Abstract There are specific regulations in the USA for the inter-state shipment of containerized citrus from production nurseries located within Diaphorina citri Kuwayama (Asian citrus psyllid; ACP) quarantine zones. To ensure trees are protected from the insect, nurseries must treat trees with an approved systemic neonicotinoid at least 30 days, and not more than 90 days, before trees can be shipped. The objective of this study was to reevaluate the necessity for a 30-day pre-shipment restriction by providing regulators with further data on the uptake of imidacloprid, thiamethoxam and dinotefuran, during the days immediately following treatments. In previous studies, ACP-effective thresholds were determined for 1-year old containerized citrus trees by correlating residue concentrations in leaf tissue with ACP efficacy. In this study, we used target concentrations to compare the uptake and retention of these neonicotinoids in 4 cultivars of 1-year old containerized citrus trees. ACP-effective thresholds were achieved within 3 days of treatment with the current lowest label rate (6.43 g AI/m3 soil) of generic formulations of imidacloprid, and within 1 day of treatment with the maximum label rate (97 g AI/m3 soil) of the name brand formulation Admire Pro®. The establishment of dinotefuran at ACP-effective thresholds was erratic in citrus cultivars, and residues of both dinotefuran and thiamethoxam had largely dissipated before the 30-day pre-shipment period had expired. The uptake and retention of all three neonicotinoids were significantly compromised under excessive watering (400% ET), although ACP-effective thresholds were still achieved with all imidacloprid treatment rates and thiamethoxam within 3 days. Overall, our results strongly support shortening the 30-day pre-shipment restriction to at most 3 days for trees treated with either imidacloprid or thiamethoxam. And, dinotefuran should be removed from the list of systemic insecticides approved for quarantine treatments.

中文翻译：

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在苗圃柑橘树中快速吸收和保留三种新烟碱类物质，以防止亚洲柑橘木虱（Diaphorina citri）侵染

摘要 美国对从位于 Diaphorina citri Kuwayama（亚洲柑橘木虱；ACP）检疫区内的生产苗圃运送集装箱柑橘的州际运输有具体规定。为确保树木免受昆虫侵害，苗圃必须使用经批准的全身性新烟碱类物质处理树木至少 30 天，且不超过 90 天，然后才能运输树木。本研究的目的是通过向监管机构提供有关吡虫啉、噻虫嗪和呋虫胺在治疗后几天内的摄入量的进一步数据，重新评估 30 天装运前限制的必要性。在之前的研究中，通过将叶组织中的残留浓度与 ACP 功效相关联，确定了 1 年生集装箱柑橘树的 ACP 有效阈值。在这项研究中，我们使用目标浓度来比较这些新烟碱类物质在 1 年生集装箱柑橘树的 4 个栽培品种中的吸收和保留。在使用吡虫啉仿制药的当前最低标记率（6.43 g AI/m3 土壤）处理后 3 天内达到 ACP 有效阈值，在最大标记率（97 g AI/m3 土壤）处理后 1 天内达到 ACP 有效阈值名牌配方 Admire Pro®。在柑橘品种中，呋虫胺在 ACP 有效阈值下的建立是不稳定的，并且在 30 天的装运前期到期之前，呋虫胺和噻虫嗪的残留物已基本消散。在过度浇水 (400% ET) 下，所有三种新烟碱类物质的吸收和保留都显着受损，尽管所有吡虫啉治疗率和噻虫嗪在 3 天内仍能达到 ACP 有效阈值。总体而言，我们的结果强烈支持将使用吡虫啉或噻虫嗪处理的树木的 30 天装运前限制缩短至最多 3 天。并且，应将呋虫胺从批准用于检疫处理的内吸性杀虫剂清单中删除。