Termite Mortality Research Articles

Efficacy of Melia azedarach leaf extract in different solvents against Heterotermes indicola Wasmann (Blattodea: Rhinotermitidae) using non-durable wooden blocks under laboratory and field conditions

Hetertermes indicola Wasman (Blattodea: Rhinotermitidae) is a highly wood-destructive termite species in the urban settings of Pakistan. This study evaluated the biocidal action of Melia azedarach leaf extract in different solvents on H. indicola by conducting choice and no-choice feeding deterrence assays using impregnated palatable wood under field and laboratory conditions. Dose-dependent and time-dependent trends were observed in the leaf extracts of M. azedarach at different concentrations (500, 1000, and 1500 ppm) using solvent water and methanol with 80–100 % termite mortality after 6 days of exposure. A key outcome was the higher termiticidal efficacy of methanolic extract compared to aqueous extract under both field and laboratory conditions. The LC50 values of 358 ppm for methanol and 466 ppm for aqueous extract after 15 days in a laboratory no-choice experiment exhibit a quantitative measure of chinaberry leaf extract toxicity. A significant reduction in mean percent weight loss (8.26 %) of treated wood with 1500 ppm of M. azedarach leaf extract in methanol was observed under field conditions. In conclusion, triterpenoids and phytol present in methanolic leaf extract demonstrated higher efficacy in both lab and field conditions making a solid foundation for the further development of natural wood preservatives. Since they induced rapid lethargic conditions in termites and digestive toxicity which leads to minimum loss of treated wood.

Study on the role of RPL23 gene in active immunity of termite Reticulitermes chinensis against Metarhizium anisopliae

Ribosomal proteins are considered to be involved in the immunity of different animals against pathogens. The protein level of RPL23 increased after fungal infection in termites, but how it influence active immunity in termites is unknown. The role of RPL23 gene was studied to evaluate its impact on active immunity of termite Reticulitermes chinensis against entomopathogenic fungus (EPF) Metarhizium anisopliae. The RPL23 gene fragment (414 bp) was cloned and phylogenetic analysis revealed that it’s very close to termite Coptotermes formosanus. Expression of RPL23 gene was significantly higher in abdomen as compared to thorax and head. Silencing RPL23 gene had no significant impact on the frequency and time of allogrooming towards fungus exposed termites from nestmates, which showed that nestmates acquired spores from infected termites through allogrooming. Expression of immune genes (GNBP1, GNBP2 and phenoloxidase) and apoptosis related genes (TNF-α, caspase 1, caspase 3 and caspase 8) decreased significantly in nestmates of fungus-treated termites after silencing of RPL23 gene as compared to control. Antifungal activity and survival of RPL23 silenced nestmates of fungus-treated termites also decreased. To sum up, this study found that silencing of RPL23 gene broke the active immunity against M. anisopliae infection, reduced the antifungal activity of termites, weakened cell apoptosis, and led to increased mortality of termites, which may help to find a potential alternative for chemical insecticides to control termites.

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.

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.

Bioactive enhancement of PVA films through CNC reinforcement and Ficus auriculata fruit extract: A novel synthesis for sustainable applications

Cellulose nanocrystals (CNCs) have received immense interest lately as a potential nanomaterial because of their excellent mechanical and biological properties. This investigation aims to formulate a composite coating made of polyvinyl alcohol (PVA), CNCs, and a methanolic extract from the dried leaves and fruit of the fig tree (Ficus auriculata) (FAE). A sequential procedure to get CNCs included alkaline and acid hydrolysis, sonication, and suitable methods for purification. Analytical techniques like X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to study the CNC-loaded films. Thermogravimetric analysis (TGA) of composites revealed superior thermal stability of the CNC-reinforced films versus control, evident from higher degradation temperatures, indicating desirable environmental resistance of proposed coatings for wood surfaces. The termite control was made more effective through synergistic use of a combination of CNCs, PVA, and FAE with proven insecticidal properties. The composite material was examined for its anti-termite resistance and termite mortality rate, and demonstrated that when used together, CNCs, PVA, and FAE were collectively and synergistically more effective at keeping termites away. The findings of this study demonstrate that the evolved composite could be used to develop anti-termite products that are environmentally benign and respond well. Synthesized composites also demonstrated significant antibacterial activity. Among all films, a combination of 0.7 % extract in PVA displayed excellent results with 26 and 28 mm diameter for growth inhibition zone for Gram-positive bacteria whereas 26 mm for both negative bacterial strains. The findings suggest a potential use of this composite as a sustainable, environmentally resistant, and eco-friendly alternative for termite/bacterial control in various building materials and wood preservation applications.

Decay and Termite Resistance of Wood Modified by High-Temperature Vapour-Phase Acetylation (HTVPA), a Simultaneous Acetylation and Heat Treatment Modification Process.

