Discovery of Novel Entomopathogenic Fungi for Mosquito-Borne Disease Control

The increased application of chemical control programs has led to the emergence and spread of insecticide resistance in mosquitoes. Novel environmentally safe control strategies are currently needed for the control of disease vectors. The use of entomopathogenic fungi could be a suitable alternative to chemical insecticides. Currently, Beauveria spp. and Metarhizium spp. are the most widely used entomopathogenic fungi for mosquito control, but increasing the arsenal with additional fungi is necessary to mitigate the emergence of resistance. Entomopathogenic fungi are distributed in a wide range of habitats. We have performed a comprehensive screen for candidate mosquitocidal fungi from diverse outdoor environments in Maryland and Puerto Rico. An initial screening of 22 fungi involving exposure of adult Anopheles gambiae to 2-weeks-old fungal cultures identified five potent pathogenic fungi, one of which is unidentified and the remaining four belonging to the three genera Galactomyces sp., Isaria sp. and Mucor sp. These fungi were then screened against Aedes aegypti, revealing Isaria sp. as a potent mosquito killer. The entomopathogenic effects were confirmed through spore-dipping assays. We also probed further into the killing mechanisms of these fungi and investigated whether the mosquitocidal activities were the result of potential toxic fungus-produced metabolites. Preliminary assays involving the exposure of mosquitoes to sterile filtered fungal liquid cultures showed that Galactomyces sp., Isaria sp. and the unidentified isolate 1 were the strongest producers of factors showing lethality against An. gambiae. We have identified five fungi that was pathogenic for An. gambiae and one for Ae. aegypti, among these fungi, four of them (two strains of Galactomyces sp., Mucor sp., and the unidentified isolate 1) have never previously been described as lethal to insects. Further characterization of these entomopathogenic fungi and their metabolites needs to be done to confirm their potential use in biologic control against mosquitoes.

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Mosquito Control Priorities in Florida—Survey Results from Florida Mosquito Control Districts

Pathogens ◽

10.3390/pathogens10080947 ◽

2021 ◽

Vol 10 (8) ◽

pp. 947

Author(s):

Rishi Kondapaneni ◽

Ashley N. Malcolm ◽

Brian M. Vazquez ◽

Eric Zeng ◽

Tse-Yu Chen ◽

...

Keyword(s):

State Government ◽

Mosquito Control ◽

Control Strategies ◽

Mosquito Species ◽

Research Priorities ◽

Current Control ◽

Control Programs ◽

Common Control ◽

Surveillance Programs ◽

Research Questions

Florida lies within a subtropical region where the climate allows diverse mosquito species including invasive species to thrive year-round. As of 2021, there are currently 66 state-approved Florida Mosquito Control Districts, which are major stakeholders for Florida public universities engaged in mosquito research. Florida is one of the few states with extensive organized mosquito control programs. The Florida State Government and Florida Mosquito Control Districts have long histories of collaboration with research institutions. During fall 2020, we carried out a survey to collect baseline data on the current control priorities from Florida Mosquito Control Districts relating to (1) priority control species, (2) common adult and larval control methods, and (3) major research questions to address that will improve their control and surveillance programs. The survey data showed that a total of 17 distinct mosquito species were considered to be priority control targets, with many of these species being understudied. The most common control approaches included truck-mounted ultra-low-volume adulticiding and biopesticide-based larviciding. The districts held interest in diverse research questions, with many prioritizing studies on basic science questions to help develop evidence-based control strategies. Our data highlight the fact that mosquito control approaches and priorities differ greatly between districts and provide an important point of comparison for other regions investing in mosquito control, particularly those with similar ecological settings, and great diversity of potential mosquito vectors, such as in Florida. Our findings highlight a need for greater alignment of research priorities between mosquito control and mosquito research. In particular, we note a need to prioritize filling knowledge gaps relating to understudied mosquito species that have been implicated in arbovirus transmission.

