Entomopathogenic fungi have been widely studied for their potential as the effective biological control agents. They produce variety of secondary metabolites with insecticidal activities, and it is reasonable to assume that entomopathogenic fungi might produce secondary metabolites modulating juvenile hormone for their survival against defense mechanisms of host insect. In this study, acetone extract of the Lecanicillium spp. cultured on unpolished rice medium showed juvenile hormone antagonist (JHAN) activity in the yeast-two hybrid β-galactosidase assay and high insecticidal activity against Aedes albopictus and Plutella xylostella. In addition, to compare bioactivities of secondary metabolites from solid and liquid culture, the Lecaniciilium spp. strain cultured on unpolished rice medium or PDB medium were serially extracted with acetone and ethyl acetate respectively. Both extracts showed JHAN activity and high insecticidal activity against A.albopictus. Theses results suggested that secondary metabolites of entomopathogenic fungi could be useful for development of novel IGR insecticides.

Entomopathogenic fungi are expected to play a role as great biological control agents in the global bio-pesticide market in the future. The first step is the collection of fungal isolates and it should be a platform for the development of highly effective biopesticides. In this work, we constructed a fungal library using a mealworm pathogenecity-based fungal collection method and further characterized some isolates with high virulence. A phylogenetic tree was generated, and of the isolates 17 isolates’ biological features were characterized, such as morphology, virulence against several insect, stability of conidia for heat, production of biologically active materials, such as enzymes. This work reports an attractive entomopathogenic fungal library including the information of effective isolates in pest management.

Entomopathogenic fungi are potential pesticides as biological control agents. However, many previous studies have focused on basic researches to control pest using insect-pathogenic fungi. Herein, the molecular characteristics of insect defense mechanisms against fungal pathogens and fungal pathogenicity to insects were investigated. The whole genome of Beauveria bassiana (Bb) JEF-007 was sequenced (36,538,394 bp) using Pacbio sequencing. Based on this data, the transcriptomes of bean bug and fungus were analyzed using RNA-seq. In the transcriptome analyses, six and five genes were validated to be involved in the fungal pathogenicity and insect defense, respectively. This work can provide an understanding of the insect-pathogen interactions

Virulence of six entomopathogenic fungi was assessed against the 1st instar larva (<5 h old) of oriental fruit moth Grapholita molesta (Busck) in laboratory which is considered as an important pest for stone fruits. Three strains of Beauveria bassiana and each strain of Metarhizium robertsii, Metarhizium bruneum, and Isaria farinosa were evaluated with the concentration of 1×108 conidia/mL at 95.9% RH and 25.4°C by glass scintillation vial assay. Among all, two strains of B. bassiana, ARP14 (87.5%) and A (unpublished) (72.7%), showed highest virulence with 9.8 and 12.6 h of LT50 within 16 h of exposure. However, B. bassiana A showed highest infection rate of 90.0% compare to ARP14 (70.0%) after 14 days. From these results, the two strains of B. bassiana, ARP14 and A, can be used for the control of G. molesta.

The two-spotted spider mite, Tetranychus urticae, is one of the most important pests of crops. However, chemical acaricides are not always effective and their continuous use has resulted in resistance among two-spotted spider mite populations. To reduce or replace use of chemical acaricides, the entomopathogenic fungi having acaricidal activity were investigated. As results, 12 isolates could be selected from 342 isolates of fungi against two-spotted spider mite. To show the multiple roles of entomopathogenic fungi against plant pathogen, the antimicrobial activity of selected 12 isolates were evaluated to plant pathogenic bacterium Ralstonia solanacearum and fungus Botrytis cinerea. Various antimicrobial activities were observed against these plant pathogens. Consequently, these entomopathogenic fungi would be offered an alternative for dual control agents against the two-spotted spider mite and plant diseases.

