calculated to be 11.57 days for C. capitata and 9.10 days for C. cosyra. Under an existing C. capitata cold treatment schedule at 1 °C for 14 days, the conditions required for complete mortality of the third larval stage of C. cosyra in orange, Citrus sinensis (L.) Osbeck cv. Valencia, were then determined. No survivors of C. cosyra in oranges were recorded beyond 11 days of cold treatment at 1 °C. The efficacy of this C. capitata treatment for disinfestation of C. cosyra was thereafter confirmed in large scale trials in Valencia oranges. In the large-scale trial at the lowest mean temperature of 1.19 °C for 14 days, there were no survivors from a total of 85 490 treated C. cosyra third instars in oranges. Since C. capitata was shown to be more cold tolerant than C. cosyra and a large scale test demonstrated at least 99.9965% efficacy after 14 days at 1.19 °C, compared with the established effective C. capitata cold treatment of 14 days at 1.11 °C, cold disinfestation treatments for C. capitata should be at least equally effective against C. cosyra.
为评估现有冷消毒处理方案对南非蜡实蝇（Ceratitis cosyra）的防治效果，针对地中海实蝇（Ceratitis capitata）开展了相关研究。首先在人工饲料中于 3.5°C 下，量化了 C. capitata 和 C. cosyra 的冷耐受能力，并评估了它们在不同暴露时间下（最长 18 天）的冷耐受能力。结果表明，C. capitata 比 C. cosyra 更能耐受低温。在 3.5°C 下，C. capitata 达到 99.9968%死亡率所需的时间为 11.57 天，而 C. cosyra 则为 9.10 天。在 1°C 下进行为期 14 天的现有 C. capitata 冷处理方案下，然后确定了甜橙（Citrus sinensis (L.) Osbeck cv. Valencia）中第三龄幼虫完全死亡所需的条件。在 1°C 下冷处理 11 天后，甜橙中没有南非蜡实蝇存活。此后，在 Valencia 甜橙的大规模试验中证实了这种 C. capitata 处理方案对 C. cosyra 的防治效果。在最低平均温度为 1.19°C 下进行为期 14 天的大规模试验中，共有 85490 头处理过的 C. cosyra 第三龄幼虫，无任何存活个体。由于 C. capitata 比 C. cosyra 更能耐受低温，且在 1.19°C 下 14 天后的大规模试验中，防治效果至少为 99.9965%，而现有的有效 C. capitata 冷处理方案为 14 天 1.11°C，因此，冷消毒处理方案对 C. capitata 至少应与对 C. cosyra 同样有效。
