Termite Research Articles

Decay, mold, and termite resistance of high-density fiberboard from wood and chicken feather fibers

The decay, mold, and termite resistance of high-density fiberboard (HDF) formed using combinations of wood and chicken feather fibers (CFF) bonded with polyurethane resin was investigated. Laboratory and underground field exposure tests showed that HDF containing 50% to 100% CFF by weight were moderately to highly resistant to the white-rot fungus Pycnoporus sanguineus (L.) Murrill and the subterranean termite Coptotermes gestroi Wasmann. Moderate to heavy mold growth was observed on HDF containing 25% to 100% CFF when inoculated with a mixed strain of Aspergillus niger, Penicillium chrysogenum, and Trichoderma viride. In general, HDF consisting of wood fibers and CFF was resistant to decay and subterranean termite but susceptible to mold growth. The susceptibility HDF to mold may require the use of a biocide to improve mold resistance.

Efficacy and utility of isocycloseram a novel isoxazoline insecticide against urban pests and public health disease vectors.

Isoxazolines inhibit γ-aminobutyric acid chloride channels in insects and acarids by binding to postsynaptic receptors. This prevents chloride influx, leading to depolarization/hyperexcitation, paralysis, and death. Here, we evaluated the potential utility of a novel isoxazoline, isocycloseram, against several urban insect pests. Isocycloseram was active at low doses against the German cockroach, Blattella germanica (L.)[median lethal dose (LD50) 5-15 ng per insect at 72 h, topical assays]; Argentine ant (Linepithema humile Mayr), Pharaoh ant (Monomorium pharaonis (L.), common bed bug (Cimex lectularius (L.) (approximately 40 mg m-2, residual surface spray); Eastern subterranean termite (Reticulitermes flavipes (Kollar)and Formosan subterranean termite (Coptotermes formosanus Shiraki) (5 μg g-1 w/w, tunneling assays); and mosquito, Anopheles stephensi Liston (120 and 150 mg m-2 treated surfaces, aged indoors for 9 months). Additionally, cockroach gel bait at 1% isocycloseram (w/w) caused 95-100% mortality in German, American (Periplaneta americana (L.), and oriental (Blatta orientalis (L.) cockroaches within 5-14 days. Isocycloseram proved to be active against both laboratory and field populations of German cockroaches at doses lower or equal to those of other chemicals. Ants, bed bugs, and mosquitoes readily acquired lethal doses of isocycloseram from different surfaces treated with formulated products. Given its non-repellent nature, delayed effects, and activity at low rates, isocycloseram can be a very effective compound against subsocial, social, and other human disease vector insect pests. © 2024 Society of Chemical Industry.

Subterranean termites (Coptotermes formosanus [Blattodea: Rhinotermitidae]) colonies can readily intercept commercial inground bait stations placed at label-prescribed distance

Abstract The Formosan subterranean termite, Coptotermes formosanus Shiraki, is both an economically impactful pest and a successful invader. One method of subterranean termite control is baiting. According to the label, baits are installed surrounding the structure at a uniform interval distance of ≈3 m. However, homeowners and pest control professionals are often concerned that termites may bypass bait stations and have access to the structure. To address this concern, we experimentally duplicated field conditions using a large planar arena (3.6 m × 1.1 m) to study the optimal distribution of bait stations based on colony-wide foraging activity. We installed 2 bait stations 3 m apart as per label instructions and introduced C. formosanus colonies to allow them to explore the arena by tunneling through the sand. In this real-scale arena, all termite colonies intercepted a bait station in an average of 21 (± 8 SD) days. We assumed that termites could find bait faster if there were more bait stations by overlaying additional hypothetical baits closer than per label instruction, but the improvement was incremental, requiring 4 times more stations (0.45 m interval) to obtain a significant difference. We also revealed the characteristic behavior after intercepting bait stations, termites created a burst of tunnels that radiated from the bait station. These branching tunnels averaged 16 cm in length, suggesting immediate interceptions of additional auxiliary stations placed within 16 cm of an active station. These findings contribute to our understanding on how subterranean termites intercept inground bait stations.