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Bacterial Toxins Active against Mosquitoes: Mode of Action and Resistance

Toxins ◽

10.3390/toxins13080523 ◽

2021 ◽

Vol 13 (8) ◽

pp. 523

Author(s):

Maria Helena Neves Lobo Silva-Filha ◽

Tatiany Patricia Romão ◽

Tatiana Maria Teodoro Rezende ◽

Karine da Silva Carvalho ◽

Heverly Suzany Gouveia de Menezes ◽

...

Keyword(s):

Mode Of Action ◽

Mosquito Control ◽

Binary Toxin ◽

Lysinibacillus Sphaericus ◽

Control Programs ◽

Resistance Selection ◽

Single Receptor ◽

Combined Use ◽

Environmentally Safe ◽

Medical Importance

Larvicides based on the bacteria Bacillus thuringiensis svar. israelensis (Bti) and Lysinibacillus sphaericus are effective and environmentally safe compounds for the control of dipteran insects of medical importance. They produce crystals that display specific and potent insecticidal activity against larvae. Bti crystals are composed of multiple protoxins: three from the three-domain Cry type family, which bind to different cell receptors in the midgut, and one cytolytic (Cyt1Aa) protoxin that can insert itself into the cell membrane and act as surrogate receptor of the Cry toxins. Together, those toxins display a complex mode of action that shows a low risk of resistance selection. L. sphaericus crystals contain one major binary toxin that display an outstanding persistence in field conditions, which is superior to Bti. However, the action of the Bin toxin based on its interaction with a single receptor is vulnerable for resistance selection in insects. In this review we present the most recent data on the mode of action and synergism of these toxins, resistance issues, and examples of their use worldwide. Data reported in recent years improved our understanding of the mechanism of action of these toxins, showed that their combined use can enhance their activity and counteract resistance, and reinforced their relevance for mosquito control programs in the future years.

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Amino Acids in Entomopathogenic Fungi Cultured In Vitro

Agronomy ◽

10.3390/agronomy10121899 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1899

Author(s):

Lech Wojciech Szajdak ◽

Stanisław Bałazy ◽

Teresa Meysner

Keyword(s):

Amino Acids ◽

Entomopathogenic Fungi ◽

Pathogenic Fungi ◽

Individual Species ◽

Conidiobolus Coronatus ◽

Fungal Strains ◽

Isaria Farinosa ◽

Lecanicillium Lecanii ◽

Wide Range

The content of bounded amino acids in six entomopathogenic fungi was identified and determined. Analyzing the elements characterizing the pathogenicity of individual species of fungi based on infectivity criteria, ranges of infected hosts, and the ability to induce epizootics, these can be ranked in the following order: Isaria farinosa, Isaria tenuipes, Isaria fumosorose, Lecanicillium lecanii, Conidiobolus coronatus, Isaria coleopterorum. These fungi represent two types of Hyphomycetales-Paecilomyces Bainier and Verticillium Nees ex Fr. and one type of Entomophtorales-Conidiobolus Brefeld. Our study indicates that there are significant quantitative and qualitative differences of bounded amino acids in the entomopathogenic fungal strains contained in the mycelium between high and low pathogenicity strains. The richest composition of bounded amino acids has been shown in the mycelium of the Isaria farinosa strain, which is one of the most commonly presented pathogenic fungi in this group with a very wide range of infected hosts and is the most frequently recorded in nature as an important factor limiting the population of insects.

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Biological control of Drosophila suzukii.

