Termite Research Articles

Circadian Rhythms of Locomotor Activity Mediated by Cryptochrome 2 and Period 1 Genes in the Termites Reticulitermes chinensis and Odontotermes formosanus.

Locomotor activity rhythms are crucial for foraging, mating and predator avoidance in insects. Although the circadian rhythms of activity have been studied in several termite species, the molecular mechanisms of circadian rhythms in termites are still unclear. In this study, we found that two termite species, R. chinensis and O. formosanus, exhibited clear circadian rhythms of locomotor activity in constant darkness along with rhythmically expressed core clock genes, Cry2 and Per1. The knockdown of Cry2 or Per1 expression in the two termite species disrupted the circadian rhythms of locomotor activity and markedly reduced locomotor activity in constant darkness, which demonstrates that Cry2 and Per1 can mediate the circadian rhythms of locomotor activity in termites in constant darkness. We suggest that locomotor activity in subterranean termites is controlled by the circadian clock.

Effects of thermal treatment and weathering in the resistance against termites of a fast-growing pine wood

Considering the limited existing literature on the combined effects of thermal treatment and weathering on the resistance of fast-growing pine wood to subterranean termites, this work deals with the resistance against subterranean termites of a thermally treated and weathered fast-growing pine wood. The pine wood was thermally treated at variable temperatures (c.a. 180 ºC, 200 ºC, and 220°C) for 2 h and then exposed to artificial weathering for three months. Chemical, hygroscopic, thermal, mechanical, colorimetric, biological, and morphological characteristics were evaluated. Compared to the untreated wood, as expected, the thermal treatments yielded wood parts with improved thermal, hygroscopic and colorimetric features. The thermal treatment also helped for retaining the thermal stability, volumetric hydrophobicity, color, and roughness of the pine wood exposed to the weathering. Previous changes ascribed to the weathering process did not affect the damages attributed to the termites attack, although that wood treated at 180 ºC presented an increased resistance against the termites deterioration.

Silver Nanoparticles and Chitosan Oligomers Composites as Poplar Wood Protective Treatments against Wood-Decay Fungi and Termites

This study focuses on Populus ×euramericana (Dode) Guinier, a globally distributed fast-growing tree. Despite its valuable wood, it exhibits low durability. The aim of this study was to assess the efficacy of a binary composite comprising silver nanoparticles (AgNPs) and chitosan oligomers (COS) in protecting P. ×euramericana ‘I-214’ wood against degradation caused by xylophagous fungi and termites through vacuum-pressure impregnation. The test material was carefully selected and conditioned following the guidelines of EN 350:2016, and impregnation was carried out in accordance with EN 113-1:2021. Five concentrations of AgNPs–COS composites were utilized. Biodeterioration resistance was evaluated based on EN 350:2016 for white (Trametes versicolor (L.) Lloyd) and brown (Coniophora puteana (Schumach.) P.Karst.) rot fungi, and EN 117:2012 for subterranean termites (Reticulitermis grassei Clément). The durability class and use class were assigned following EN 350:2016 and EN 335:2013, respectively. In comparison to the untreated control, the binary solution at its highest concentration (AgNPs 4 ppm + COS 20 g·L−1) demonstrated a notable reduction in weight loss, decreasing from 41.96 ± 4.49% to 30.15 ± 3.08% for white-rot fungi and from 41.93 ± 4.33% to 27.22 ± 0.66% for brown rot fungi. Furthermore, the observed termite infestation shifted from “heavy” to “attempted attack”, resulting in a decrease in the survival rate from 53.98 ± 10.40% to 26.62 ± 8.63%. Consequently, the durability classification of P. ×euramericana I-214 witnessed an enhancement from “Not durable” to “Slightly” and “Moderately durable” concerning decay fungi and termites, respectively. These findings expand the potential applications of this wood and substantiate the advantages of employing this environmentally friendly treatment.

