USDA-ARS Cattle Fever Tick Research Laboratory, 22675 North Moorefield Rd., MAB 6419, Edinburg, TX, 78541, United States.
USDA-ARS Cattle Fever Tick Research Laboratory, 22675 North Moorefield Rd., MAB 6419, Edinburg, TX, 78541, United States.
Ticks Tick Borne Dis. 2021 Jul;12(4):101721. doi: 10.1016/j.ttbdis.2021.101721. Epub 2021 Apr 3.
Ectoparasitism result in annual losses to livestock producers estimated to reach billions of dollars in tropical and subtropical parts of the world where the southern cattle tick, Rhipicephalus (Boophilus) microplus, is established because this invasive pest is also a vector of pathogens causing bovine babesiosis and anaplasmosis. Reintroduction of R. microplus could be economically devastating for the cattle industry in the United States. Novel technologies are necessary to manage populations of R. microplus that are resistant to multiple classes of synthetic chemicals widely used as acaricides to control ticks infesting livestock, and to mitigate the environmental impact of these synthetic acaricides. Bioassays with a water-based formulation of a commercially available botanical acaricide (Essentria® IC3) at 6.25 % against a laboratory strain of R. microplus was 100 % lethal against unfed larvae, and 94 % mortality was recorded against engorged female ticks. These results prompted documentation of efficacy on infested cattle using an acaricide delivery system mimicking field conditions, which is required to consider the use of a product by integrated tick management programs. Twelve tick naïve cattle were artificially infested with unfed larvae on days -19, -12 and -5. On day -2, ticks from the left-side of the body of each animal were manually counted. Depending on pre-treatment tick counts the animals were assigned into three separate treatment groups: i) water (untreated control); ii) coumaphos 0.3 % in water (positive control); and iii) botanical acaricide 6.25 % in water. Five days after the last infestation, cattle were doused in a spray box and moved to individual stalls to collect tick data for calculation of treatment efficacy. The percentage control, based on the reproduction of surviving engorged female ticks after treatment with the 6.25 % Essentria in water-based spray was 70 % against R. microplus. Coumaphos treatment had a mean percent control of 100 %. Whereas this application of Essentria® IC3 cannot be recommended as a stand-alone method to eradicate R. microplus, the 6.25 % botanical acaricide water-based spray could be part of integrated tick management to control populations of R. microplus resistant to organophosphates like coumaphos and other classes of commercially available synthetic acaricides.
体外寄生虫导致每年给世界热带和亚热带地区的畜牧业生产者造成的损失估计达数十亿美元，因为在这些地区，南方牛蜱，即 Rhipicephalus (Boophilus) microplus 已经建立了种群。这种入侵性害虫也是引起牛巴贝斯虫病和无形体病的病原体的传播媒介。R. microplus 的重新引入可能会给美国的养牛业带来经济上的毁灭性打击。有必要采用新技术来管理对广泛用于控制寄生在牲畜身上的蜱的合成化学药剂的多类药剂产生抗药性的 R. microplus 种群，并减轻这些合成杀螨剂对环境的影响。采用水基配方的市售植物源杀螨剂（Essentria® IC3）对实验室饲养的 R. microplus 进行的生物测定显示，对未进食的幼虫的致死率为 100%，对饱食的雌性蜱的死亡率为 94%。这些结果促使我们采用一种模拟田间条件的杀螨剂输送系统，对受感染的牛进行功效记录，这是综合蜱管理计划考虑使用产品所必需的。将 12 头对蜱无经验的牛在-19、-12 和-5 天人工感染未进食的幼虫。在第-2 天，用手从每只动物身体的左侧数出蜱的数量。根据预处理蜱的数量，将动物分为三组：i）水（未处理对照）；ii）水合氯醛 0.3%（阳性对照）；和 iii）水基 6.25%植物源杀螨剂。在最后一次感染后 5 天，将牛放入喷雾箱中浸湿，然后转移到单独的畜栏中，收集蜱的数据以计算治疗效果。基于用 6.25% Essentria 处理后存活的饱食雌性蜱的繁殖情况，水中喷雾对 R. microplus 的防治效果为 70%。水合氯醛处理的平均防治率为 100%。尽管这种应用 Essentria® IC3 不能作为单独的根除 R. microplus 的方法，但 6.25%植物源杀螨剂水基喷雾可以作为综合蜱管理的一部分，用于控制对水合氯醛和其他市售合成杀螨剂类别的药剂产生抗药性的 R. microplus 种群。
