Curso de Pós-Graduação em Ciências Veterinárias, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ 23890-000, Brazil.
Vet Parasitol. 2012 Aug 13;188(1-2):140-7. doi: 10.1016/j.vetpar.2012.03.012. Epub 2012 Mar 16.
The formulations of acaripathogenic fungi to control ticks have been widely studied. The present study evaluated the efficacy of oil-based formulations of Metarhizium anisopliae sensu lato (s.l.), isolate Ma 959, and Beauveria bassiana, isolate Bb 986, on different Rhipicephalus microplus stages, comparing the efficacy between aqueous suspensions and 10, 15 and 20% mineral oil formulations. Twelve groups were formed: one aqueous control group; three mineral oil control groups, at 10, 15 or 20%; two aqueous fungal suspensions of M. anisopliae s.l. or B. bassiana; and three formulations of M. anisopliae (s.l.) or B. bassiana containing 10, 15, and 20% mineral oil. To prepare aqueous suspensions and oily formulations, fungal isolates were cultivated on rice grains in polypropylene bags. The conidial suspensions and formulations had a concentration of 10(8)conidia/mL. Bioassays were repeated twice. After treatment, the following biological parameters of engorged females were evaluated: hatching percentage, egg production index, nutritional index, and percentage of tick control. The following parameters were evaluated in the bioassays with eggs: period of incubation, period of hatch, and hatching percentage. Mortality was evaluated in bioassays with larvae. M. anisopliae s.l. and B. bassiana oil-based formulations were more effective than aqueous suspensions against R. microplus eggs, larvae and engorged females, however, there was no significant difference between the three oil concentrations used. M. anisopliae s.l. and B. bassiana formulated in mineral oil reached 93.69% and 21.67% efficacy, respectively, while M. anisopliae s.l. and B. bassiana aqueous suspensions attained 18.70% and 1.72% efficacy, respectively. M. anisopliae s.l. oil-based formulations caused significant effects in all biological parameters of engorged females while B. bassiana oil-based formulations modified significantly the nutritional index only. Eggs treated with M. anisopliae s.l. and B. bassiana oil-based formulations showed hatching rates that decreased 102.5 and 3.65 times, respectively. In the bioassay with larvae, M. anisopliae s.l. oil-based formulations caused nearly 100% mortality five days after treatment, while larva treated with B. bassiana oil-based formulations reached 100% mortality at day 20 after treatment. Larva from oil-based control groups showed mortality at day 15 after treatment, which indicated a possible toxic effect of the oil for this R. microplus stage. The results showed that the fungal mineral oil formulations tested were more effective than the aqueous suspension. Oil-based formulations at 10, 15 and 20% enhanced the activity of M. anisopliae s.l. Ma 959, and B. bassiana Bb 986, isolates against R. microplus eggs, larvae, and engorged females tick. Mineral oil was effective as an adjuvant in formulations of M. anisopliae s.l., Ma 959, and B. bassiana, Bb 986, for the control of R. microplus under laboratory conditions.
杀蜱真菌制剂已被广泛研究用于控制蜱。本研究评估了不同阶段的硬蜱（Rhipicephalus microplus）对厚垣轮枝菌（Metarhizium anisopliae sensu lato）（简称 Ma 959）和球孢白僵菌（Beauveria bassiana），简称 Bb 986）油基制剂的效果，比较了水悬浮液和 10%、15%和 20%矿物油制剂之间的效果。形成了 12 个组：一个水对照；三个矿物油对照，浓度分别为 10%、15%和 20%；两种水悬浮液 M. anisopliae s.l. 或 B. bassiana；以及三种 M. anisopliae（s.l.）或 B. bassiana 制剂，分别含有 10%、15%和 20%的矿物油。为了制备水悬浮液和油性制剂，真菌分离物在聚丙烯袋中的稻谷上培养。菌悬液和制剂的浓度为 10(8)conidia/mL。生物测定重复了两次。处理后，评估以下饱血雌蜱的生物学参数：孵化率、产卵指数、营养指数和蜱控制率。评估卵的生物测定中还评估了孵化期、孵化期和孵化率。幼虫的生物测定评估死亡率。与水悬浮液相比，厚垣轮枝菌 s.l. 和球孢白僵菌油基制剂对硬蜱卵、幼虫和饱血雌蜱更有效，但使用的三种油浓度之间没有显著差异。厚垣轮枝菌 s.l. 和球孢白僵菌在矿物油中的制剂分别达到 93.69%和 21.67%的功效，而厚垣轮枝菌 s.l. 和球孢白僵菌水悬浮液的功效分别为 18.70%和 1.72%。厚垣轮枝菌 s.l. 油基制剂对饱血雌蜱的所有生物学参数均有显著影响，而球孢白僵菌油基制剂仅显著改变了营养指数。用厚垣轮枝菌 s.l. 和球孢白僵菌油基制剂处理的卵显示孵化率分别降低了 102.5 和 3.65 倍。在幼虫生物测定中，厚垣轮枝菌 s.l. 油基制剂在处理后五天内引起近 100%的死亡率，而用球孢白僵菌油基制剂处理的幼虫在处理后 20 天达到 100%的死亡率。用 B. bassiana 油基制剂处理的幼虫在处理后第 15 天出现死亡，这表明油对该 R. microplus 阶段可能有毒性作用。结果表明，与水悬浮液相比，测试的真菌矿物油制剂更有效。10%、15%和 20%的油基制剂增强了厚垣轮枝菌 s.l. Ma 959 和球孢白僵菌 Bb 986 分离物对硬蜱卵、幼虫和饱血雌蜱的活性。矿物油在厚垣轮枝菌 s.l. Ma 959 和球孢白僵菌 Bb 986 的制剂中作为佐剂有效，用于控制实验室条件下的 R. microplus。