Assessment of the biological durability of oil palm trunk modified with 1,3-dimethylol-4,5-dihydroxy-ethyleneurea (DMDHEU) following subsequent curing at elevated temperatures

The biological durability of oil palm trunk modified with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) was tested after subsequent curing at elevated temperatures. The resistance against mold, decay fungi, and subterranean termites was examined. Dimethylol dihydroxyethyleneurea-modified OPT demonstrated improved resistance against mold and decay fungi; however, the effect was lesser on subterranean termite attacks. Oil palm trunk modified with 34% DMDHEU and cured at 160 °C exhibited the most effective reduction in mass loss due to biological degradation compared to the untreated controls. High curing temperature (> 180 °C) caused cracks and ruptured the cell walls, exposing the untreated zone of the OPT to biological attack. As a non-biocidal wood modification, homogeneous dispersion of DMDHEU with adequate concentration and curing temperature is important to fully prevent OPT degradation by wood-destroying fungi and termites. These results provide valuable information for technologists to enhance or streamline the experimental design of combined modification with DMDHEU and thermal treatment, supporting their practical goals. It is recommended to continue research on the leaching of DMDHEU-modified OPT to understand the prevailing effect of DMDHEU on the biological durability of OPT, whether it is due to cross-linking or filler dispersion.

How do termite baits work? implication of subterranean termite colony demography on the successful implementation of baits.

In 1995, the launch of the first commercial chitin synthesis inhibitor (CSI) bait led to the transformation of the subterranean termite control industry around the world. Their slow mode of action, which relies on both their ability to be transferred among nestmates and termite molting biology, has made them cost-effective solutions for subterranean termite colony elimination while minimizing the introduction of pesticides into the soil toward an environmentally sustainable strategy. However, despite successful commercial implementations, the acceptance of their use varies within the pest control industry around the world. Notably, the nuanced complexity of how CSI baits lead to colony elimination upon feeding by termite foragers has, in part, remained elusive for the past 3 decades, allowing for long-lasting misconceptions to persist. A recent series of studies has since provided complementary elements of understanding how CSI baits utilize termites' inherent colony demography, behavior, and physiology to trigger colony elimination after a characteristic succession of events within the colony collapse process. I here provide a synthetic overview of subterranean termite colony characteristics when exposed to CSI baits using Coptotermes (Wasmann) (Blattodea: Heterotermitidae) as a primary model system. The changes in colony demography through the colony collapse reflect how the mode of action of CSI baits makes them a prime solution for sustainable subterranean termite pest management. Following decades of innovation, ongoing interactions among termite researchers, bait product manufacturers, and pest management providers must continue to bring solutions to existing and emerging termite pest problems around the world.

Lethal disruption of the bacterial gut community in Eastern subterranean termite caused by boric acid.

The Eastern subterranean termite, Reticulitermes flavipes (Kollar) (Blattodea: Rhinotermitidae), is a significant pest, causing extensive damage to structures that amount to substantial economic losses. Boric acid is widely used for wood preservation due to its stability and broad-spectrum insecticidal properties, yet its impact on termite gut microbiomes and the implications of such effects remain understudied. Our study evaluates the dose-dependent mortality of R. flavipes upon being provided boric acid treated filter papers and investigates the resulting dysbiosis within the termite gut microbiome. Consistent with reports from other insects, mortality increased in a dose-dependent manner, with the highest boric acid concentration (203.7 µg/cm2 of filter paper) significantly reducing termite survival. 16S rRNA gene sequencing of the gut bacterial microbiome revealed notable shifts in composition, indicating boric acid-induced dysbiosis. Aside from an overall decrease in bacterial diversity, the relative abundance of some symbionts essential for termite nutrition decreased in response to higher boric acid concentrations, while several opportunistic pathogens increased. Our findings extend the understanding of boric acid's mode of action in termites, emphasizing its ability to significantly modulate the bacterial symbiont community, which can have dire effects on termite biology. Considering its ability to protect wood from further termite consumption, our study supports the continued use of boric acid and related compounds for termite-resistant treatments for wood.

Aktivitas Antirayap Kulit Batang dan Akar Tumbuhan Kokosan (Lansium domesticum cv Kokossan) Terhadap Rayap Tanah (Coptotermes curvignathus Holmgren)

Kokosan (Lansium domesticum cv Kokossan) is one of the Meliaceae family plants known to produce various compounds with various activities. The Meliaceae family is known to have fruit seeds with a bitter taste that can be utilized as an antifeedant in insects. However, research on the bioactivity and content of secondary metabolites in the roots and bark of kokosan as termiticides against subterranean termites has never been reported. This study aims to determine the content of secondary metabolite compounds and test the anti-termite activity of extracts and fractions of kokosan root and stem bark against Coptotermes curvignathus Holmgren termites. Root and stem bark powder were macerated separately using methanol solvent and then fractionated to obtain n-hexane, dichloromethane, ethyl acetate, and methanol fractions (residue). Each extract and fraction was fed to termites through cellulose paper at a concentration of 5% for 3 days. Based on the results of phytochemical tests on extracts and fractions from the roots and bark of kokosan, it is known to contain alkaloid, flavonoid, terpenoid, and phenolic compound groups. The results of the anti-termite activity test are based on the percentage mortality value obtained by the methanol extract of the most active root with a value of 97.2% and paper weight loss of only 6.92%. In the ethyl acetate fraction of the roots, mortality was 84.4% and paper weight loss was 2.38%, and the n-hexane fraction of the stem bark showed mortality of 87.6% and paper weight loss of 2.20%. The kokosan root obtained has the most active activity against Coptotermes curvignathus Holmgren.

