Abstract Plant-based products and common repellents have been suggested as promising alternatives for management of stored product insects. In this study, contact toxicity and repellent activity of the safe natural products carvacrol, citronella oil, geraniol, nootkatone, ocimene and R-(+)-pulegone, and the synthetic commercial repellents, N,N-Diethyl-3-methylbenzamide (DEET), and the fatty acid mixture of octanoic, nonanoic, and decanoic acids (C8910) were evaluated against the lesser grain borer, Rhyzopertha dominica and the cigarette beetle, Lasioderma serricorne under laboratory conditions. In contact toxicity assays the compounds were tested at concentrations ranging between 0.008 and 0.4 mg/cm2. Carvacrol and R-(+)-pulegone exhibited the highest contact toxicity with LC50 values of 0.019 and 0.023 mg/cm2 against L. serricorne and LC50 values of 0.012 and 0.019 mg/cm2 against R. dominica, respectively. Similarly, C8910, geraniol and citronella oil showed toxic effect against both insects. The repellent activity of compounds was tested using the preference method assay at concentrations ranging between 3.125 and 50.0 μg/cm2. The highest repellency percentage (RP) was achieved by C8910 against L. serricorne with a RP value of 76.0% at the lowest concentration (6.25 μg/cm2), while carvacrol showed the highest repellent activity against R. dominica with RP value of 88.0% at 3.125 μg/cm2 within 3 h of insect exposure. The tested compounds caused higher repellent activity to R. dominica than L. serricorne. In vitro inhibition studies of acetylcholinesterase (AChE) in adults of both species showed that R-(+) pulegone strongly inhibited AChE activity of R. dominica and L. serricorne with 69.0% and 88.0% inhibition at 40 mM, respectively. Carvacrol caused 41.8% inhibition in AChE activity of R. dominica compared to 66.7% of L. serricorne at 40 mM. The results indicated that the tested natural compounds may be useful alternatives for controlling R. dominica and L. serricorne.

中文翻译：

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萜类化合物、避蚊胺和短链脂肪酸作为毒物和驱虫剂，可用于多米尼克（鞘翅目：Bostrichidae）和 Lasioderma serricorne（鞘翅目：Ptinidae）

摘要 植物性产品和常见驱虫剂已被认为是管理储藏产品昆虫的有前途的替代品。在本研究中，安全天然产品香芹酚、香茅油、香叶醇、诺卡酮、罗勒烯和 R-(+)-胡薄荷酮以及合成商业驱虫剂 N,N-二乙基-3-甲基苯甲酰胺 (DEET) 的接触毒性和驱虫活性)，并在实验室条件下对辛酸、壬酸和癸酸的脂肪酸混合物 (C8910) 与较小的螟螟、Rhyzopertha dominica 和卷烟甲虫 Lasioderma serricorne 进行了评估。在接触毒性试验中，化合物在 0.008 至 0.4 mg/cm2 的浓度范围内进行测试。Carvacrol 和 R-(+)-pulegone 表现出最高的接触毒性，对 L 的 LC50 值为 0.019 和 0.023 mg/cm2。serricorne 和 LC50 值分别为 0.012 和 0.019 mg/cm2 对 R. dominica。同样，C8910、香叶醇和香茅油对这两种昆虫均显示出毒性作用。在 3.125 和 50.0 μg/cm2 之间的浓度范围内使用偏好方法测定测试化合物的驱避活性。C8910 在最低浓度 (6.25 μg/cm2) 下对 L. serricorne 的驱避率 (RP) 最高，RP 值为 76.0%，而香芹酚对多米尼加罗勒表现出最高的驱避活性，RP 值为 88.0%在接触昆虫 3 小时内，浓度为 3.125 μg/cm2。与 L. serricorne 相比，测试的化合物对多米尼克红藻的驱避活性更高。两种物种成人乙酰胆碱酯酶 (AChE) 的体外抑制研究表明，R-(+) 胡薄荷酮强烈抑制 R 的 AChE 活性。dominica 和 L. serricorne 在 40 mM 下分别具有 69.0% 和 88.0% 的抑制作用。香芹酚在 40 mM 时对多米尼加红豆杉的 AChE 活性产生 41.8% 的抑制，而对 L. serricorne 则抑制 66.7%。结果表明，测试的天然化合物可能是控制 R. dominica 和 L. serricorne 的有用替代品。