Weight and protozoa number but not bacteria diversity are associated with successful pair formation of dealates in the Formosan subterranean termite, Coptotermes formosanus.

New colonies of Formosan subterranean termites are founded by monogamous pairs. During swarming season, alates (winged reproductives) leave their parental colony. After swarming, they drop to the ground, shed their wings, and male and female dealates find suitable nesting sites where they mate and become kings and queens of new colonies. The first generation of offspring is entirely dependent on the nutritional resources of the founder pair consisting of the fat and protein reserves of the dealates and their microbiota, which include the cellulose-digesting protozoa and diverse bacteria. Since termite kings and queens can live for decades, mate for life and colony success is linked to those initial resources, we hypothesized that gut microbiota of founders affect pair formation. To test this hypothesis, we collected pairs found in nest chambers and single male and female dealates from four swarm populations. The association of three factors (pairing status, sex of the dealates and population) with dealate weights, total protozoa, and protozoa Pseudotrichonympha grassii numbers in dealate hindguts was determined. In addition, Illumina 16S rRNA gene sequencing and the QIIME2 pipeline were used to determine the impact of those three factors on gut bacteria diversity of dealates. Here we report that pairing status was significantly affected by weight and total protozoa numbers, but not by P. grassii numbers and bacteria diversity. Weight and total protozoa numbers were higher in paired compared to single dealates. Males contained significantly higher P. grassii numbers and bacteria richness and marginally higher phylogenetic diversity despite having lower weights than females. In conclusion, this study showed that dealates with high body weight and protozoa numbers are more likely to pair and become colony founders, probably because of competitive advantage. The combined nutritional resources provided by body weight and protozoa symbionts of the parents are important for successful colony foundation and development.

Feeding cessation after feeding on 20-hydroxyecdysone in the Formosan subterranean termite.

To control subterranean termite pests, chitin synthesis inhibitor (CSI) baits have been widely applied. Despite CSI baits having low impacts on the environment, they require a lengthy time period to eliminate colonies. 20-hydroxyecdysone (20E) was proposed to speed up the baiting process as it showed faster mortality than CSI baits. However, the efficacy of 20E has previously not been tested at the colony level prior to applying in the field. We compared the effect of 20E, 20E + noviflumuron, noviflumuron and untreated control using colonies of Coptotermes formosanus. Our result revealed that both 20E and 20E + noviflumuron did not accelerate colony elimination and termite activity remained relatively stable during the observation periods. To determine the limited effects of 20E, we further investigated feeding duration and consumption amount of 20E with different concentrations (control, 100 and 1000 ppm) for 10 days. Termites ceased feeding after 1 day in 100 and 1000 ppm treatment and 100% mortality was observed within 10 days in 1000 ppm 20E, while mortality in the 100 ppm 20E treated group was much lower than that in the 1000 ppm group. Furthermore, no termites molted in the control and termites died from hyperecdysonism in 1000 ppm 20E treatment, whereas about 20% of termites molted in 100 ppm 20E. This study demonstrated that 20E may not be suitable as a sole active ingredient to accelerate elimination of a subterranean termite colony, while CSI baits and lower concentrations of 20E may reduce the lengthy time period in colony elimination. © 2023 Society of Chemical Industry.

Macro Invertebrate Diversity in Different Land Use System and Soil Fertility Status in Relation to Macro Invertebrate Distribution in Shashogo District, Hadiya Zone, Southern Ethiopia