Identification of a colony- and dose-dependent worker aggregation pheromone in the subterranean termite Reticulitermes virginicus

Collective behaviors of social insects are often regulated by pheromones. In subterranean termites, some workers forage for and exploit decaying wood for new food resources while forming tunnels from their nest. Colonizing new food resources requires workers to build and disinfect tunnels and chambers inside the nest and ingest decaying wood; therefore subterranean termite colonies should have mechanisms to establish and maintain groups of workers to perform these functions. Recently, an aggregation pheromone was identified in workers of the termite Reticulitermes speratus, which induces quick attraction of nestmate workers and prolonged aggregation to the site of attraction. In this study, we extended this work to another species of Reticulitermes and identified a worker aggregation pheromone in the termite R. virginicus. GC–MS analysis and bioassays demonstrated that this pheromone consists of 3-octanone, 3-octanol, and palmitic acid and shows a colony-specific, dose-dependent attractant response but not an arrestant response. Furthermore, these pheromone components were most likely emitted from the surface of the body. This suggests that aggregation pheromone composition and function differ significantly among termite species, even within the same genus. This study advances our understanding of the regulatory mechanisms of termite aggregation behavior.

Repellent and toxic effects of indigenous plant seed extracts on fungus-growing subterranean termites (Blattodea: Termitidae)

The indiscriminate use of synthetic pesticides to control fungus-growing termites has led to biological and environmental hazards and has contributed to the development of resistance in these pests. In the search for environmentally safe alternatives, plant-derived biopesticides have been explored as replacements for synthetic insecticides. The present study aims to shed light on the use of naturally occurring anti-termite compounds extracted from the seeds of indigenous plants. Specifically, seed extracts from Moringa oleifera (sohanjna) and Citrullus colocynthis (bitter apple) were tested using methanol and water as solvents in bioassays against fungus-growing subterranean termites. The entomotoxic properties of the methanolic and aqueous extracts from these plant seeds were examined to determine their effects on termite mortality, repellency, and foraging behavior. The results revealed that both plant seed extracts negatively impacted the survival and repellency of termites. C. colocynthis showed better results in terms of termite mortality and had lower LT50 values compared to M. oleifera. However, in terms of tunneling behavior, M. oleifera) showed more significant effects than C. colocynthis. Based on the outcomes of these trials, both C. colocynthis and M. oleifera demonstrated significant potential as effective termiticides. Therefore, it is recommended that these native plant seed extracts be incorporated into termite control strategies.

Preferences of Subterranean Termites (Coptotermes sp) for Monocotyledonous Plants and Dicotyledonous Plants on Mineral Land

Subterranean termites are recognized for their capacity to damage various plant species, regardless of their productivity. These termites can launch attacks with varying degrees of intensity, targeting both trees and living plants, particularly in agricultural settings such as oil palm and rubber plantations, as well as in industrial forests comprising species like pine and eucalyptus. Characterized by its tropical climate, Indonesia exhibits high levels of environmental humidity, warmth, and organic matter in the soil, which further supports termite activity in a study conducted in the Tj. Keliling Village Plantation area of Salapian District, Langkat Regency, ten bait woods were randomly planted in a rectangular plot measuring 12 meters in length and 7 meters in width. The spacing between the rows of bait wood was set at 30 cm, while the distance between individual bait wood columns was 60 cm. A descriptive method was employed for data analysis. The findings revealed varying percentages of damage among different types of bait wood: 10% for Pinang wood, 5% for coconut wood, 18.3% for oil palm wood, 33.3% for durian wood, 73.3% for teak wood, and the highest damage percentage of 77.3% for kapok wood. The attraction of termites to plants situated on mineral soil is attributed to the latter's role in enhancing humidity, which is a critical factor facilitating the rapid growth and proliferation of subterranean termites. Consequently, the intensity of their attacks can occur at any time until appropriate management measures are implemented.

Resistance to Subterranean Termite (Reticulitermes speratus) in Wood Species Used as Members in South Korea’s Major Wooden Building Heritage

Resistance to Subterranean Termite (Reticulitermes speratus) in Wood Species Used as Members in South Korea’s Major Wooden Building Heritage

Novel acrylamide-based baits for effective control of subterranean termites (Blattodea: Rhinotermitidae).

