Japanese pine sawyer beetle, Monochamus alternatus Hope (Coleoptera: Cerambycidae) is considered as a serious pest in pine trees. To develop an eco-friendly strategy to manage this forest insect, we collected entomopathogenic fungi from Korean soil and assessed their virulence against the adults of the insect in laboratory conditions. As a result, two isolates with conidial suspension (1.0×107conidia/ml), showed 87% and 90% mortality 12 days after fungal treatment, respectively. We assessed the potential of the fungi-derived destruxin and protease as additives to the fungal isolates, and they showed insecticidal activity via feeding and spraying treatments. Finally, we produced fungal conidia in massive solid cultures and formulated wettable powders, and now studying optimal conditions of oil-based formulation with two isolates. Based on these results, we are evaluating the control efficacy of the fungal agents against M. alternatus in field conditions.

Most of the expressway concrete pavements in Korea have been constructed with jointed plain concrete pavements. However, the premature failure of joints occurred on some routes and it is considered to be related to the durability of concrete. Korea Expressway Corporation has been continuously devoting efforts to increase the durability of concrete, and recent research has shown that premature failure of jointed plain concrete pavement constructed recently has decreased. The durability of pavement concrete is determined by internal and external factors. Currently, the durability of pavements concrete is controlled by controlling the quantity and the spacing factor of internal air. In this study, the feasibility of evaluating concrete durability through absorption performance tests was examined. The absorption performance was evaluated by applying ASTM C 1585 and modified NBN B 15-215 in Belgium and applied to the pavement concrete mixed in the laboratory or collected on site. Each test is a method to evaluate water absorption performance, but ASTM evaluates the absorption performance through the upper surface and NBN evaluates the absorption performance through the entire surface of specimens. In this study, the absorption performance of the pavement concrete measured according to the test method was compared and the advantages and disadvantages of the performance evaluation method were examined through comparison of test results and procedures. As a result of the absorption performance test on the cores collected at the site, the amount of water absorption in the region where the few premature failure was occurred was relatively small. Also, the specimen of lower water cement ratio absorbed the smaller amount of water. And the small amount of aggregate at the surface showed tendency of the large absorption of the water. The amount of absorption due to the increment of air content showed a moderate increment but it was relatively small. This study has confirmed the possibility of estimating the durability through the evaluation of the absorption performance of concrete. However, further study is needed to extend the results obtained from the test method to the evaluation criteria of pavement concrete.

Roller Compacted Concrete Pavement (RCCP) is placed by roller compaction of a mixture of less cement and unit water content and more aggregates and provides excellent early strength development with the help of interlocking of aggregates and hydration. The unit cement content of RCC pavements accounts for 85% of conventional pavements, with low drying shrinkage. As low drying shrinkage leads to smaller crack widths than ordinary concrete, RCC pavements can help elevate reflecting crack resistance if applied to a base layer of a composite pavement system. In a composite pavement with an asphalt surface laid over a concrete base, pavement temperature change is important in predicting pavement performance. As movement of the lower concrete layer is determined by temperature depending on pavement depth, temperature data of the pavement structure serves as an important parameter to prevent and control reflecting crack. Among the causes of reflecting crack, horizontal behavior of the lower concrete layer and curling-caused vertical behavior of joints/cracks are considered closely related to temperature change characteristics of the lower concrete course (Baek, 2010). Previous studies at home and abroad about reflecting crack have focused on pavement behavior depending on daily and yearly in-service temperature changes of a composite pavement (Manuel, 2005). Until now, however, studies have not been conducted on initial temperature characteristics of concrete in composite pavements where asphalt surface is placed over an RCC base. Annual temperature changes of in-service concrete pavements go up to 60 ℃, and those of asphalt overlays become around the twice at 110 ℃. This study evaluated initial crack behavior of composite pavement by investigating pavement temperature by depth of an RCC base and analyzing joint movement depending on change to temperatures of continuously jointed pavements. Findings from the study suggest that in composite pavements and asphalt overlays, time of laying asphalt has an important impact on crack behavior and reflecting crack.