Invertebrate species are predominant in the food webs and among the ecosystem engineers associated with agriculture. They have a major influence on productivity and therefore play a key role in food security. The objective of the present study is to evaluate the ecological role of soil macro invertebrate diversity for maintenance of soil fertility in Shashogo District, Hadiya zone, Southern Ethiopia. Both field and laboratory work were applied during investigation of the study. Invertebrate’s diversity was identified and Soil samples were collected from different sites and evaluated for soil fertility status. The physico-chemical analysis; organic carbon content, total nitrogen, available phosphorous, available K, soil pH, soil texture, sodium etc… was analyzed. The main soil macro invertebrates identified were Termites ( order Isoptera), Beetles (order Coleoptera), Wasps (Hymenoptera), Millipedes (order diplopoid), Centipedes (chilopoda), Ants (Hymenoptera) and Earthworm (order Opisthopora). The average selected chemical properties of the soil were Soil PH (5.60), Total Nitrogen (0.23), and Organic carbon (2.44), Phosphorus (2.63), Calcium (22.73), Potassium (0.376) and Sodium (0.096). There is significant association between soil macro invertebrate groups and selected soil physical and chemical properties. To conserve soil resources, it needs highest attention of policy makers as well as land use planners to concentrate their efforts on land management strategies based on land use system.

Insulation Materials Susceptibility to Biological Degradation Agents: Molds and Subterranean Termites

Insulation materials are fundamental for decreasing energy losses and guaranteeing thermal and acoustic comfort in buildings, which may significantly contribute to decreasing the energy consumption related with poor thermal building conditions. These insulation materials should have a low susceptibility to biological degradation agents to decrease the risks of degradation of other construction materials, as well as decrease possible health risks related with the development of noxious biological degradation agents regarding indoor air quality, for example, or decrease possible structural risks posed by those agents. The present study aimed at evaluating the susceptibility of several insulation materials to mold growth and subterranean termites’ attack. Insulation materials, including expanded polystyrene (EPS), mineral wool (MW), and expanded cork agglomerate (ICB), were tested against mold development, using maritime pine as a control. Three types of inoculations were made: (1) natural indoor inoculation; (2) artificial inoculation using Aspergillus niger and Penicillium funiculosum; and (3) artificial inoculation using Aureobasidium pullulans. The susceptibility of the insulation materials referred to, plus wood/glass fiber (WGF), was evaluated for two subterranean termite species: Reticulitermes grassei and Reticulitermes flavipes. The expanded cork agglomerate showed a higher susceptibility to molds than the other insulation materials tested. The remaining materials revealed a good performance, showing no growth or traces of growth of molds. All the materials tested showed susceptibility to subterranean termites, with both species being able to cross them to obtain access to the wood. However, wood/glass fiber showed a negative effect, which translated into lower survival rates and attack degrees of the wood. Some tested materials showed a good resistance to the development of biological degradation agents, namely an organic material (coconut fiber), a composite of organic and inorganic materials (WGF), and an inorganic material (EPS). These results indicate that it is possible to pursue the development of innovative and effective insulation materials with a low susceptibility to biological degradation agents, regardless of their organic or inorganic origin.

Novel moisture retaining dustable powder containing Steinernema abbasi effectively controls damage of subterranean termite in wheat and chickpea

The application of biocontrol agents in farm operations for pest control programs is gaining priority and preference globally. Effective delivery, infectivity of the biocontrol agents, and quality shelf-life products containing these bioagents are vital parameters responsible for the success of biopesticides under field conditions. In the present study, moisture-retaining bio-insecticidal dustable powder formulation (SaP) of Steinernema abbasi (Sa) infective juveniles (IJs) was developed and assessed for its shelf life, physicochemical profile, and bio-efficacy against subterranean termite under field conditions. Formulation exhibited free-flowing character, with pH of 6.50–7.50, and apparent density in the range 0.50–0.70 g cm−3. The bioefficacy study for two rabi seasons (2020–2021, and 2021–2022) in wheat and chickpea grown in an experimental farm heavily infested with subterranean termites (Odontotermes obesus) revealed a significant reduction in plant damage due to pest attack in formulation-treated plots, monitored in terms of relative number of infested tillers in wheat and infested plants in chickpea fields. The reduced damage to the crop caused by termite was reflected in the relative differences in the growth and yield attributes as well. The study establishes the potential of the developed product as a biopesticide suitable for organic farming and integrated pest management operations.