Entomopathogenic fungi have been widely studied for their potential as the effective biological control agents. They produce variety of secondary metabolites with insecticidal activities, and it is reasonable to assume that entomopathogenic fungi might produce secondary metabolites modulating juvenile hormone for their survival against defense mechanisms of host insect. In this study, Beauveria spp. and Lecanicillium spp. strains cultured on unpolished rice medium were extracted with acetone. Both extracts showed juvenile hormone antagonist (JHAN) activities in the yeast-two hybrid β-galactosidase assay. In addition, they showed high insecticidal activities against Aedes albopictus, Plutella xylostella, and Ostrinia furnacalis. These results suggested that secondary metabolites of entomopathogenic fungi could be useful for development of novel IGR insecticides.

Alternative control agents, hopefully overcoming the present issues and problems in agrochemicals, should be considered and finally applied to the vector controls. Entomopathogenic fungi can used as one of the possible novel control agents and great considerations are given to the control of soil- or water-dwelling stages of vectors, such as mosquitoes and ticks. In our research group, the entomopathogenic fungal library has been constructed using the mealworm-based isolation system, which showed a variety of opportunities of their use in vector control. Important key production technologies including granular formulation have been developed to increase their industrialization. Some entomopathogenic fungal isolates showed high biological performance in the control of mosquitoes and ticks in field stands. R&D of down-stream process should be seriously considered as the key step.

Various arthropods have directly and indirectly threatened human life by transmitting human pathogens such as malaria and Zika virus as well as by damaging crops such as direct feeding and transmission of plant pathogens. According to WHO, vector-borne diseases account for over 17% of all infectious diseases and there are over 1 million deaths from the diseases such as malaria, dengue, etc., globally. About 13% of total crop production is destroyed by agricultural pests during crop production and storage. To control medical or agricultural pests chemical pesticides have been used, but recently because of concerns about environmental pollution and human health the demands for eco-friendly control method are increasing. Insect pathogens are good alternative candidates instead of chemicals. Over 50 entomopathogens including viruses, bacteria, fungi and nematodes are now commercially used as microbial pesticides. Entomopathogenic fungi have also been evaluated as control agents for a diverse insect pests such as aphid, moth, thrip, whitefly, mosquitoes, tick, etc. We will discuss a development of microbial pesticides using, especially, entomopathogenic fungi to control noxious arthropods to agricultural crops and human.

Microbe have been considered as potential control agents for pest, as alternative to chemical control methods. Among entomopathogens, fungi cause the mortality by penetrating the cuticle of pest and/or by metabolites such as toxin. Not only this direct control effect of fungi, but repellency of fungi also may be used to prevent the pest. Repellence effect of fungi is considered as inhibitory factor to control termite. A study was reported in Japan that termite was able to detect and remove the conidia of fungi on their surface. The termite can escape from fungal infection and protect their colony. There is few study that insect pest such as moth can detect and avoid the virulence fungi. Therefore, we has been conducting the detection and avoidance of beet armyworm to high pathogenic fungi, Paecilomyces fumosoroseus. Adult of the beet armyworm avoided oviposition at Chinese cabbage treated with P. fumosoroseus compare to control. This result may be used to prevent the infestation of moth in crop production.

The pursuit of fungal biocontrol agents is a complex process but there can be no doubt that the process of finding an optimal isolate for a particular target needs to draw on a large-scale program to assess many candidate cultures. The supply of such cultures is facilitated by the existence of so enormous, comprehensive and accessible source of germplasm as exists in the USDA-ARS Collection of Entomopathogenic Fungal Cultures (ARSEF). This collection includes more than 13,000 isolates of more than 710 fungal taxa from 1,300 hosts and substrates from 2,440 locations. The global dependence on very few entomopathogenic fungal species–most notably, species of Beauveria and Metarhizium–is understandable within regulatory and commercial constraints, but might actually represent an undesirable and unhealthy degree of stability in the realm of fungal biocontrol of insect pests. deserves to be reconsidered by broadening the spectrum of highly specific pathogens and the means by which they might be applied. Unfortunately, a recent change in the rules of nomenclature applicable to such pleomorphic fungi as Beauveria, Metarhizium, Isaria, and the numerous other entomopathogens of the ascomycete order Hypocreales have not contributed to stability or certainty in how–and, indeed, which–names of fungal genera are to be applied. Some of the effects of the changes that became effective on 1 January 2012 will be discussed. Many familiar names of entomopathogenic fungi are necessarily changing under these new rules, but the choices of which names much be used and which must be discontinued may not be definitively stabilized until 2023 (at the next International Botanical Congress after the 2017 Congress in Shenzhen, China).