CAB Reviews Perspectives in Agriculture Veterinary Science Nutrition and Natural Resources ◽

10.1079/pavsnnr202015054 ◽

2020 ◽

Vol 15 (054) ◽

Author(s):

Xing-eng Wang

Keyword(s):

Biological Control ◽

Natural Enemies ◽

Control Strategies ◽

Pathogenic Fungi ◽

Classical Biological Control ◽

Research Progress ◽

Drosophila Suzukii ◽

Control Programs ◽

Crop Fields ◽

Indigenous Natural Enemies

Abstract Drosophila suzukii (Matsumura) is native to East Asia but has widely established in the Americas and Europe, where it is a devastating pest of soft-skinned fruits. It has a wide host range and these non-crop habitats harbor the fly which then repeatedly reinvades crop fields. Biological control in non-crop habitats could be the cornerstone for sustainable management at the landscape level. Toward this goal, researchers have developed or investigated biological control tactics. We review over 100 studies, conducted in the Americas, Asia and Europe on natural enemies of D. suzukii. Two previous reviews provided an overview of potential natural enemies and detailed accounts on foreign explorations. Here, we provide an up-to-date list of known or evaluated parasitoids, predators and entomopathogens (pathogenic fungi, bacteria, nematodes, and viruses) and summarize research progress to date. We emphasize a systematic approach toward the development of biological control strategies that can stand alone or be combined with more conventional control tools. Finally, we propose a framework for the integrated use of biological control tools, from classical biological control with host-specific Asian parasitoids, to augmentative and conservation biological control with indigenous natural enemies, to the use of entomopathogens. This review provides a roadmap to foster the use of biological control tools in more sustainable D. suzukii control programs.

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Identification of Entomopathogenic Fungi as Naturally Occurring Enemies of the Invasive Oak Lace Bug, Corythucha arcuata (Say) (Hemiptera: Tingidae)

Insects ◽

10.3390/insects11100679 ◽

2020 ◽

Vol 11 (10) ◽

pp. 679

Author(s):

Marta Kovač ◽

Michał Gorczak ◽

Marta Wrzosek ◽

Cezary Tkaczuk ◽

Milan Pernek

Keyword(s):

Entomopathogenic Fungi ◽

Natural Enemies ◽

Control Strategies ◽

Pathogenic Fungi ◽

Rapid Expansion ◽

Invasive Pest ◽

Pedunculate Oak ◽

Lace Bug ◽

Naturally Occurring ◽

Forested Areas

The oak lace bug (OLB), Corythucha arcuata (Hemiptera: Tingidae), was first identified as an invasive pest in Europe in northern Italy in 2000 and since then it has spread rapidly, attacking large forested areas in European countries. The OLB is a cell sap-sucking insect that is native to North America, with Quercus spp. as its main host. Its rapid expansion, successful establishment in invaded countries, and observations of more damage to hosts compared to native areas are most likely due to a lack of natural enemies, pathogens and competitors. In its native area, various natural enemies of OLBs have been identified; however, little is known about the occurrence and impact of OLB pathogens. None of the pathogenic fungi found on OLBs in natural conditions have been identified until now. In this study, we provide evidence of four entomopathogenic fungi that are naturally occurring on invasive OLBs found in infested pedunculate oak forests in eastern Croatia. On the basis of their morphology and multilocus molecular phylogeny, the fungi were identified as Beauveria pseudobassiana, Lecanicillium pissodis, Akanthomyces attenuatus and Samsoniella alboaurantium. The sequences generated for this study are available from GenBank under the accession numbers MT004817-MT004820, MT004833-MT004835, MT027501-MT27510, and MT001936-MT0011943. These pathogenic species could facilitate biological control strategies against OLBs.

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Toxicological Evaluation of Novel Butenolide Pesticide Flupyradifurone Against Culex quinquefasciatus (Diptera: Culicidae) Mosquitoes

Journal of Medical Entomology ◽

10.1093/jme/tjaa118 ◽

2020 ◽

Vol 57 (6) ◽

pp. 1857-1863

Author(s):

Mohamed Ahmed Ibrahim Ahmed ◽

Christoph Franz Adam Vogel

Keyword(s):