Phylogenetic analyses of Reticulitermes (Blattodea: Rhinotermitidae) from California and other western states: multiple genes confirm undescribed species identified by cuticular hydrocarbons.

Subterranean termites in the genus Reticulitermes Holmgren 1913 are among the most economically important wood-destroying pests in the western United States. Yet, there remains uncertainty regarding the taxonomy and biology of the species in this genus. The 2 species described as having distributions in this region are the western subterranean termite, Reticulitermes hesperus Banks, and the arid land subterranean termite, Reticulitermes tibialis Banks. Taxonomic studies utilizing cuticular hydrocarbon (CHC) profiles, agonistic behavior, flight phenology, and mitochondrial DNA (mtDNA) suggested that R. hesperus is a species complex comprised of 2 or more sympatric, yet reproductively isolated species. To further delineate these taxa, we examined multiple genes from samples of Reticulitermes collected in the western United States. Alates collected after recent spring and fall mating flights, as well as previously collected workers, were subjected to CHC phenotyping and DNA sequence analyses that targeted mitochondrial cytochrome oxidase subunit II (COII), mitochondrial 16S rRNA, and nuclear Internal Transcribed Spacer 1 and 2 (ITS1 and 2). Phylogenetic analyses conducted also included published sequences of other putative western Reticulitermes species. Results suggest that at least 5 species of Reticulitermes may be present in California and that Reticulitermes in Arizona consistently group into multiple clades, including samples previously identified as R. tibialis in a sister clade. These analyses further support the species status of qualitatively different CHC phenotypes and that alates swarming in spring vs. fall are reproductively isolated species.

Acarine species associated with subterranean termites (Blattodea, Termitidae)

Ten species of mites were found associated with three species of termites, viz, Odontotermes obesus Rambur, 1842, O. feae Wasmann, 1896 and Nasutitermes gardneri Snyder, 1933. The collected mite species conformed to nine genera, four families and two orders. Among the ten species collected, nine of them were from the order Sarcoptiformes and cohort Astigmatina, while only one belonged to the order Trombidiformes. Seven species collected conformed to the family Acaridae. All mite species exhibited a phoretic relationship with their respective host insects. One adult mite, Premicrodispus paramaevi Hosseininaveh and Hajiqanbar, 2015 and nine deutonymphs were collected and described.

Nitrogen fixation in different termite lineages and diets

Abstract Nitrogen fixation is often cited as an important nitrogen source for termites. However, the rate of nitrogen fixation between experiments and termite species is highly variable due to termite diversity and sampling limitations. New evidence suggests that subterranean termites (Coptotermes formosanus Shiraki) (Blattodea, Rhinotermitidae) seek alternative dietary nitrogen sources for colony growth and development. This study compares N2 fixation rates and nitrogenase gene expression rates to a diverse assemblage of feeding groups. It was observed that nitrogenase expression was much higher in one-piece nesting termites from the family Kalotermitidae which lack access to soil. On the other hand, subterranean termites from the family Rhinotermitidae fix nitrogen at much lower rates, not differing from ambient nitrogenase activity in soil.

α-Terpineol affects social immunity, increasing the pathogenicity of entomopathogenic nematodes to subterranean termites (Isoptera)

Biocontrol of subterranean termites is largely impeded by their social immune responses. Studies on biocontrol agents combined with natural insecticides and their possible effects on the immune defense mechanisms of termites are limited. In this study, we investigated the effects of a combined biocontrol strategy using a plant-derived insect ATPase inhibitor, α-terpineol, with the entomopathogenic nematodes (EPNs) Steinernema carpocapsae against the subterranean termite Coptotermes formosanus Shiraki. Survival assays showed that even a low lethal concentration of α-terpineol significantly increased the EPNs-induced virulence in C. formosanus. α-terpineol treatment majorly inhibited the activity of Na+- K+- ATPase, which disturbed the EPNs-induced enhancement of locomotor activity and grooming behavior in termites treated with the combined strategy. Furthermore, the combination treatment had a synergistic inhibitory effect on innate immune responses in C. formosanus, which were measured as changes in the expression of immune-related genes and activities of immune system enzymes. In conclusion, α-terpineol can weaken the immune defense of termites against EPNs at low lethal concentrations, and is a suitable non-synthetic insecticide to prove the biocontrol efficiency of EPNs on C. formosanus. This study provides a theoretical basis and technical reference for a novel biocontrol strategy that promises to overcome the problems of host immune defense in termites.