The population of managed honey bees has been dramatically declining the recent past in worldwide. The one of most common disease of bees is nosemosis, the nosemosis is caused by microsporidia in the genus Nosema. Nosema apis and N. ceranae have been described as honeybee pathogens. These microsporidia are highly evoloved fungi with an obligately intracellular parasitic lifstyle. The disease causes significant detriment to honey production and results in economic losses. In our knowledge, Fumagillin is the only antibiotic approved for control of nosemosis in honey bees, however this antibiotic may have unintended effects on the honey bee host, ultimately contributing to increased prevalence and pathogenicity of Nosema. Therefore, we screened anti-Nosema substances from entomopathogenic fungal culture filtrates using in vitro polar tube germination assay. These fungal metabolites are employed as antibiotic agents. As results, Total 3 samples (23% of 13 total samples) showing the germinating inhibition against N. ceranae. This screening method may be useful for the detection of anti-Nosema substances from various samples and selected samples in this study may be a good feature to be used in the development of a new biocontrol method of nosemosis.

The present issue of insect resistance and environmental toxicity of pesticides is triggering deep discussion about the pest management tactics, in which pest monitoring and control activity are mainly involved. Novel control agents, hopefully overcoming the present issues and problems, should be researched and commercially applied to the farm fields. With the monitoring-based research, additionally we have to focus on the control-based, particularly control agent-based research and application. Entomo- pathogenic fungi can used as one of the possible novel control agents once considerations are given to the control of soil- or water-dwelling pests. In our research group, the entomopathogenic fungal library has been constructed using the mealworm-based isolation system, which showed a variety of opportunities of their use in pest control. Important key production technologies including granular formulation have been developed to increase their industrialization. Some entomopathogenic fungal isolates showed high biological performance in the control of rice weevils, western flower thrips and Japanese bettles in field stands. To elucidate the fungal mode of action, a fungal transformation system using AtMT and gene identification tools were established. Recently a more deep study about the relationship between insect and entomopathogenic fungi is be investigated using RNA seq. We suggest that to make the entomopathogenic fungal products be applied to agricultural farm field, R&D of down-stream process should be seriously considered as the key step.

ocust, Locusta migratoria (Orthoptera: Acrididae) is one of the outbreaking pests worldwide and such big occurrence was recorded in 2014, Korea, however little consideration was given to the management strategy of the pest. Herein we established a indoor locust-rearing system and constructed a locust-pathogenic fungal library to further facilitate the resources to be used as possible biological control agents. A locust colony was provided from the National Institute of Agricultural Science and Technology and reared in corn or barley plants at artificially manipulated rooms. The critical developmental stages, such as oviposition, hatching and mating were successfully proceeded. Entomopathogenic fungal granules were treated to the locust (2 g/rearing box), and in 5~7 days mycosis was observed in the membranous cuticles of head, abdomen and legs. In particular JEF-003 (Metarhizium anisopliae), JEF-186 (M. lepidiotae) and JEF-187 (Clonostachys rogersoniana) showed high virulence against the locust. A population of locust was exposed to the entomopathogenic fungal conidia-incorporated soil to investigate the possibility of the fungal isolation from natural soil, which resulted in the pathogenesis in 7~10 days in laboratory conditions. More than 80% of control efficacy was observed in the greenhouse trial of fungal granular application. This work suggests that locust rearing system was successfully established and entomopathogenic fungi can be used to control the migratory locust.

Entomopathogenic fungi are facultative microorganisms, dwelling in soil or infecting host insects, and some of the genera have been used as biological control agents worldwide. Collection of fungal isolates should be a platform for the development of highly effective resources, thus in this work we constructed a fungal library using a mealworm pathogenecity-based fungal collection method and further characterized some isolates with high virulence. A phylogenetic three was generated, and of the isolates 17 isolates’ biological features were characterized, such as morphology, spectrum of virulence, cultural characteristics, thermo-stability of fungi, production of biologically active materials, such as enzymes. This work reports an attractive entomopathogenic fungal library including the information of effective isolates in pest management.