Culex Quinquefasciatus ◽

Mosquito Control ◽

Control Strategies ◽

Synergetic Effect ◽

Fourth Instar ◽

Synergistic Action ◽

Toxicological Evaluation ◽

Control Programs ◽

Octopamine Receptor ◽

The Impact

Abstract The impact of increasing resistance of mosquitoes to conventional pesticides has led to investigate various unique tools and pest control strategies. Herein, we assessed the potency of flupyradifurone, a novel pesticide, on fourth instar larvae of Culex quinquefasciatus Say. Further, we evaluated the synergistic action of piperonyl butoxide (PBO) and the octopamine receptor agonists (OR agonists) chlordimeform (CDM) and amitraz (AMZ) on the toxicity of flupyradifurone in comparison with sulfoxaflor and nitenpyram to increase their toxicity on Cx. quinquefasciatus. Results demonstrated that flupyradifurone was the most potent pesticide followed by sulfoxaflor and nitenpyram. Further, the synergetic effect of PBO, CDM, and AMZ was significant for all selected pesticides especially flupyradifurone. However, AMZ had the most significant effect in combination with the selected pesticides followed by CDM and PBO. The toxicity of the pesticides was time-dependent and increased over time from 24, 48, to 72 h of exposure in all experiments. The results indicate that flupyradifurone is a promising component in future mosquito control programs.

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A Broad-Based Mosquito Yeast Interfering RNA Pesticide Targeting Rbfox1 Represses Notch Signaling and Kills Both Larvae and Adult Mosquitoes

Pathogens ◽

10.3390/pathogens10101251 ◽

2021 ◽

Vol 10 (10) ◽

pp. 1251

Author(s):

Keshava Mysore ◽

Longhua Sun ◽

Limb K. Hapairai ◽

Chien-Wei Wang ◽

Joseph B. Roethele ◽

...

Keyword(s):

Notch Signaling ◽

Mosquito Control ◽

Field Trials ◽

New Paradigm ◽

Control Programs ◽

Rnai Technology ◽

Impact On Survival ◽

Environmentally Safe ◽

Control Technologies ◽

Interfering Rna

Prevention of mosquito-borne infectious diseases will require new classes of environmentally safe insecticides and novel mosquito control technologies. Saccharomyces cerevisiae was engineered to express short hairpin RNA (shRNA) corresponding to mosquito Rbfox1 genes. The yeast induced target gene silencing, resulting in larval death that was observed in both laboratory and outdoor semi-field trials conducted on Aedes aegypti. High levels of mortality were also observed during simulated field trials in which adult females consumed yeast delivered through a sugar bait. Mortality correlated with defects in the mosquito brain, in which a role for Rbfox1 as a positive regulator of Notch signaling was identified. The larvicidal and adulticidal activities of the yeast were subsequently confirmed in trials conducted on Aedes albopictus, Anopheles gambiae, and Culex quinquefasciatus, yet the yeast had no impact on survival of select non-target arthropods. These studies indicate that yeast RNAi pesticides targeting Rbfox1 could be further developed as broad-based mosquito larvicides and adulticides for deployment in integrated biorational mosquito control programs. These findings also suggest that the species-specificity of attractive targeted sugar baits, a new paradigm for vector control, could potentially be enhanced through RNAi technology, and specifically through the use of yeast-based interfering RNA pesticides.

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Marine Organisms for the Sustainable Management of Plant Parasitic Nematodes

Plants ◽

10.3390/plants10020369 ◽

2021 ◽

Vol 10 (2) ◽

pp. 369

Author(s):

Pasqua Veronico ◽

Maria Teresa Melillo

Keyword(s):

Crop Production ◽

Control Strategies ◽

Marine Organisms ◽

New Drugs ◽

Effective Control ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Wide Range ◽

