Paudel Pradeep, Shah Farhan Mahmood, Guddeti Dileep Kumar, Ali Abbas, Chen Jian, Khan Ikhlas A, Li Xing-Cong
National Center for Natural Products Research, The University of Mississippi, University, MS 38677, USA.
Biological Control of Pests Research Unit, USDA-ARS, Stoneville, MS 38776, USA.
Insects. 2023 Sep 28;14(10):790. doi: 10.3390/insects14100790.
In the United States, imported fire ants are commonly referred to as red imported fire ants ( Buren), black imported fire ants ( Forel), and hybrid imported fire ants ( × ). They are significant pests, and their control heavily relies on synthetic insecticides. The extensive use of insecticides has led to public concern about their potential negative effects on human health and the well-being of wildlife and the environment. As an alternative, plant-derived natural compounds, particularly essential oils (EOs) and their main constituents, show promise as safe and environmentally friendly products for controlling fire ants. Repellants are useful in managing fire ants, and plant-derived natural repellants may serve as a safer and more environmentally friendly option. This study investigates the repellency of EO-derived compounds carvacrol, thymol, and their acetates against imported fire ant workers. The results revealed that carvacrol, a GRAS compound (Generally Recognized As Safe), was the most potent repellent against , , and their hybrid, with minimum repellent effective doses (MREDs) of 0.98 µg/g, 7.80 µg/g, and 0.98 µg/g, respectively. Thymol also exhibited strong repellency, with MREDs of 31.25 µg/g, 31.25 µg/g, and 7.8 µg/g, respectively. Furthermore, thyme-red essential oil, characterized by a thymol chemotype containing 48.8% thymol and 5.1% carvacrol, was found to effectively repel the hybrid ants with an MRED of 15.6 µg/g. In contrast, thyme essential oil, characterized by a linalool chemotype lacking thymol and carvacrol, did not exhibit any repellent effect, even at the highest tested dose of 125 µg/g. This study provides the first evidence of the potent repellency of carvacrol and thymol against imported fire ant workers, indicating their potential as promising repellents for fire ant control.
在美国，外来入侵红火蚁通常被称为红色外来入侵红火蚁（布伦）、黑色外来入侵红火蚁（福雷尔）和杂交外来入侵红火蚁（×）。它们是重要害虫，对其防治严重依赖合成杀虫剂。杀虫剂的广泛使用引发了公众对其对人类健康、野生动物福祉和环境潜在负面影响的担忧。作为替代方案，植物源天然化合物，尤其是精油（EOs）及其主要成分，有望成为控制红火蚁的安全且环保的产品。驱避剂在红火蚁防治中很有用，植物源天然驱避剂可能是更安全、更环保的选择。本研究调查了源自精油的化合物香芹酚、百里香酚及其醋酸酯对进口红火蚁工蚁的驱避作用。结果表明，香芹酚是一种一般认为安全（GRAS）的化合物，是对红色外来入侵红火蚁、黑色外来入侵红火蚁及其杂交种最有效的驱避剂，最低驱避有效剂量（MREDs）分别为0.98微克/克、7.80微克/克和0.98微克/克。百里香酚也表现出很强的驱避性，MREDs分别为31.25微克/克、31.25微克/克和7.8微克/克。此外，以含有48.8%百里香酚和5.1%香芹酚的百里香酚化学型为特征的百里香红色精油，被发现能有效驱避杂交蚁，MRED为15.6微克/克。相比之下，以缺乏百里香酚和香芹酚的芳樟醇化学型为特征的百里香精油，即使在最高测试剂量125微克/克时也未表现出任何驱避效果。本研究首次提供了香芹酚和百里香酚对进口红火蚁工蚁具有强效驱避性的证据，表明它们作为红火蚁防治有前景的驱避剂的潜力。