Insects constitute the largest and most diverse group of animals on Earth. They also serve as the hosts or nutrient sources for an immense assemblage of parasites, pathogens, and predators, ranging from bacteria and fungi to plant and animals. More than 700 known fungal species from 100 genera have adopted an entomopathogenic lifestyle. These fungi are widely distributed, occurring in aquatic, forest, and agricultural habitats, and are often used as active ingredients in microbial insect pest control agents. Their mode of action against insects involves the attachment of conidia to the insect cuticle, followed by germination, cuticle penetration, and internal dissemination throughout the insect. During this process, secreted enzymes, protein toxins, and secondary metabolites can be used by the fungus to overcome the host immune system, modify host behavior, and defend host resources against competing pathogens and saprophytes. In some cases, the host insect relationship has been found to be associated with bioactive fungal metabolites. These metabolites exhibit a wide variety of insecticidal, antibacterial, antifungal, anticancer, antioxidant, and antiviral activities. Using molecular techniques and phylogenetic analyses, both the asexual (anamorphic) stages and sexual (teleomorphic) stages of entomopathogenic fungi have recently been shown as linked together. Therefore, entomopathogenic fungi, especially in complex with the host insect, might be a promising source of bioactive molecules of pharmaceutical and various industrial interests. Here, we evaluated the antimicrobial activity of entomopathogenic fungi metabolites against plant pathogenic bacteria and fungi for the use in agriculture. The radicals scavenging activity and the anticancer activity were also evaluated for pharmaceutical interests.

Various insect pests infest crops including vegetables and ornamentals during crop production. Chemical pesticides have generally used until recently to control pests. Many pests are very difficult to control using organic pesticides because of the development of insecticide resistance and their rapid population increase. Entomopathogens are the promising alternative control methods. Entomopathogenic fungi are good candidates to control sucking insects such as aphid, whitefly and mite because the fungi can infect without ingestion. Conidia or blastospores of fungal entomopathogens are sprayed onto target plant and/or insect, adhered on insect surfaces, and penetrated into hemocoel through insect cuticle. Then the fungus utilize insect nutrients and kill the host insect. During this process, fungus was influenced by environmental conditions such as temperature, relative humidity and UV light. These are causing slow mortality and preventing wider application and use of mycopescitide using entomopathogenic fungi. In addition, control efficacy with fungal entomopathogen differed fungal isolate and host insect. Therefore, we need to study selection of high virulence isolate, mass production, formulation and application techniques to develop mycopesticide.

Entomopathogenic fungi are natural enemies of insects and contribute to the regulation of their host populations. Numerous fungal species have been isolated from their respective hosts or environmental conditions such as soil and used as pest control agents for a long time in many countries. Recently, the isolation and characterization of native entomopathogenic fungi are essential for gaining insight into the naturally occurring fungal biodiversity of a specific region and to providing a pool of potential biological control agents for pest control purposes. Moreover, exotic strains of entomopathogenic fungi that have been developed for use as pest control agents in a different country could be ineffective due to strain and environmental differences. Therefore, investigating the occurrence and distribution of native entomopathogenic fungi is critical for their use as pest control agents in a given location. Here, we report the isolation, distribution and characterization of entomopathogenic fungi from soils in Korea to establish a pool. During infection against insects, entomopathogenic fungi produce various enzymes, protein toxins and secondary metabolites to overcome host defenses and ultimately kill the host, and to defend host resources against competing pathogens and saprophytes. These metabolites exhibit a wide variety of insecticidal, antimicrobial, anticancer, antioxidant, and antiviral activities, and they have been suggested as potential candidates for the development of new bioactive agents. Entomopathogenic fungi isolated from Korean soils were also evaluated for these additional roles besides pathogenicity.