Plant Growth Stimulants ◽

Plant Parasitic

Plant parasitic nematodes are annually responsible for the loss of 10%–25% of worldwide crop production, most of which is attributable to root-knot nematodes (RKNs) that infest a wide range of agricultural crops throughout the world. Current nematode control tools are not enough to ensure the effective management of these parasites, mainly due to the severe restrictions imposed on the use of chemical pesticides. Therefore, it is important to discover new potential nematicidal sources that are suitable for the development of additional safe and effective control strategies. In the last few decades, there has been an explosion of information about the use of seaweeds as plant growth stimulants and potential nematicides. Novel bioactive compounds have been isolated from marine cyanobacteria and sponges in an effort to find their application outside marine ecosystems and in the discovery of new drugs. Their potential as antihelmintics could also be exploited to find applicability against plant parasitic nematodes. The present review focuses on the activity of marine organisms on RKNs and their potential application as safe nematicidal agents.

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Improving Contagion and Horizontal Transmission of Entomopathogenic Fungi by the White-Spotted Longicorn Beetle, Anoplophora malasiaca, with Help of Contact Sex Pheromone

Insects ◽

10.3390/insects12050383 ◽

2021 ◽

Vol 12 (5) ◽

pp. 383

Author(s):

Nao Fujiwara-Tsujii ◽

Hiroe Yasui

Keyword(s):

Sex Pheromone ◽

Entomopathogenic Fungi ◽

Horizontal Transmission ◽

Pathogenic Fungi ◽

Male Mating ◽

Contact Sex Pheromone ◽

Beauveria Brongniartii ◽

Contact Pheromone ◽

Horticultural Crops ◽

Longicorn Beetle

The white-spotted longicorn beetle, Anoplophora malasiaca, is one of the most destructive pests of horticultural crops and street trees. Effective controls are needed because the effect of marketed insecticides is limited. Entomopathogenic fungi offer a solution, and improving the rate of infection would be a breakthrough in this beetle’s control. The combination of pathogenic fungi and the beetle’s contact sex pheromone was suggested. The surface of the female body is covered with contact sex pheromone, which elicit male mating behavior. To develop a method for the practical control of this beetle, we evaluated the arrestant activity of female extract containing contact pheromone coated on a black glass model. Males presented with a coated model held on for 5 h (mean) during an 8-h experiment. In contrast, males presented with a control model held on for <0.3 h. Males that held onto coated models attached to fabric impregnated with conidia of the fungus Beauveria brongniartii picked up much conidia, which they then passed on to females during mating.

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Wolbachia: endosymbiont of onchocercid nematodes and their vectors

Parasites & Vectors ◽

10.1186/s13071-021-04742-1 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Ranju Ravindran Santhakumari Manoj ◽

Maria Stefania Latrofa ◽

Sara Epis ◽

Domenico Otranto

Keyword(s):

Control Strategies ◽

Molecular Data ◽

Scientific Data ◽

Growth And Survival ◽

Vector Borne Diseases ◽

Wide Range ◽

Veterinary Importance ◽

Wolbachia Endosymbiont ◽

Vector Borne ◽

And Control

Abstract Background Wolbachia is an obligate intracellular maternally transmitted, gram-negative bacterium which forms a spectrum of endosymbiotic relationships from parasitism to obligatory mutualism in a wide range of arthropods and onchocercid nematodes, respectively. In arthropods Wolbachia produces reproductive manipulations such as male killing, feminization, parthenogenesis and cytoplasmic incompatibility for its propagation and provides an additional fitness benefit for the host to protect against pathogens, whilst in onchocercid nematodes, apart from the mutual metabolic dependence, this bacterium is involved in moulting, embryogenesis, growth and survival of the host. Methods This review details the molecular data of Wolbachia and its effect on host biology, immunity, ecology and evolution, reproduction, endosymbiont-based treatment and control strategies exploited for filariasis. Relevant peer-reviewed scientic papers available in various authenticated scientific data bases were considered while writing the review. Conclusions The information presented provides an overview on Wolbachia biology and its use in the control and/or treatment of vectors, onchocercid nematodes and viral diseases of medical and veterinary importance. This offers the development of new approaches for the control of a variety of vector-borne diseases. Graphic Abstract

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