Acrylamide-based bait has super water absorption making it highly attractive to subterranean termites that are lured by wood with high water content. This study investigated the control efficiency of these baits on subterranean termites. In particular, we evaluated the water-absorption capacity, attractiveness to subterranean termites, and control efficiency of these baits on subterranean termites through wooden blocks (Populus deltoides and three types of particleboards). The results indicated a substantial water absorption capacity of acrylamide (70.6%; control: 14.8%) and a strong attraction for feeding subterranean termites (P. deltoides: 198 highest; 81 lowest subterranean termites individuals; combination of neem leaves and walnut shells: 168 highest; 36 lowest subterranean termites individuals). When acrylamide was combined with boric acid at the highest concentration, it resulted in the lowest wood consumption rates (P. deltoides: 24.1%; control: 63.8%, combination of neem leaves and walnut shells: 32.5%; control: 62.1%). In conclusion, this research supports the commercial viability of employing innovative acrylamide-based toxic baits and particleboards for subterranean termite management. © 2024 Society of Chemical Industry.

Death zone minimizes the impact of fipronil-treated soils on subterranean termite colonies by negating transfer effects.

The use of nonrepellent liquid termiticides against subterranean termites has long relied on the assumption that foraging termites in soils could transfer toxicants to nestmates to achieve population control. However, their dose-dependent lethal time can lead to rapid termite mortality in proximity of the treatment, triggering secondary repellency. The current study characterizes the dynamic nature of the "death zone," i.e., the area adjacent to soil termiticides that termites would avoid owing the accumulation of cadavers. Using whole subterranean termite laboratory colonies of Coptotermes gestroi (Wasmann) with 3 × 15 m foraging distances, fipronil was implemented at 1.5 m, 7.5 m, or 12.5 m away from colony central nests, emulating a corrective action against an termite structural infestation. For treatments at 7.5 m and 12.5 m, the death zone stabilized at an average of ~2.56 m away from the treatment after 40 d post-treatment, and colonies suffered as little as 1.5% mortality by 200 d post-treatment. Colonies located 1.5 m away from the treatment minimized the death zone to ~1.1 m and suffered as little as 23.5% mortality. Mortality only occurred within the first few days of treatment from initial exposure, as the rapid emergence of the death zone negated further transfer effects among nestmates over time. In some cases, foraging termites were trapped within the infested structure. While technically nonrepellent, fipronil becomes functionally repellent from the rapid mortality onset near the treatment. Even if diligently implemented to successfully protect structures, surrounding termite colonies are minimally impacted by fipronil soil treatments.

Butylated hydroxytoluene and ethylenediaminetetraacetic acid combined with cedarwood oil as wood treatments for protection from subterranean termites and wood-decaying fungi

Butylated hydroxytoluene and ethylenediaminetetraacetic acid combined with cedarwood oil as wood treatments for protection from subterranean termites and wood-decaying fungi

The morphological diagnosis of 2 economically important subterranean termites in Western Indonesia, Coptotermes curvignathus and Coptotermes gestroi (Blattodea, Rhinotermitidae).

In Indonesia, the control of Coptotermes curvignathus populations as living tree termite pests has been carried out since the early 20th century. Recently, C. curvignathus has been considered the main termite pest and designated as the only species model for wood and wood products resistance tests against subterranean termite attack testing protocol in the Indonesian National Standard (SNI). However, the species distribution range of C. curvignathus has been long questioned as Coptotermes gestroi is commonly reported as a species found in urban areas of Southeast Asian region, particularly in Indonesia. One of the reasons for the species distribution discrepancies is the lack of morphological markers to distinguish both species in the field. Thus, limiting the field inspection effectiveness in termite pest management in Indonesia. This study reexamined and clarified the morphological differences between C. curvignathus and C. gestroi, based on soldier caste. The head shape, mandible shape, and distribution of genal setae on the ventro-anterior head part and pronotum marked the difference between the 2 species. These current results support previous findings of C. curvignathus as the forest dweller while clarifying C. gestroi as the common urban dweller in Indonesia. The putative benefit of morphological features related to the head, mandible, and setae distribution to the defensive adaptation in their common habitat was discussed. Ultimately, the inclusion of C. gestroi into the Indonesian National Standard (SNI) as an alternative species for efficacy tests against subterranean termites is highly recommended.