자연 감염된 담배가루이로부터 곤충병원성진균을 분리 동정하고, 이 균주에 대하여 배양특성, 자연발병 요인, 그리고 주요 온실해충인 담배가루이, 점박이응애, 대만총채벌레에 대한 살충력을 검정하였다. 분리 균주의 형태적 특성은 직립한 분생자병에 윤생으로 호리병 형태의 4-6개phialide를 지녔고, 분생포자의 크기는 3.0-3.4 ㎛ 이었다. 분리 균주의 rDNA의 ITS영역 염기서열 분석에서 Isaria fumosorosea (AF461747)와 는 99%의 높은 염기서열 유사도를 보였다. Potato dextrose agar, Sabouraud maltose agar+yeast extract 그리고 Sabouraud dextrose agar+yeast extract 배지에서 IFs 균주는 24℃의 SDAY 배양에서 균사 성장이 가장 양호하였으며, 15℃보다는 35℃의 고온에서 균사 성장이 좋았다. I. fumosorosea IFs-08, -09 균주는 담배가루이에 대하여 각각 96.7, 93.9%의 높은 살충율을 보였으며, 점박이응애(92.0, 84.9%) 그리고대만총채벌레(84.4, 81.5%)에서도 80-90%정도의 살충율을 보인 반면 KACC로부터 분양받은 Isaria tenuipes, Isaria farinosa, Isaria fumosorosea 균주들은 10-20% 내외의 낮은 살충율을 나타내었다.

Entomopathogenic fungi formulated as wettable powders and suspension concentrates have been sprayed to crop pests for pest management. However, the use of fungal granules to control paddy field pests has not been fully explored. Herein, several Beauveria bassiana isolates (ERL 1170, 1578 and 836) were produced as granules using a millet-based solid culture. The granules were applied to the rice nursery 3 days before transplanting and their control efficacy against rice water weevils was determined in paddy fields. The solid cultures produced ~1×108conidiag-1ofmilletgrains10daysaftertheinoculation. The granules were applied to the soil in the rice nursery 3 days before the rice seedlings were transplanted in the paddy fields. Rice in plots with granules of ERL1578 had 17.3% leaf damage (74% control efficacy) 14 days post application, whereas rice plants in the non-treated control had 66.5% damage. Rice plants treated in the nursery with ERL1170 and ERL836 had 52~54% damage. In the rice plots previously treated with ERL1578 the smallest numbers of larvae and adults were observed 38 days post application. In laboratory conditions, ERL1578-treated larvae were tuned pink and covered with mycelial mass. Applications of millet-based B. bassiana granules on rice nursery soil can be an effective and efficient biological control strategy for the management of rice water weevils. This method is relatively inexpensive and requires less labor compared to practices involving the spraying of fungi directly on rice in paddy fields.

Mealworms, Tenebrio molitor (L.) is used as an important animal feed additive for growth promotion and health management, but potentially exposes to fungal infection. In this work, virulence of two species of entomopathogenic fungi against the insect, and the relationship between abiotic features and virulence were investigated. Secondly our consideration was also given to the effect of chemical fungicides on conidial germination for risk control. Between Beauveria bassiana (Bb) and Metarhizium roberstii (Mr) (previously M. anisopliae), Bb isolates had much higher virulence (~100% mortality in 3~4 days after the treatment), rather than Mr isolates in laboratory assays. Next, fungus-treated mealworms were kept at wheat bran at 20, 25, 30 and 35℃ with 3, 6, 9 times of water spray to the feeds for set-up of different humidity conditions. Inoculation of fungi to mealworms was conducted by fungal spray and feeding methods, which resulted in higher virulence in feeding method. In the feeding method, all temperature treatments except 35℃ showed high virulence against mealworms, but any significant relationship between virulence and humidity was not observed. In the chemical fungicide screening, fluazinam (CAS No. 79622-59-6) and mancozeb (8018-01-7) significantly inhibited the germination of Bb and Mr conidia. This work suggest that contamination of wheat bran with fungal pathogens, particularly B. bassiana may induce mycosis of mealworms, but introduction of effective fungicides possibly reduce fungal infection.