In vitro efficacy of two commercial products of Metarhizium anisopliae s.l. for controlling the cattle tick Rhipicephalus microplus

Abstract

<jats:p>Abstract The effects of two different products - Metarril® SP Organic (dry conidia) and Metarril® SC Organic (emulsifiable concentrated conidia in vegetable oil) - on eggs, larvae and Rhipicephalus microplus engorged females were here explored. Three concentrations (108, 107, and 106 conidia mL-1) for both products were prepared in water + 0.1% Tween® 80 (v/v); afterward, bioassays were carried out for all R. microplus stages by immersion in suspensions (Metarril® SP) or formulations (Metarril® SC). Metarril® SP suspensions showed low efficacy and did not affect biological parameters of treated engorged females; for eggs and larvae, only slight decreases in hatchability and larvae population were observed. Despite a delay in germination, Metarril® SC presented better results; for females, reductions in Egg Mass Weight (EMW) and Egg Production Index (EPI) were reported. On eggs, 108 conidia mL-1 increased Incubation Period (IP), shortened Hatching Period (HP) and decreased hatchability by up to 61%; for larvae, 107 and 108 conidia mL-1 reached 99.6 and 100% larval mortality respectively, 10 days after fungal exposure. Thus, further studies involving the use of oil-based formulations for ticks such as Metarril® SC need to be performed, especially to control the most susceptible stages (eggs and larvae).</jats:p>

Potential of Two &lt;i&gt;Metarhizium anisopliae&lt;/i&gt; (Clavicipitaceae) Isolates for Biological Control of &lt;i&gt;Diatraea saccharalis&lt;/i&gt; (Lepidoptera: Crambidae) Eggs

“…Similar results were observed with different isolates of M. anisopliae in the control of arachnids [35] [36] [37], nematodes [38], and lepidopterans [33]. Infection by M. anisopliae starts passively and is related to hydrophobic interactions [39].…”

Entomopathogenic Fungi and Bacteria in a Veterinary Perspective

“…The mold acted as active, along with B. bassiana [131] as well as a blastospore suspension, together with B. bassiana and M. robertsii [132]. R. microplus was sensitive to commercial conidial suspensions in vegetable oils [133] and both in vegetal and mineral oils, applied on the grass, killing 100% of ticks and lasting in the environment up to 60 days [134]. A similar good efficacy against R. microplus was reported for a formulation containing both microsclerotia and blastospores of M. robertsii [135].…”

“…[193] Rhipicephalus appendiculatus Fusarium sp. [193] Rhipicephalus appendiculatus Metarhizium anisopliae [151,152,193] Rhipicephalus appendiculatus Beauveria bassiana [151] Rhipicephalus appendiculatus M. anisopliae + B. bassiana [152] Rhipicephalus decoloratus Beauveria bassiana [150] Rhipicephalus microplus Metarhizium robertsii [126,127,132,135] Rhipicephalus microplus Beauveria bassiana [129,132,145,146,155,[158][159][160] Rhipicephalus microplus Metarhizium anisopliae [129,132,133,155,[158][159][160] Rhipicephalus microplus Paecilomyces lilacinus [129] Rhipicephalus microplus Isaria fumosorosea [162] Table 1. Cont.…”