Roller Compacted Concrete Pavement (RCCP) is a pavement placed and compacted using an asphalt paver and a compaction roller by applying a small amount of concrete mixture and shows excellent structural performance as a result of hydration reaction of cement and interlocking of aggregates by roller compaction. It also provides economic advantages over conventional concrete pavements by reducing unit cement content and construction period, simplifying construction process, and decreasing traffic closure time (Wayne, 2006). However, given that it tends to show lower IRI levels than common concrete pavements since its low unit water content and binder weight ratios make uniform quality control difficult and roller compaction after paving makes the surface irregular and rough, with rough profile at the bottom of the pavement being reflected on the surface, RCCP is used mainly in port and industrial roads for low speed (60km/h or less) traffic (Dale Harringtion, 2010; Gregory, 2009). In order to apply RCCP to high-speed roadways, diamond grinding (DG) or asphalt overlay that is highly effective in improving roughness is needed (Fares Abdo, 2014; Gregory, 2009). Applying DG over RCCP leads to excellent skid resistance and noise reduction effects as a great percentage of aggregates makes the pavement surface rough, enhancing durability of concrete and the life of DG functionality. In addition, RCCP can be used as a high performance base layer of composite pavements, as it can reduce reflecting cracking at joints and cracked sections thanks to early strength development and low drying shrinkage of concrete. In this study, we assessed longitudinal roughness improvement effects by roughness-affecting factor by applying DG methods and asphalt overlays to three RCCP sites with a variety of sub-structural conditions and analyzed the effects on roughness of existing RCC pavements depending on surfacing method (DG, APOverlay).

Beauveria bassiana (Bb) is a potential biopesticide against western flower thrips. To understand molecular characteristics of two Bb isolates (ERL836 and JEF-007), whole genome sequencing and RNA-seq were performed. The whole genome of Bb ERL836 was sequenced (3,934,801,443 bp) using Pacbio sequencing and 15 contigs were analyzed. To understand the molecular mechanisms of pathogenicity in two Bb genome (before infection and after infection), next generation sequencing (NGS) was analyzed to compare transcriptomes. A result of differentially expressed gene (DEG) showed that 2,689 contigs were up-regulated and 2,619 contigs were down-regulated. Randomly selected five genes were validated to be highly up-regulated. This work can provide an understanding of the interaction between Bb and westetn flower thrips.

Japanese pine sawyer, Monochamus alternatus Hope (Coleoptera: Cerambycidae) in forest is considered as a serious forest pest in pine trees. In this study, we collected entomopathogenic fungi from soil and assessed their virulence against the adults of the inset using a spray method in laboratory condition. Two entomopathogeinc fungi isolates showed high virulence against the adults. In the concentration of 1.0 × 107conidia/ml, the mortality rate of the adults were 53% and 60%. In semi-field condition, one isolate showed a virulence of 60% against the adult. Consequently, we confirmed the possibility of the fungal isolates in controlling the beetles. In near the future, we will investigate several factors which is possibly related to the control of the forest insect pest using entomopathogenic fungi in field conditions, given the importance of fungal formulation and practical application methods.

The hard tick, Haemaphysalis longicornis (Ixodida: Ixodidae) is one of the vectors of severe fever with thrombocytopenia syndrome virus (SFTSV) causing in humans, however little consideration was given to the biological control of the pest. Therefore, this study provides a screening method to select entomopathogenic fungi, having high virulence against H. longicornis. The virulence test was conducted by dipping method with a conidial suspension (1×107 conidia/ml). As a result, cadavers of H. longicornis infected with entomopathogenic fungi were obtained by this method. Based on this results, we selected several isolates having high virulence to H. longicornis. We suggest that, selected isolates in this study can be used for the control of H. longicornis.

Entomopathogenic fungi have been known as promising candidates for biological control of insect pests. Recently, researchers consider the fungal thermotolerance in formulations and field applications. In this study, we investigated the production of thermotolerant Isaria javanica and I.fumosorosea conidia through grain-based solid cultures and exposure to light stress. As results, of the ten grain substrates, Italian millet, rice, perilla seed and sesame, rice, sorghum produced highly thermotolerant conidia in the strains. The two strains were exposed to a light stress and a heat stress. And they showed enhanced thermal stability compared to control, when exposed to 45°C for 2 hours. This work suggests that heat-resistant entomopathogenic fungal conidia can be produced by grain-based solid cultures and exposure to light stress.

