Pollutants can exist in the soil for a long time and alter the bacterial community. Using lubricants to prevent the wear of chainsaw blades is necessary for thinning activities and wood harvesting. We investigated the influences of soil contamination with chainsaw lubricants on soil bacterial communities. Bio-oil, mineral oil, and recycled oil were scattered on each treatment to investigate variations in soil bacterial structure during treated periods using the Illumina MiSeq sequencing platform. The results obtained were 5943 ASVs, 5112 ASVs, and 6136 ASVs after treatment at one month, six months, and twelve months, respectively. There was a significant difference in Shannon and Simpson indices between treatments and controls. A total of 46 bacterial genera with an average relative abundance of more than 1.0% were detected in all soil samples. Massilia was the most common genus detected in control at one month, with an average relative abundance of 14.99%, while Chthoniobacter was the most abundant genus detected in bio-oil, mineral oil, and recycled oil treatments at one month, with an average relative abundance of 13.39%, 14.32%, and 10.47%, respectively. Among the three chainsaw lubricants, bio-oil and mineral oil had fewer impacts than recycled oil. The abundances of several functional bacteria groups in the bio-oil treatment were higher than in other treatments and controls. Our results indicated that different chainsaw lubricants and their time of application affected the soil bacterial community composition.

A key role that fungal endophytes play in interacting with their host plant can be defined by the fact that they promote the growth of plants and enhance the tolerance of the host against plant pathogens using bioactive compounds that they produce. Several studies utilizing endophytic fungi as a source of biological control against plant pathogens were conducted, and a representative example includes Aureobasidium protae from common wheat (Triticum aestivum), which inhibited the mycelial growth of Fusarium graminearum and Fusarium culmorum, causal agents of Fusarium head blight disease. Our previous study indicated that three endophytic fungal isolates, E089 (Daldinia childiae), E282 (Nectria balsamea), and E409 (Colletotrichum acutatum), showed antifungal activities against D. quercus-mongolicae, an ascomycetous fungus that is reported to be associated with oak mortality in South Korea. The objectives of this study were to optimize and evaluate antifungal efficiency for these endophytic fungi against D. quercus-mongolicae, and this was achieved using culture filtrate retrieved from the three above-mentioned endophytes and fractions isolated from the culture filtrate. Of those, the culture filtrate from E282 showed higher mycelial growth and sporulation inhibitions on PDA medium where D. quercus-mongolicae was grown. In addition, three fractions, including hexane, CHCl₃, Et₂O, and H₂O, were tested for antifungal activities against D. quercus-mongolicae. The results revealed that the Et₂O fraction showed higher mycelial growth and sporulation inhibition rates. Taking these results together, the endophytic fungus, N. balsamea, which exhibited high antifungal efficiency, can be effectively used as a biocontrol agent for the management of oak wilt disease in the country.

Endophytic fungi play a vital role in protecting and promoting the growth of their host plants. The diversity of fungal endophytes has been documented across different host plant species and varies depending on factors such as the species of the host, ecological conditions, and the health status of the plant. We isolated endophytic fungi from Prunus yedoensis trees with different decay rates. A total of 31 species were isolated from decayed trees, while 33 species were obtained from healthy trees. The number of endophytic fungi exhibiting antifungal activities against wood decay fungi was higher in healthy trees, with 10 species showing activity compared to only 1 species from decayed trees. Endophytic fungus Fusarium acuminatum (BEN48) had the highest inhibition rates against Trametes versicolor, Ganoderma gibbosum, and Vanderbylia fraxinea. Heating conditions did not significantly affect the inhibitory ability of the culture filtrate from BEN48 on wood decay fungi. At 50% concentration, the inhibitory abilities of the culture filtrates against Trametes versicolor, Ganoderma gibbosum, and Vanderbylia fraxinea were 96.5%, 64.1%, and 92.7%, respectively. The inhibitory effects against Trametes versicolor decreased at concentrations of 30% and 10%, resulting in inhibition rates of 83.7% and 50.8%, respectively. For Ganoderma gibbosum, the inhibition rate reduced to 52.6% at 30% concentration and 24.5% at 10% concentration. For Vanderbylia fraxinea, there was no significant difference between the 30% and 10% concentrations, and the inhibition rates for both concentrations were high, measuring 89.9% and 88.8%, respectively. Hence, Fusarium acuminatum (BEN48) has promise as a biocontrol agent for managing wood decay fungi.

The diet of wild boars (Sus scrofa) is highly diverse, consisting of both plant and animal materials, and their foraging behavior varies seasonally. However, limited research has investigated the composition of macrofungi in the diet of these omnivorous mammals, and relevant information remains scarce. This study aimed to assess the diversity of plant, animal, and macrofungal components in the diet of wild boars and to evaluate seasonal variations in Bukhansan National Park, Republic of Korea. Fecal samples were collected across different seasons, and DNA metabarcoding was applied to compare the taxonomic composition of dietary items. The results revealed that the wild boar diet included 54 plant genera, 9 animal genera, and 22 macrofungal genera. Among the plants, Pueraria, Quercus, and Ipomoea were the most dominant, with relative abundances of 21.3%, 18.3%, and 16.4%, respectively. The primary animal taxa consisted of Neomyia (54.7%) and Didea (39.4%), while Rhizopogon accounted for 95.3% of the macrofungal sequences detected. Overall, the study demonstrated clear seasonal variation in the diet of wild boars, reflecting their remarkable adaptability to changing environmental conditions.

Oak trees are widely distributed nationwide and account for approximately 24% of the total forest area in South Korea. However, these species are currently threatened by oak wilt disease caused by Dryadomyces quercus-mongolicae, leading to significant economic and ecological losses in the forestry industry. This study evaluated the effectiveness of culture suspension and lyophilized powder formulations of Streptomyces blastmyceticus in controlling oak wilt disease on Mongolian oak (Quercus mongolica). Field experiments were conducted using trunk and root injection methods in Q. mongolica plantations. The non-conductive area (NCA) of sapwood and colonization rate of the oak wilt fungus were analyzed and compared across treatments. In the Chuncheon experiment, Kangwon province, only the root injection of fungicide showed a significant difference compared to the culture suspension treatments. There were no significant differences between culture suspension and lyophilized powder treatments in Uiwang, Gyeonggi Province. Specifically, both preventive and curative treatments using culture suspension and lyophilized powder of S. blastmyceticus resulted in significantly different NCA values compared to the negative control (8.7%) and positive control (88.5%). The NCA for culture suspension ranged from 33.3% to 49.9%, and for lyophilized powder, from 37.3% to 43.9%. The colonization rate of the oak wilt fungus was lowest (9.72%) in the preventive treatment using lyophilized powder via trunk injection. For the culture suspension, the lowest colonization rate (20.83%) was observed in the curative treatment using trunk injection. These findings suggest that the lyophilized powder formulation of S. blastmyceticus efficiently suppresses the progression of oak wilt disease under field conditions.