Metarhizium은 대표적인 곤충병원성 진균 중 하나로, 종에 따라 매우 다양한 곤충에게 병원성을 일으키는 폭 넓은 기주범위를 형성한다. 이들이 주로 생성하는 것으로 알려진 destruxins (DTXs)이라는 2차 대사산물은 살충 활성 뿐만 아니라 항바이러스, 항증식, 항암 등 다양한 분야에서 효능이 연구되고 있어, 해당 물질에 대한 관심이 집중되고 있다. 살충 물질로서의 DTXs는 여러 곤충에 있어 병원성을 나타내는 것이 확인되었으나, 해충 으로서 전 세계적으로 심각한 경제적 피해를 일으킴과 동시에, 화학 살충제 저항성 문제가 야기되고 있는 목화진 딧물에 대해서는 아직 DTXs의 역할이 연구되지 않고 있는 실정이다. 본 연구에서는 목화진딧물에 대해 곤충병원 성 진균 Metarhizium spp.의 병원성 발현에 DTXs가 미치는 역할을 간접적으로 확인하기 위해, qPCR을 활용하여 진균 처리 후 목화진딧물 사망 시간과 관련하여 충체 내 DTX 합성효소의 발현을 비교 분석하였다.

Mycoviruses are a group of viruses that infect filamentous fungi. While most hosts infected with mycoviruses do not show any symptoms. In some cases, mycoviruses induce various phenotypic changes include alterations in morphology, drug resistance, pathogenicity, virulence, sporulation, and growth. Entomopathogenic fungi are one of the integrated pest management agents as an alternative to conventional insecticides. Mycoviruses have the potential as supportive agents, enhancing the efficiency of the insecticidal activity of the fungi. Studies about mycoviruses themselves and their interaction with their hosts, especially entomopathogenic fungi, are needed to realize their full potential. In this work, the sequence of the dsRNA element isolated from the entomopathogenic fungus Metarhizium pinghaense 4-2 strain was determined. Through this study, we report the sequence of a dsRNA virus isolated from the Metarhizium pinghaense for the first time. In further studies, the ORF of the mycovirus that induces a phenotype change in the host will be researched.

Entomopathogenic fungi have been studied to control insect pests as an alternative to chemical insecticides. However, all fungi haven't a high virulence against pests. In this study, we compared the biological characteristics of Metarhizium anisopliae strains. First, we selected four M. anisopliae strains and compared the thermotolerance, conidial productivity, and virulence. For the thermotolerance test, conidial suspensions were exposed to 0, 30, 60, and 90 min at 45 °C. As a result, the conidial germination rates were over 95% when exposed for 0 min but, were 64, 37.7, 6, and 3% when exposed for 30 min at 45°C, respectively. To compare conidial productivity, 200g of millet were used and inoculated with a conidial suspension of 1 ml (1×107 conidia/ml). Conidial productivity was investigated after 14 days. As a result of conducting a virulence test against mealworms using a spray method, differences in virulence between strains were confirmed.

Aphids are well-known insect pests that, due to their feeding habits, affect various crops' productivity and marketability. Additionally, they cause significant damage worldwide as vectors of viruses. Chemical pesticides are widely used to control these agricultural pests. However, due to resistance to various chemical pesticides, pest control is becoming difficult in agricultural environments. Entomopathogenic fungi such as the genus Metarhizium and Beauveria are being extensively researched as alternatives to these chemical pesticides. In this study, the mycological properties of isolated from soil Metarhizium pemphigi IPBL-H and the insecticidal activity of this strain against Myzus persicae and Aphis gossypii were evaluated for potential of development as a biopesticide.