AKTIVITAS ANTIRAYAP DARI EKSTRAK METANOL GUBAL KAYU GAHARU BUAYA (Aetoxylon sympetalum) TERHADAP RAYAP TANAH (Coptotermes sp.) (ANTITERMITE ACTIVITY OF METHANOL EXTRACT AGARWOOD BUAYA (Aetoxylon sympetalum) ON SUBTERRANEAN TERMITES (Coptotermes sp.))

Agarwood buaya (Aetoxylon sympetalum) is a Kalimantan endemic plant whose utilization has not been optimal. This plant has potential as an anti-termite, one of which is sapwood. This study aims to determine the content of secondary metabolites from the results of phytochemical screening, components of agarwood buaya sapwood based on GC-MS analysis fraction n-hexane and anti-termite activity against subterranean termites (Coptotermes sp.). Research that has been done is divided into four steps, maceration and fractionation, phytochemical screening, GC-MS analysis, and testing the activity of termites using a forced feeding test method. Crude methanol extract from 1 kg of dried agarwood buaya sapwood was 240.787 g (24.0787%), consisting of 0.8339% n-hexane fraction, 86.3663% chloroform fraction, and 0.7571% methanol fraction. The results of phytochemical screening on agarwood buaya sapwood extract showed that it contained flavonoid, terpenoid, steroid, and phenolic compounds. Identification of the components of agarwood buaya sapwood fraction n-hexane through GC-MS yielded compounds a4-chloro-6-methoxy-2-methylquinolin-8-amine (10.33%), stigmasterol among other (5.94%), n-hexa-decanoic acid (3.2%), 6-octa-decenoic acid (2.99%), and 1,2-Benzene-diol, 3,5-bis(1,1-dimethyl-ethyl) (2.01%). Termite activity test was carried out for 3 days with variations in the concentration of 0% (negative control), 0.1%, 0.2%, 0.3%, 0.4% (w/v), and 0.25% (v/v) (fibronil as positive control). The results of anti-termite testing show the most active fraction was the methanol fraction (LC50 0.146%) followed by the chloroform fraction (LC50 0.167%), methanol crude extract (LC50 0.192%), and the n-hexane fraction (LC50 0.208%).

A comparison between above-ground bait stations and experimental caulk baits for elimination of field colonies of the Asian subterranean termite, Coptotermes gestroi (Blattodea: Rhinotermitidae).

Survey stakes and in-ground (IG) stations have failed to intercept underground tunnels of the Asian subterranean termite, Coptotermes gestroi (Wasmann), in southeastern Florida, rendering nearly useless the IG bait station that is the main tool of commercial baiting systems. When placed over an active infestation, above-ground (AG) bait stations were readily fed on by C. gestroi, resulting in colony elimination. A new experimental type of AG bait application being studied is an injectable caulk bait. In this study, we compared the efficacy of AG bait stations and an experimental AG caulk bait against field colonies of C. gestroi. Following the applications of AG bait stations at 3 sites with infested houses and trees, C. gestroi colonies were eliminated 7.1-28.1 wk later. The experimental AG caulk bait was applied at 7 sites including 4 houses, 2 office buildings, and 1 docked sailboat. Colony elimination times at caulk bait sites ranged from 3.1 to 13.6 wk, but there was no statistical difference in mean colony elimination time between AG station bait sites (17.4 ± 10.5 wk) and AG caulk bait sites (8.4 ± 3.8 wk). This study showed that AG caulk bait applications were equally efficacious in eliminating existing C. gestroi in structures as AG bait stations and will offer another tool for termite control professionals to better manage subterranean termites including C. gestroi.

