Fernández-Salas Agustín, Romero-Pérez Juan Bernardo, Alonso-Díaz Miguel Ángel
Centro de Enseñanza, Investigación, y Extensión en Ganadería Tropical, Facultad de Medicina Veterinaria y Zootecnia, Universidad, Nacional Autónoma de México, CDMX, México.
Escuela de Medicina Veterinaria y Zootecnia, Universidad de Xicotepetl A.C., Puebla, México.
Exp Appl Acarol. 2025 Jan 30;94(2):34. doi: 10.1007/s10493-025-01003-z.
Entomopathogenic fungi (EPF) is one of the most promising alternatives to regulate tick populations. However, these fungi may lose acaricidal effectiveness over time, due to the storage period and/or successive cultivation on artificial media. It is known that using arthropod pests as a substrate for EPF could potentially alter their acaricidal behavior over time, however, studies using ticks for this purpose are scarce. Hence, the aims of this research were: (1) to isolate strains of Metarhizium anisopliae from paddocks of cattle farms, (2) to evaluate the effect of engorged adult ticks of Rhipicephalus microplus as a substrate on the tickicide behavior of Metarhizium anisopliae strains, and (3) to determine the lethal time of each M. anisopliae strain to kill 50% (LT50) and 99% (LT99) of engorged ticks. First, the natural acaricidal effect of 10 strains of M. anisopliae sensu lato isolated from soils of cattle farms on R. microplus was evaluated. Second, the influence of substrate (R. microplus, Galleria mellonella and Sabouraud dextrose agar [SDA]) on the acaricidal activity and virulence index (lethal time) of each strain during four generations was evaluated. Strains MaV69, MaV60 and MaV67 showed more than 90% mortality at day 20 post-treatment. The use of engorged adult ticks as substrate increased the virulence of five M. anisopliae s.l. strains. Larvae of G. mellonella and SDA as substrate did not modify the acaricidal behavior of the 10 strains evaluated. Seven of ten EPF decreased their LT50 and three decreased their LT99 as an index of their virulence enhancement.
昆虫病原真菌（EPF）是调控蜱虫种群最有前景的替代方法之一。然而，由于储存期和/或在人工培养基上连续培养，这些真菌的杀螨效力可能会随时间丧失。已知将节肢动物害虫用作EPF的底物可能会随着时间推移改变其杀螨行为，然而，为此目的使用蜱虫的研究很少。因此，本研究的目的是：（1）从养牛场围场中分离出绿僵菌菌株，（2）评估饱血的微小扇头蜱成虫作为底物对绿僵菌菌株杀螨行为的影响，以及（3）确定每种绿僵菌菌株杀死50%（LT50）和99%（LT99）饱血蜱虫的致死时间。首先，评估了从养牛场土壤中分离出的10株广义绿僵菌对微小扇头蜱的自然杀螨效果。其次，评估了底物（微小扇头蜱、大蜡螟和沙氏葡萄糖琼脂[SDA]）对四代培养过程中各菌株杀螨活性和毒力指数（致死时间）的影响。菌株MaV69、MaV60和MaV67在处理后第20天的死亡率超过90%。使用饱血的成年蜱作为底物提高了5株广义绿僵菌菌株的毒力。以大蜡螟幼虫和SDA作为底物并未改变所评估的10株菌株的杀螨行为。作为毒力增强指标，10株EPF中有7株的LT50降低，3株的LT99降低。