In this study, Bacillus velesensis TJS119, isolated from freshwater, demonstrated growth inhibition against insect pathogenic fungi. The culture medium of the B. velezensis TJS119 strain underwent sequential fractionation with n-hexane, chloroform, ethyl acetate, n-butanol, and water. Notably, the n-butanol fraction exhibited significant antifungal activity against Metarhizium anisopliae and Beauveria bassiana. LC/MS analysis of antifungal peaks identified the production of various lipopeptides by B. velezensis TJS119, including two types of iturin A (C14, C15), four types of fengycin A (C14, C15, C16, C17), and two types of fengycin B (C16, C17). The antifungal efficacy of Iturin A and Fengycin against insect pathogenic fungi was further validated using the paper disc diffusion method. These findings underscore the potential of B. velezensis TJS119 as a promising candidate for future research and applications in the realm of agricultural biological controls against fungal diseases.

Cryptotympana atrata belongs to the family Cicadidae, has long been recognized as a damaging plant-sucking pest, and is distributed in East Asian countries. In addition, their cries cause direct harm to us through noise pollution and also reported twig damage in the forest environments. In this study, we isolated strains of the entomopathogenic fungus Metarhizium that occurred from C. atrata collected this year. Here, we provide the morphological character and molecular phylogenetic relationship of this species. This is the first record of the entomopathogenic fungus Metarhizium viridulum isolated from C. atrata in Korea and provides a candidate strain with potential use for biological agents.

An outbreak of stick insects, Ramulus mikado, as forest pests in South Korea has become a topic of concern. While other countries have reported these insects being severely affected by the entomopathogenic fungus Metarhizium spp., comprehensive research in South Korea remains limited on this topic. In our two-year investigation, we investigated the infection rate and mortality of R. mikado caused by Metarhizium anisopliae. In 2022, specimens were collected from Cheonggyesan, and in 2023 from Geumamsan. Although no infections were confirmed in the specimens collected in June of both years. Beginning in July, mortality and infection rates were greatly increased. In conclusion, the summer monsoon appears to create hot and humid conditions in the forest, contributing to reduced survival rates for these insects due to infection by M. anisopliae.

흰점박이꽃무지 (Protaetia brevitarsis) 유충은 동아시아에서 식용 및 약용으로 널리 사용되고 있다. 흰점박이꽃무지 수요 증가로 인해 유충의 대량 사육 방법이 필요하지만 좁은 공간에서 대량으로 유충을 사육할 경우 곤충 병원성 질병 감염에 취약해진다. Metarhizium anisopliae는 흰점박이꽃무지 유충에 치명적인 곤충 병원성 곰팡이 중 하나이다. 이를 저해하기 위해 항진균 성분이 함유된 옻나무 (Rhus verniciflua Stokes) 추출액을 첨가하였고, 연구 결과 1% 옻나무 추출액을 첨가한 경우 녹강균에 의한 유충의 치사율이 유의미하게 낮았다. 또한 일반톱밥을 급여한 대조구에 비해 옻나무 추출액 처리구에서 유충의 무게가 더 무거웠고 유충 기간이 짧아 지는 것을 확인하였다. 따라서 이 연구를 통해 곤충 병원성 곰팡이에 대한 옻나무 추출액의 항진균 효과를 확인할 수 있었으며 흰점박이꽃무지 유충 사육 시 옻나무 추출액을 첨가 하여 급여한다면 병원성 곰팡이에 의한 유충의 치사율을 낮추고 증체량을 높이는 데 효과가 있을 것이다.

Metarhizium anisopliae (녹강균)는 흰점박이꽃무지에게 질병을 일으키는 곤충 병원성 곰팡이 중 하나이다. 이러한 곰팡이의 병원성은 환경 조건에 의해 영향을 받는다. 녹강균에 대한 흰점박이꽃무지 유충의 민감성을 알기 위해 온도(20℃, 25℃, 30℃), 상대습도 (RH 40%, 50%, 60%, 70%), 톱밥 수분함량 (40%, 50%, 60%)이 다른 사육 조건에서 유충의 치사율을 확인하였다. 녹강균을 처리한 흰점박이꽃무지 유충의 치사율은 온도에 따라 차이가 나타나지 않았으나, 낮은 상대습도 (RH 40%)와 톱밥 수분함량 (40%)에서 유충의 치사율이 높았다. 녹강균에 대한 1령, 2령, 3령 유충의 치사율은 1령에서 가장 높게 나타났다.