The potential of integrating the mycoinsecticide, Metarhizium anisopliae (Met.), into house fly control programs is tremendous. However, the interaction between the fungus and insecticide, when applied at poultry farms, remains poorly understood. This study investigated the interaction between M. anisopliae and two selected insecticides, cyromazine and ChCy (a mixture of chlorpyrifos and cypemethrin), with three objectives: to assess the compatibility of M. anisopliae and the insecticides by measuring fungal vegetative growth and conidia production in the presence of insecticides; to evaluate the effect of M. anisopliae on these insecticides by analyzing insecticidal residue using ultra performance liquid chromatography; and to study the synergistic effects of M. anisopliae and the insecticides by applying sublethal concentrations of insecticides with M. anisopliae to house fly larvae. Metarhizium anisopliae was more tolerant to ChCy than to cyromazine, as M. anisopliae showed significantly more growth when grown with this insecticide. The M. anisopliae + ChCy combination resulted in significantly less chlorpyrifos residues compared to the ChCy plate, and 62-72% house fly larva mortality occurred when M. anisopliae and sublethal concentrations of ChCy were combined, implicating synergistic effects of the fungus with low concentrations of ChCy. Integrating M. anisopliae with compatible chemical at right concentration is crucial for poultry farm house fly control programs.
Metarhizium anisopliae Metchnikoff (Hypocreales: Clavicipitaceae) is a fungal pathogen that causes disease in various insect pests, and it can be exploited and developed as a biological control agent to combat the red palm weevil, Rhynchophorus ferrugineus Olivier (Coleoptera: Dryophthoridae). The study on indigenous isolates is crucial especially for development of bioinsecticides in the future. The M. anisopliae strain called MET-GRA4 was tested for pathogenicity against adult red palm weevil and treated in vitro with different spore viabilities. The isolates exhibited pathogenicity with 100% mortality 21 d postinfection. The median lethal time (LT50) for 85% viable spores was 8.6 d, while 39% viable spores had an LT50 value of 21.37 d, with 92 and 16.6% mycosis, respectively. The species MET-GRA4 strain was molecularly characterized using ITS1 and ITS4 from pure culture (Isolate A), mass-produced spores (Isolate B), and infected red palm weevil cadavers (Isolate C). The DNA sequences obtained matched M. anisopliae sequences, with 99% similarity. This new isolate of M. anisopliae has potential as a targeted bioinsecticide for management of red palm weevil.
Ticks exert a significant economic impact on the livestock industry, particularly in Asian regions. Presently, chemical acaricides constitute the primary method employed to combat tick infestations in livestock, but their use carries adverse environmental consequences. Overreliance on acaricides has contaminated milk and meat products with chemical residues while fostering tick resistance to these agents due to improper and intensive application. Various alternative methods have been explored, including using vaccines to manage tick populations. However, the efficacy of these treatments varies and is often limited when applied separately. Among these alternatives, entomopathogenic fungi like Metarhizium anisopliae appear to be a promising candidate for tick population control. This fungus can be used independently and in conjunction with other products. This review article explores the current and future prospects of M. anisopliae, where the existing gaps and future directives for using this fungus to control hard ticks in Asian countries are highlighted.
Plant pathogens with their abundance are harmful and cause huge damage to different agricultural crops and economy of a country as well as lead towards the shortage of food for humans. For their management, the utilization of entomopathogenic fungi is an eco-friendly technique, sustainable to the environment, safe for humans and has promising effect over chemical-based pesticides. This process requires a biochemical mechanism, including the production of enzymes, toxins, and other metabolites that facilitate host infection and invasion. Essential enzymes such as chitinase, proteinase, and lipase play a direct role in breaking down the host cuticle, the primary barrier to EPF (Entomopathogenic Fungi) infection. Additionally, secondary metabolites such as destruxins in Metarhizium, beauvericin in Beauveria, hirsutellides in Hirsutella, isarolides in Isaria, cordyols in Cordyceps, and vertihemipterins in Verticillium, among others, act both directly and indirectly to disable the defense mechanisms of insect hosts, thereby accelerating the EPF infection process. The chemical composition of these secondary metabolites varies, ranging from simple non-peptide pigments such as oosporine to highly complex piperazine derivatives such as vertihemiptellides. The biocontrol efficacy of EPF is extensively studied, with numerous fungal strains commercially available on a large scale for managing arthropod pests. This review emphasizes the role of proteins and enzymes against crop pathogens, detailing their mode of action, and describing the metabolites from entomopathogenic fungi and their biological activities. In doing so, these findings contribute to establishing a symbiotic equilibrium between agricultural productivity and environmental conservation.
Red palm weevil (RPW), Rhynchophorus ferrugineus, is a polyphagous insect that caused economic damage in various palm species, particularly coconut plantation in Malaysia. Therefore, entomopathogenic fungus Metarhizium anisopliae was being introduced in attempts to control biologically the RPW. The entomopathogenicity of an indigenous (Met-Gra4) and foreign (Met-TH) strains of M. anisopliae isolated from the soil of Malaysia and Thailand, were tested against RPW adults in laboratory bioassays at 50, 70, 90% relative humidity (RH). Bioassays indicate no significance differences in efficacy between both the conidia of M. anisopliae strains against RPW adults. Met-Gra4 showed the highest efficacy at 90% RH (LT50 = 6.17 days). However, LT50 only slightly differed from Met-TH (6.33 days; 90% RH). Scanning el ectron microscopy for the treated RPWs showed that Met-Gra4 (90% RH) was densely sporulated within the abdomen, while Met-TH can be found mainly across cuticular surface of RPW.
Metarhizium anisopliae (Metchnikoff) Sorokin, a pathogenic fungus to insects, infects the subterranean termite, Coptotermes curvignathus Holmgren, a devastating pest of plantation trees in the tropics. Electron microscopy and proteomics were used to investigate the infection and developmental process of M. anisopliae in C. curvignathus. Fungal infection was initiated by germ tube penetration through the host's cuticle as observed at 6 h post-inoculation (PI), after which it elongated into the host's integumental tissue. The colonization process continued as seen from dissemination of blastospores in the hemocoel at 96 h PI. At this time point, the emergent mycelia had mummified the host and forty-eight hours later, new conidia were dispersed on the termites' body surface. Meanwhile, hyphal bodies were observed in abundance in the intercellular space in the host's body. The proteomes of the pathogen and host were isolated separately using inoculated termite samples withdrawn at each PI-time point and analyzed in two-dimensional electrophoresis (2-DE) gels. Proteins expressed in termites showed evidence of being related to cell regulation and the immune response, while those expressed in M. anisopliae, to transportation and fungal virulence. This study provides new information on the interaction between termites and its entomopathogen, with potential utilization for developing future biopesticide to control the termite population.