Melon thrips, Thrips palmi Karny (Thysanoptera: Thripidae) is a serious insect pest of various crops in the world. The management of this pest mainly have relied on chemical agents. However, the overuse of chemical agents for long times causes insect resistance, and negative effects on environment. Therefore, alternative control methods, such as biological control, that are less harmful to the environment and have different mode of action are needed to control this pest. In this study, we isolated entomopathogenic fungi from Korean soil, and characterized them via morphological and molecular identifications and pathogenicity check against Tenebrio molitor larvae. The isolated fungi were subjected to virulence assay against T. Palmi with a conidial suspension of 1×107 conidia/ml in laboratory conditions. This entomopathogenic fungi library would be a good resource to select effective strains for the control of T. palmi in fields.

Entomopathogenic fungi play an important natural role in regulating their insect host populations, and their ecology was also associated with plant and soil. These microorganisms have been living by reacting to insect, plant and environmental factor. The advanced bioinformatics technology such as next-generation sequencing and RNA sequencing has revolutionized in understanding of entomopathogenic fungi. Recently studies provided a lot of information on evolutionary relationships and virulence-related characteristics. We are starting to know where these microorganisms from is, and how they live in nature. The bioinformatics technology will give us further our understanding of the natural roles of these fungi in nature.

The entomopathogneic fungal colonization has become an interesting issue in ecological pest management. Plant-orientedfungi induce plant growth promotion and act as natural control agents against insect pest. Herein this work, we evaluatedthe ability of fungal colonization on bark, branches and leaves of pine tree (Pinus densiflora) to select optimal candidatesfor controlling Japanese pine sawyer (Monochamus alternatus), which is the pine wilt disease vector in Korea. As a result,some Beauveria and Metarhizium isolates could colonize on the substrates of P. densiflora and showed pathogenicity againstM. alternatus. This result suggests that the selected entomopathogenic fungi are possibly candidates for long-term managementof M. alternatus in pine tree forest.

Japanese pine sawyer, Monochamus alternatus HOPE (Coleoptera: Cerambycidae) are considered as important pine forestinsect pests in several countries which transmits the pine wood nematode, Bursaphelenchus xylophylus. In this study, wetried to control Japanese pine sawyer using entomopathogenic fungi to prevent the spread of pine wilt disease in Korea.Several entomopathogenic fungi were exposed to the adults of Japanese pine sawyer and mycosis was observed in themembranous cuticles after 6 days. In particular, two isolates showed high virulence against the adults. The selected 2isolates were sprayed to the adults at 1×105, 1×106 and 1×107 conidia/ml. In the concentration of 1×107 conidia/ml, thesurvival rates of insects were 40% and 47%, respectively. Based on these results, the possibility of controlling the Japanesepine sawyer was confirmed.

Chemical pesticides have been used for persimmon pest control, however the overuse caused insect resistance andenvironmental toxicity. Herein this work, we investigated the biological potential of eco-friendly organic pesticides (biologicals)and entomopathogenic fungi in controlling persimmon pests, Stathmopoda masinisaa and Riptortus pedetris. A botanicalmixture of Chinese scholar tree, goosefoot and subtripinnata extract, Bacillus thuringesis NT0423 and one isolate of Beauveriabassiana showed high insecticidal activity against the pests in laboratory conditions. The selected botanical extract andmicroorganism were combined with a chemical pesticide (buprofezin+dinotefuran WP) and were assessed their controlefficacy in persimmon fields. Compared to the three times of chemical spray, the combination of more than one timeof chemical spray and the selected biologicals controlled the persimmon pests with an acceptable levels. Consequentlyone time of biological spray can be integrated to the spray program where only chemicals are strongly considered.

The hard tick, Haemaphysalis longicornis (Ixodida: Ixodidae) is one of the vectors of severe fever with thrombocytopeniasyndrome virus (SFTSV) causing in humans, however little consideration was given to the biological control of the pest.We evaluated three bioassay methods, such as spray, dipping and dropping. As a result, the dipping method was themost efficient way to measure the fungal virulence. Finally, we constructed a Haemaphysalis longicornis pathogenic fungallibrary to further facilitate the resources to be used as potential biological control agents. A conidial suspension of 1×107conidia/ml was exposed to the ticks by dipping. We confirmed that some isolates were highly virulent to the ticks. Thisresults indicated that some fungi could be used to effectively control the Haemaphysalis longicornis.

