Efficacy of water- and oil-in-water-formulated Metarhizium anisopliae in Rhipicephalus sanguineus eggs and eclosing larvae

Abstract

Conidia of the entomopathogenic fungus Metarhizium anisopliae (Ascomycota: Clavicipitaceae) were assessed against Rhipicephalus sanguineus (Arachnida: Ixodidae) eggs under laboratory conditions. Clusters of 25 eggs were applied either directly with the fungal conidial formulations or set on previously fungus-treated filter paper. Treatments consisted of conidia formulated in water or an oil-in-water emulsion at final concentrations of 3.3 × 10(3), 10(4), 3.3 × 10(4), 10(5), or 3.3 × 10(5) conidia/cm(2). The development of mycelium and new conidia on egg clusters incubated at 25 °C and humidity close to saturation depended on conidial concentration, formulation, and application technique. No larvae eclosed from eggs after direct applications of conidia regardless of the formulation. The eclosion and survival of larvae from indirectly treated egg clusters depended on the type of formulation and conidial concentration applied. Oil-in-water formulations of conidia demonstrated the highest activity against eggs of R. sanguineus.

Ovicidal Efficacy of Metarhizium anisopliae (Hypocreales: Clavicipitaceae) towards Rhipicephalus sanguineus (Acari: Ixodidae) Eggs

“…The difference might due to a higher conidial concentration increased the distribution of conidia on all eggs. This eventually enabled mycelium and conidia developed simultaneously on a high proportion of eggs and thus reduced the time of fungal development and increased the overall ovicidal activity (Luz et al, 2016). The LC 50 and LC 90 of this study corresponded with Luz et al (2016), however, zero larvae eclosed from clustered eggs treated were not achieved in this study with the concentration of 10 5 conidia mL -1 .…”

“…This eventually enabled mycelium and conidia developed simultaneously on a high proportion of eggs and thus reduced the time of fungal development and increased the overall ovicidal activity (Luz et al, 2016). The LC 50 and LC 90 of this study corresponded with Luz et al (2016), however, zero larvae eclosed from clustered eggs treated were not achieved in this study with the concentration of 10 5 conidia mL -1 . The reason might be due to uneven distribution of conidia on the eggs cluster when the lower concentration was used; it was then reduced the efficiency of the conidia.…”

First report of amitraz and cypermethrin resistance in Rhipicephalus sanguineus sensu lato infesting dogs in Mexico

“…This epidemiological knowledge may contribute to the development of effective integrated control strategies against populations that have already developed pyrethroid resistance, such as strategies that involve the rotation of products containing acaricides with other modes of action (i.e. insect growth regulators, macrocyclic lactones and alternative control methods such as biological control) (Ojeda‐Chi et al , ; Luz et al , ). An integrated tick control system that involves the education of veterinary staff and pet owners on tick biology, community involvement whereby owners are instructed on the proper use of mechanical control systems, and the dispensing of products that provide effective tick adulticide and environmental life stage control will help mitigate the impact of the brown dog tick on animal and human health (Pérez de León et al , ).…”

Advances in >i<Metarhizium>/i< blastospores production and formulation and transcriptome studies of the yeast and filamentous growth

“…The most common conidia-based formulations of Metahrizium are wettable powder, with the advantage of being a product ready to be added directly to water Agrofit, 2019) and granulated formulations (mainly sold as sporulated fungus in rice) (Agrofit 2019). Although there is no oil formulations of either blastospores or conidia of Metarhizium in the market (Agrofit 2019), the latter has been shown to be quite promising due to its greater protection against conidia desiccation, UV rays, high temperatures, better adhesion to arthropod hydrophobic cuticle and better target pest controls (Barreto et al ., 2016;Camargo et al, 2014;Samish et al, 2014;Luz et al, 2016). There is no blastospore oil formulation in the world market and only one publication related an attempt to formulate Cordyceps fumosoroseae (formerly Isaria fumosoroseae) blastospores (Kim et al, 2013).…”