A variety of commercial instruments are available for sampling and quantifying microscopic airborne organisms from the environment. Although most samplers are highly sensitive, they are also expensive, costing thousands of dollars per unit, a price that is out of reach for many researchers, especially those looking to design experiments with replication. While looking at options to monitor pine stands for the presence of Fusarium circinatum, the causal agent of pitch canker disease, on multiple sites with several units per site, we developed a simple, low-cost spore trap that allows surveying spore abundance in outdoor environments. The trap consists of a rotating motor that holds a metal rod and two petroleum jelly-coated microscope slides. As the motor rotates, the slides collect airborne particles. To test whether the traps allowed detection of F. circinatum spores, we placed six traps on three sites: an actively-managed slash pine commercial stand located in Lake Butler, FL, a semi-managed loblolly and slash pine stand near Gainesville, FL, and a site with little perturbance at Goethe State Forest, FL, consisting of mainly slash pine trees. The slides were replaced weekly, and F. circinatum was detected by quantitative PCR using species-specific primers. Results show detection of low levels ( $\overline{\mathrm{X}}$ = 1.7–77.1 picograms ± SE = 0.3–39.7) of the pathogen spores with high reproducibility. These traps offer a low-cost solution to spore, pollen, or small insect trapping experiments for initial or general assessment of a pathogen or species population. Their low cost has the added benefit that multiple traps can be deployed per experiment, thus increasing statistical power by using multiple replications.

Fungal endophytes have been recorded in various plant species with a richness of diversity, and their presence plays an essential role in host plant protection against biotic and abiotic stresses. This study applied the Illumina MiSeq sequencing platform based on the amplification of fungal ribosomal ITS2 region to analyze fungal endophytic communities of two oak species (Quercus mongolica and Q. serrata) with different oak wilt disease susceptibilities in Korea. The results showed a total of 230,768 sequencing reads were obtained and clustered at a 97% similarity threshold into 709 operational taxonomic units (OTUs). The OTUs of Q. serrata were higher than that of Q. mongolica with the number of 617 OTUs and 512 OTUs, respectively. Shannon index also showed that Q. serrata had a significantly higher level of fungal diversity than Q. mongolica. Total of OTUs were assigned into 5 fungal phyla, 17 classes, 60 orders, 133 families, 195 genera, and 280 species. Ascomycota was the dominant phylum with 75.11% relative abundance, followed by Basidiomycota with 5.28%. Leptosillia, Aureobasidium and Acanthostigma were the most abundant genera detected in Q. serrata with the average relative abundance of 2.85, 2.76, and 2.19%, respectively. On the other hand, Peltaster, Cladosporium and Monochaetia were the most common genera detected in Q. mongolica with the average relative abundance of 4.83, 3.03, and 2.87%, respectively. Our results indicated that fungal endophytic communities were significantly different between two oak species and these differences could influence responses of host trees to oak wilt disease caused by Raffaelea quercus-mongolicae.

Essential oils have insecticidal activity against several insects and are composed of numerous compounds. This study investigated the insecticidal effects of the Thuja occidentalis L. (Cupressaceae) essential oil, terpinyl acetate, and bornyl acetate against the peach aphid [Myzus persicae (Sulzer)]. The insecticidal effect of essential oils on three Cupressaceae plants was highest in T. occidentalis. The Thuja occidentalis essential oil was extracted by steam distillation, and the optimum conditions were found. The GC-MS profiling of essential oil components extracted from T. occidentalis leaves identified 16 volatile compounds. The main components were α-thujone (16.58%), β-myrcene (14.62%), bornyl acetate (9.31%), and terpinyl acetate (8.52%). As a result of the metabolite profiling of three Cupressaceae plants, terpinyl acetate and bornyl acetate were present in large amounts in all of the essential oils, and they had an acetate structure, so it was estimated that they had insecticidal activity. The insecticidal activity of these two compounds was stronger than the other individual monoterpene compounds. The addition of surfactants to the terpinyl acetate and bornyl acetate showed strong insecticidal activity. Terpinyl acetate and bornyl acetate can be used as environmentally friendly insecticidal-active compounds.

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.

Since 2006 there has been a decline in Colorado blue spruce (CBS; Picea pungens) planted as landscape trees and for Christmas tree production throughout the Lower Peninsula of Michigan. This decline is characterized by a slow loss of needles in the lower portion of the tree starting at branch tips, followed by entire branch dieback, which progresses upward over several years. This dieback has been linked to shallow branch cankers visible in the phloem when the bark layer is removed. Isolates in the fungal genus Diaporthe have been consistently isolated from lesion margins on symptomatic branches. Before the initial reports of declining CBS in landscape and Christmas trees, Diaporthe was known only as a nursery disease of CBS. To determine the species of Diaporthe linked to the decline of CBS in Michigan, seven gene regions were sequenced from a collection of Diaporthe isolates collected in 2011 through 2018 from CBS and other coniferous hosts. Subsequent phylogenetic analyses indicated that Diaporthe eres and a novel Diaporthe clade were present on symptomatic CBS in Michigan. The new species D. brevicancria nov. is described, and Koch’s postulates were confirmed for D. brevicancria nov. and D. eres. D. brevicancria nov. produced the largest cankers in greenhouse pathogenicity trials, and dual inoculations of D. brevicancria nov. and D. eres produced intermediate cankers.

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.