Prostaglandin A3 regulates the colony development of Odontotermes formosanus by reducing worker proportion

Subterranean termites cause significant economic losses worldwide due to their destruction of agricultural and forest plants. In the past, soil termiticides were commonly used to control subterranean termites because they were effective and affordable. However, due to growing environmental concerns, these harmful substances have become less popular as they cause damage to non-target organisms and lead to environmental contamination. Baits crafted from plants and other easily metabolized compounds serve as excellent alternatives. In this study, we gathered branches from the promising plant, Magnolia grandiflora L. (MGL), along with branches from five other tree species that are potential food for termites. These branches were used as food to observe the population growth of Odontotermes formosanus. Additionally, a mix of branches from all six species was used to feed the control group (MIX). The study results showed that MGL nutrition significantly inhibited worker development, resulting in a significantly lower worker-to-soldier ratio (WSR). Furthermore, LC‒MS/MS analysis revealed that the level of prostaglandin A3 (PGA3) in workers significantly increased when they were under MGL nutrition. Additionally, ICP-MS analysis indicated a significant increase in calcium concentrations in the branches of MGL and combs under MGL nutrition. Moreover, there was a significant increase in peroxidase (POD) activity in workers under MGL nutrition. These findings suggest that the inhibitory effect of MGL nutrition on worker development may be due to excessive PGA3 synthesis, as Ca2+ and POD are involved in the synthesis process of PGs in insects. Subsequent verification experiments strongly support this hypothesis, as the WSR of colonies fed PGA3-added MIX was significantly lower than that of the MIX alone. This study introduces a new concept for developing environmentally friendly biological control methods for O. formosanus and sheds light on the potential role of PGs in termite development.

Biological Deterioration of Wooden Components of Balla Lompoa Ri Galesong in South Sulawesi, Indonesia

Balla Lompoa Ri Galesong, known well as the traditional house of the Takalar Regency, South Sulawesi, has become a historical building in Indonesia. Nowadays, it still functions as a residence for the royal family, a repository for historical artifacts, and a venue for annual cultural performances. Maintaining and protecting buildings from damaging factors is crucial to maintaining their life and function. This research focuses on detecting the damage characteristics of wooden parts of buildings, identifying biological deterioration agents, and assessing the level of infestation. Data collection uses the visual detection method. The results showed that the activities of biodeterioration agents, namely subterranean termites (Microcerotermes serrula), drywood termites (Cryptotermes), powder-post beetles, wood-staining fungi, and wood-decaying fungi found on pillars, windows, doors, walls, floors, and ceiling. Most pillars are targets of attacks by wood-destroying organisms, characterized by the highest attack intensity (70.13%) and the moderate category in the degree of attack (50–74). Understanding and mitigating the damage to historic buildings is critical for implementing effective preventive measures. Keywords: Balla Lompoa Ri Galesong, biodeterioration agents, cultural heritage, wood biodeterioration

Resistance of Wood Plastic Composites Having Silica Filler to Subterranean Termite

Resistance of Wood Plastic Composites Having Silica Filler to Subterranean Termite

Biology and Management of the Formosan Subterranean Termite and Related Species

Biology and Management of the Formosan Subterranean Termite and Related Species

Termiticidal Effects and Morpho-Histological Alterations in the Subterranean Termite (Odontotermes formosanus) Induced by Biosynthesized Zinc Oxide, Titanium Dioxide, and Chitosan Nanoparticles.

Recently, nanoparticles have been widely used in agricultural pest control as a secure substitute for pesticides. However, the effect of nanoparticles on controlling the subterranean termite Odontotermes formosanus (O. formosanus) has not been studied yet. Consequently, this study aimed to evaluate the effectiveness of some nanomaterials in controlling O. formosanus. The results showed that zinc oxide nanoparticles (ZnONPs), titanium dioxide nanoparticles (TiO2NPs), and chitosan nanoparticles (CsNPs) biosynthesized using the culture filtrate of Scedosporium apiospermum (S. apiospermum) had an effective role in controlling O. formosanus. Moreover, the mortality rate of O. formosanus after 48 h of treatment with ZnONPs, TiO2NPs, and CsNPs at a 1000 µg/mL concentration was 100%, 100%, and 97.67%, respectively. Furthermore, using ZnONPs, TiO2NPs, and CsNPs on O. formosanus resulted in morpho-histological variations in the normal structure, leading to its death. X-ray diffraction, UV-vis spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, dynamic light scattering, energy dispersive spectroscopy, and the Zeta potential were used to characterize the biosynthesis of ZnONPs, TiO2NPs, and CsNPs with strong activity against O. formosanus termites. Overall, the results of this investigation suggest that biosynthesized ZnONPs, TiO2NPs, and CsNPs have enormous potential for use as innovative, ecologically safe pesticides for O. formosanus control.