Many entomopathogenic fungal isolates received interests for controlling insect pests. But very few numbers of isolatesreached agricultural fields as commercial products. In this study, we investigated the feasibility of grain substrates forconidial production, focusing on conidial productivity and thermotolerance. Next to efficiently use the produced conidiafor spray application, conidia need to be separated from the grain substrates. Isaria javanica and I. fumosorosea conidiawere solid-cultured on ten kinds of cereal grains. Solid-cultured grains were packed in a screen bag and immersed inwater with a variety of surfactants at 100 ppm, such as Silwet, CO-2.5, CO-12, LE-7, PE-61, TDE-3, Tween 20 or Tween80. High levels of conidial release were observed on LE-7, TDE-3 and Tween80 treatments. This work suggests thatthe screen bag can be used to separated conidia from the cultured grains with the help of surfactants.

A genus of entomopathogenic Beaveria bassiana has been widely used in pest management, however little studies havebeen given to its virulence-related genes. To identify the roles of virulence genes, AtMT-induced random mutants weregenerated and followed by localization study with TAIL-PCR. Two genes, Complex I intermediated-associated protein30 (CIP30) and Autophagy protein 22 (Atg22), were predicted as virulence-related genes in B.bassiana JEF-007. To validatethe a possible relationship between two genes and fungal virulence, hpRNAi was performed. A hpRNAi plasmid wasconstructed as a model system to knock down of egfp gene in egfp-expressing B. bassiana transformant. A Real-TimePCR showed the knock down of egfp gene expression via hpRNAi. The CIP30 and Atg22 genes in B. bassiana willbe validated by the established RNAi technique. This work can be a strong platform for the functional genetics in B.bassiana.

Entomopathogenic fungi, widely distributed in nature, have been developed as biopesticides of agricultural pests. However, little is known about isolation method for obtaining a variety of highly virulent strains from the soil. In this work, the previously established method using mealworm (larvae of Tenebrio molitor) as a baiting system was used to efficiently isolate fungal strains from soil, and the isolated fungal library in Korea was established. To isolate entomopathogenic fungi, soil samples from 10 regions of Korea such as Iksan, Imsil, Gunsan, Yeosu, Suncheon, Gwangyang, Jinju, Hamyang, Boseong and Jangseong were collected. Of the collected soils, 21 and 34 isolates of entomopathogenic fungi were isolated from Iksan and Gunsan, respectively. The isolates were classified as genera of Metarhizium, Beauveria and Isaria. This work can suggest an effective insect pathogenic fungal isolation method

Entomopathogenic fungi have been known as promising candidates in biological control. However, a large number of conidia with higher stability should be produced for industrialization. In this work investigated the possibility of several grains for the production of thermotolerant Isaria javanica and I. fumosoroseus conidia. The fungal conidia were produced on ten grains for 14 days in Petri dish conditions. Of the ten granular substrates, millet, perilla seed and barley showed the high conidial production, 15.7 ± 8.4, 17.3 ± 5.2 and 13.5 ± 1.9 × 109 conida/g in I. javanica and 15.9 ± 0.6, 15.0 ± 0.5 and 15.0 ± 0.7 ×109 conida/g in I. fumosoroseus, respectively. However, the two strains showed relatively low thermal stability regardless of substrates, when exposed to 45℃ for 1, 2 and 3 hours. This work suggests a possible substrate for conidial production of entomopathogenic fungi with low cost.

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.

Many turfgrass pests, Ectinohoplia rufipes, Exomala orientalis and Popillia quadriguttata, cause serious damage to grass fields in Korea. In this study, control of turfgrass pests using entomopathogenic fungi were investigated using Protaetia brevitarsis seulensis as an alternative insect. In a preliminary experiment, some Metathizium sp. showed ca. 60% virulence after 7 days exposure to the entomopathogenic fungi. Compared to the contact-exposure, overall a spray treatment showed lower control efficacy against P. brevitarsis seulensis. Furthermore, mortality of various developmental stages of P. brevitarsis seulensis was investigated under laboratory conditions. This work suggests that when treated with fungi mortality of P. brevitarsis seulensis was closely related with developmental stage. These results provide a basic information for the control of P. brevitarsis seulensis using entomopathogenic fungi