Since methyl bromide has been phased out and recently banned in many countries, and resistance to phosphine has developed and spread worldwide, alternative fumigants are a high priority for stored product pests. The present study evaluated the fumigant activity of methyl benzoate (MB) and acetophenone (AP) against the lesser grain borer, , the rice weevil, , and the red flour beetle, under laboratory conditions. Methyl benzoate and AP exerted a significant toxicity against the different life stages of tested insects. The LC values of MB were 10.52, 12.69, and 15.53 μl/L for , , and adults, respectively. The larvae of were the most tolerant stage for that species, with an LC value of 44.26 μl/L followed by the pupae (LC = 18.54 μl/L) and adults. The LC values of AP were 18.59, 13.15, and 25.85 μl/L against adults of , , and , respectively. Also, the larvae of were the most tolerant, with an LC value of 150.11 μl/L followed by pupae at LC = 70.07 μl/L and adults. MB and AP showed significant activity against mixed life stage cultures of these beetles at concentrations of 100, 200, and 300 μl/L compared to untreated controls. However, these concentrations of both compounds were ineffective at achieving 100% control of these species. This poor control of mixed cultures was likely due to tolerance of immature stages and also the potential sorption of fumigants in the host material reducing the gas concentrations available in the treatment chambers. An inhibition assay of acetylcholine esterase (AChE) in larvae showed that MB and AP significantly inhibited the activity of AChE with IC values of 55.38 and 32.89 mM, respectively. The results from this research suggest that MB and AP could be promising alternative fumigants for protecting stored products from insect pests.

中文翻译：

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苯甲酸甲酯及其衍生物苯乙酮作为熏蒸剂控制储品昆虫

由于许多国家已逐步淘汰并最近禁止使用甲基溴，并且对磷化氢的抗性已在全球范围内发展和蔓延，因此替代熏蒸剂是储存产品害虫的高度优先考虑。本研究在实验室条件下评估了苯甲酸甲酯 (MB) 和苯乙酮 (AP) 对小谷螟、稻象甲和红面甲虫的熏蒸活性。苯甲酸甲酯和AP对受试昆虫的不同生命阶段均产生显着的毒性。、 、 和成虫MB的LC值分别为10.52、12.69和15.53 μl/L。幼虫是该物种耐受性最强的阶段，LC 值为 44.26 μl/L，其次是蛹 (LC = 18.54 μl/L) 和成虫。AP 对 、 、 和 成虫的 LC 值分别为 18.59、13.15 和 25.85 μl/L。此外，幼虫的耐受性最强，LC 值为 150.11 μl/L，其次是蛹，LC 为 70.07 μl/L，最后是成虫。与未处理的对照相比，MB 和 AP 在浓度为 100、200 和 300 μl/L 时对这些甲虫的混合生命阶段培养物表现出显着的活性。然而，这两种化合物的这些浓度无法有效实现对这些物种的 100% 控制。对混合培养物的这种不良控制可能是由于对未成熟阶段的耐受性以及宿主材料中熏蒸剂的潜在吸附降低了处理室中可用的气体浓度。幼虫乙酰胆碱酯酶 (AChE) 抑制实验表明，MB 和 AP 显着抑制 AChE 活性，IC 值分别为 55.38 和 32.89 mM。这项研究的结果表明，MB 和 AP 可能是有前途的替代熏蒸剂，用于保护储存产品免受害虫侵害。