Characteristics of Simalambuo (Lophopetalum sp.) wood from Nias Island, North Sumatra Province, Indonesia

Abstract. Iswanto AH, Amanda DW, Gea S, Susilowati A, Fatriasari W, Darwis A, Lubis MAR, Sucipto T, Syahidah, Subekti N, Hartono R, Sutiawan J, Hidayat W, Kim NH. 2023. Characteristics of Simalambuo (Lophopetalum sp.) wood from Nias Island, North Sumatra Province, Indonesia. Biodiversitas 24: 4193-4201. Simalambuo (Lophopetalum sp.) wood is commonly used for construction materials in Nias Island, North Sumatra Province especially in the aftermath of the devastating earthquake that affected the region. However, information regarding the fundamental characteristics of this wood has not been available. Therefore, this research aimed to evaluate the basic properties of Simalambuo wood, such as its physical, mechanical, chemical, and natural durability. The destructive method was used to determine the physical and mechanical parameters (i.e., specific gravity, moisture content, shrinkage, MOE, MOR, and hardness) using a small clear specimen sample under the BS 373 standard (1957). The chemical components of wood (i.e., holocellulose, cellulose, lignin, extractives) were analyzed using a variety of methods, including CRC Press methods, LAP NREL 003 standard, and TAPPI. Meanwhile, the SNI 7207-2014 standard was utilized to evaluate its resistance against subterranean termites. The results showed that Simalambuo wood has an average specific gravity of 0.42 and a T/R ratio of 1.78. Based on its specific gravity, the wood is classified within the strength class III-IV. It also exhibits a reduced cellulose and extractive content, along with a higher proportion of lignin. In terms of durability, it is classified as class IV, implying non-resistance to termites’ attack and necessitating wood preservation treatment for its practical application. The findings of this study suggest the application of this wood is recommended for light construction, furniture, and other functions, but not for heavy construction.

Exploring the Nutritional Potential of Microtermes obesi Consumed by the Ethnic Communities of Baksa District, Assam, India

The practice of eating insects is widespread throughout the world. The use of edible insects in animal feed and human diet is being advocated on a universal scale as an alternative source of protein, lipids and micro - nutrients which is correlated with global food security. Termites are nutritionally endowed eusocial insects belonging to the order Isoptera. Microtermes obesi, a termite species has been a part of traditional cuisine among different communities of Assam. Therefore, the present study was assigned to investigate the presence of nutrient composition and antioxidant properties of M. obesi, an edible termite species collected from Baksa district of Assam. In the current investigation, the nutritional values recorded from M. obesi adult comprised of 7.68±0.02% moisture content, 45.15±1.97g/100gm crude protein, 8.40±2.05 g/100gm crude fat, 28.76±1.31 mg/100gm Na, 22.86±2.19 mg/100gm K, 108.36±2.18 mg/100gm Fe, 58.09±1.38 mg/100gm Ca, 20.47±3.15 mg/100gm S, and 132.88±2.15 mg/100gm P. The biochemical contents such as total phenolic, total flavonoid and DPPH radical scavenging activity are recorded as 108.17±2.43 mg gallic acid equivalent (GAE)/100g, 58.06±3.26 mg quercetin equivalent (QE)/100g and 84.90±2.15% respectively. Findings of this study demonstrated the presence of rich nutritional and high antioxidant qualities in M. obesi termite species and also provided scientific validation on the entomophagy practice of M. obesi which can be consumed as alternative source of nutrient in animal feed with potential health benefits.

A method for estimating colony size using queen fecundity in termites under field conditions.

