ABSTRACT The obligate ectoparasite Rhipicephalus (Boophilus) annulatus, also known as cattle tick, is the hard tick vector of babesiosis, a protozoal infection that causes severe meat production losses at huge economic costs. Although babesiosis was eradicated from the United States, its vector still exists in Mexico and different security measures are used to prevent its reintroduction into the U.S. Furthermore, the massive use of chemical acaricides during the last century has resulted in the development of resistance and toxicological problems. A possible and more sustainable alternative could be represented by the applications of biopesticides. Recently, two sesquiterpenoids, inuloxin A and α-costic acid isolated from Dittrichia viscosa, a perennial native plant of the Mediterranean basin, showed several interesting biological activities including acaricidal and antifeedant activities. Both inuloxin A and α-costic acid caused an impact on the hatch rate of the eggs and a larval mortality rate higher than 80% in vitro bioassays on eggs of R. annulatus. Moreover, the hatch rate of the eggs and the mortality rate of the larvae seem to be dependent on the timing of application of the compounds on the eggs. These results suggested a potential use of both compounds to control R. annulatus. GRAPHICAL ABSTRACT

中文翻译：

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植物倍半萜类化合物 α-costic acid 和 inuloxin A 对牛体外寄生蜱、Rhipicephalus (Boophilus) annulatus 的杀螨活性

摘要 专性外寄生虫 Rhipicephalus (Boophilus) annulatus，也称为牛蜱，是巴贝虫病的硬蜱载体，巴贝斯虫病是一种原虫感染，以巨大的经济成本导致严重的肉类生产损失。虽然巴贝斯虫病已从美国根除，但其媒介仍存在于墨西哥，并采取不同的安全措施防止其重新传入美国。此外，上个世纪化学杀螨剂的大量使用导致耐药性和毒理学问题的发展. 生物农药的应用可以代表一种可能且更可持续的替代方案。最近，从地中海盆地的多年生本土植物 Dittrichia viscosa 中分离出两种倍半萜类化合物菊糖素 A 和 α-木香酸，显示了几种有趣的生物活性，包括杀螨和拒食活性。inuloxin A 和 α-costic acid 均对卵的孵化率产生影响，并且在体外生物测定中对圆环红藻卵的幼虫死亡率高于 80%。此外，卵的孵化率和幼虫的死亡率似乎取决于在卵上施用化合物的时间。这些结果表明这两种化合物都有可能用于控制 R. annulatus。图形概要 卵的孵化率和幼虫的死亡率似乎取决于在卵上施用化合物的时间。这些结果表明这两种化合物都有可能用于控制 R. annulatus。图形概要 卵的孵化率和幼虫的死亡率似乎取决于在卵上施用化合物的时间。这些结果表明这两种化合物都有可能用于控制 R. annulatus。图形概要