Colony size in social insects is one of the most important factors in shaping their self-organized system. It affects a wide variety of traits such as foraging and defense strategies, social immune responses, the degree of polymorphism, and reproductive output. However, colony size estimation of subterranean termites in the field has been challenging, due to their extremely cryptic biology and multiple site-nesting behavior. Since natural selection favors workers that maximize the number of their siblings, the amount of egg production may reflect the number of workers in the colony. Here, we report a method for inferring colony size in the field using total egg production in each colony from a subterranean termite, Reticulitermes speratus. Our investigation of field colonies revealed that the body weight of queens reaches a peak and had the largest variance in June and July and accurately predicts the number of eggs laid by the queen per 24 h. Using laboratory-reared colonies, we found that the total egg production in each colony is proportional to the number of workers. We also estimated the colony size of 198 field colonies and found that the median and maximum colony size was 24,500 and 451,800 workers per colony. The method for inferring colony size presented here may also be applicable to termite species with a clear seasonality in egg production. The colony size estimate will contribute to understanding the life history strategies and social systems of termites.

Prescribed Burning Alters Insects and Wood Decay in a Sagebrush-Steppe Rangeland in Southwestern Idaho, United States

Prescribed fall burning is commonly used worldwide on rangeland sites to enhance vegetation resources and restore disturbed ecosystems, but little is known about how it may alter microbial communities and insect activities. We used two site treatments (low- to moderate-burn severity plots and unburned control plots) at a high-elevation (2 100 m above sea level) shrub-steppe rangeland site. Four yr after the prescribed burn, captured insects primarily consisted of Coleoptera (beetles), Hymenoptera (ants, bees, and wasps), and Orthoptera (grasshoppers and crickets) species with similar or greater numbers captured on burned plots as compared with unburned plots. We used wood stakes to assess microbial population changes. Aspen (Populus tremuloides Michx.) and pine (Pinus taeda L.) wood stakes were placed horizontally on the soil surface and vertically into the mineral to determine microbially altered wood decay rates. In mineral soil, mass loss (wood decay) of both aspen and pine increased significantly in the burned plots after 5 yr. Surface aspen also had increased decay in the burned plots, but pine surface stakes were unaffected. Surprisingly, at this high-elevation site we also found subterranean termites (Reticulitermes tibialis Banks) feeding on both stake species, with greater numbers on aspen stakes in burned plots leading to greater wood mass loss and organic matter turnover rates. Our results suggest that that fall prescribed burning can enhance insect numbers and microbial decay in sagebrush-steppe ecosystems. Understanding these changes can help land managers predict the influence of fall prescribed burning operations on soil biological properties and insect communities.

Resistance of Chip Block Pallet from Teak Wood Particle against Decay Fungi and Subterranean Termites

Wood biomass such as sawdust, particles, and chip obtained wood industry can be used as raw material for chip block pallets (CBP). This study evaluated the resistance of chip block pallets made from teak-sawn waste and polyurethane adhesive against decay fungi (white-rot and brown-rot fungi) and subterranean termites. The CBPs with dimensions of 9 × 9 × 9 cm and a target density of 0.6 g/cm3 were cold pressed at 9.8 MPa for 4 h using several polyurethane concentrations and composition of particle sizes. The termite and decay resistance tests were conducted following JIS K 1571 2004. The results showed that CBP treated with different polyurethane concentrations and composition of particle sizes was resistant to subterranean termite attacks. However, the CBP manufactured were not resistant to white-rot and brown-rot fungi attacks, showing more than 3% mass loss percentage. Considering the efficiency of polyurethane use, the study suggested the best content for using polyurethane in the manufacture of CBP is 4.5% with a particle size composition of 50 (4-14 mesh): 50 (> 60 mesh). Keywords: Biodeterioration, chip block pallet, polyurethane, teak wood particles

Natural durability of some hardwoods imported into Korea for deck boards against decay fungi and subterranean termite in accelerated laboratory tests

Natural durability of some hardwoods imported into Korea for deck boards against decay fungi and subterranean termite in accelerated laboratory tests