High-temperature vapour-phase acetylation (HTVPA) is a simultaneous acetylation and heat treatment process for wood modification. This study was the first investigation into the impact of HTVPA treatment on the resistance of wood to biological degradation. In the termite resistance test, untreated wood exhibited a mass loss (MLt) of 20.3%, while HTVPA-modified wood showed a reduced MLt of 6.6-3.2%, which decreased with an increase in weight percent gain (WPG), and the termite mortality reached 95-100%. Furthermore, after a 12-week decay resistance test against brown-rot fungi (Laetiporus sulfureus and Fomitopsis pinicola), untreated wood exhibited mass loss (MLd) values of 39.6% and 54.5%, respectively, while HTVPA-modified wood exhibited MLd values of 0.2-0.9% and -0.2-0.3%, respectively, with no significant influence from WPG. Similar results were observed in decay resistance tests against white-rot fungi (Lenzites betulina and Trametes versicolor). The results of this study demonstrated that HTVPA treatment not only effectively enhanced the decay resistance of wood but also offered superior enhancement relative to separate heat treatment or acetylation processes. In addition, all the HTVPA-modified wood specimens prepared in this study met the requirements of the CNS 6717 wood preservative standard, with an MLd of less than 3% for decay-resistant materials.

Application Lemongrass Extract (Cymbopogon citratus Dc) Against Mortality Death of Termites (Macrotermes gilvus Hagen) With Several Application Techniques

Lemongrass is a plant that contains citronellal, geraniol, and other compounds which are known to increase termite mortality. This research aims to determine the most effective concentration of lemongrass extract on termite mortality using several application techniques. The method used in this research was a Factorial Completely Randomized Design (CRD), with 3 replications where: Treatment factor I used lemongrass extract application. This treatment consists of 10 combinations and in 1 treatment unit there are 30 termites ( Macrotermes gilvus Hagen), so the total is 900 termites. The parameters observed were the percentage of termite mortality (%) and termite activity after application with 3 categories: 1=Alive actively moving; 2=Alive not actively moving; 3=Dead, so the data was analyzed using the Variety Print Analysis Method and Kruskal Wallis Analysis. Significant data analysis results will be followed by the Duncan Mean Range Test (DMRT) at ɑ=5%. The results of the study showed that the application of lemongrass extract (Cymbopogon citrates DC) 100g/l of water was significant in reducing termite (Macrotermes gilvus Hagen) mortality by up to 95% on day 7. The effectiveness of the feeding technique was not significantly different from the spraying technique in reducing actual mortality to 85.44 %. The interaction between the application of lemongrass extract (Cymbopogon citratus DC) 100g/liter of water and the application technique did not significantly reduce the mortality of termites ( Macrotermes gilvus Hagen)

Sulfuryl Fluoride Fumigation as a Quarantine Treatment for the Control of Reticulitermes speratus Kolbe (Blattodea: Rhinotermitidae) in Wood.

High-risk termites in wood imported to the Republic of Korea are currently treated with methyl bromide (MB), which has ozone-depleting properties and is highly toxic. This study evaluated the effectiveness of sulfuryl fluoride (SF) as a quarantine treatment against Reticulitermes speratus Kolbe (Blattodea: Rhinotermitidae) in wood, along with its wood sorption and penetration capacity. The LCt50 and LCt99 values for SF were 30.87 and 42.53 mg h/L at 23 °C and 151.62 and 401.9 mg h/L at 5 °C, respectively. The SF Ct values did not significantly differ between dry and wet wood at loading ratios of 10%, 30%, and 50% at both 5 °C and 23 °C (p > 0.05). In a closed wooden cube, the LCt50 and LCt99 for SF for R. speratus were 31.59 and 53.34 mg h/L, respectively, indicating an excellent wood penetration ability. SF caused 100% termite mortality with a 90% loading ratio in the scale-up trials (500 L). The SF concentration during ventilation decreased below the threshold limit value (TLV) of 5 ppm within 30 min, confirming that the working conditions were safe. This study provides a basis for the use of SF as an alternative to MB for the treatment of termites in wood.

Pemanfaatan Limbah Kayu Ulin (Eusideroxylon zwageri) sebagai Bahan Pengawet untuk Mencegah Serangan Rayap Kayu Kering pada Kayu Jabon (Anthocephalus cadamba)

Eusideroxylon zwageri wood is a type of wood wich have high natural durability that contains extractive compounds such as alkaloids, tannins, saponins, flavonoids, and phenolics that are toxic to wood-destroying organisms. The ironwood sawmill industry produces waste in the form of sawdust that has not been used but only disposed of into the environment. Therefore, that wood sawdust waste can be used as a natural wood preservative to preserve wood whish have low natural durability such as Anthocephalus cadamba. In this study, A. cadamba wood preservation was carried out with irondust extract with various solution formulas, namely 5%, 10%. 15% and 20%. The purpose of this study was to know the effect of irondust extract solution formula as a preservative on the results of jabon wood preservation which includes absorption and retention of preservatives, mortality of dry wood termites, and the percentage of weight reduction of test samples after being fed to dry wood termites. The results of this research showed that the irondust extract solution formula had a significant effect on the absorption and retention of preservatives and the mortality of dry wood termites. The 20% irondust extract solution formula resulted in a higher preservative retention and drywood termite mortality value than the 5%, 10% and 15% solution formula, which was 12.13 Kg/m3 for retention and 88% for drywood termite mortality.

Pemanfaatan Air Leri dan Air Mikroorganisme Lokal Sebagai Pengendali Rayap Tanah

Termites (Coptotermes curvignathus) are considered more dangerous than other termite species as they can cause significant damage to plantation and agricultural crops, with widespread distribution. The use of chemical pesticides to control this pest can lead to resistance and have negative impacts on the environment and human health. An environmentally friendly solution involves utilizing natural plants/substances as botanical insecticides, such as rice washing water and local microorganism (MOL) water. The aim of this research is to evaluate the effects of these two substances on termite population control and determine the optimal formulation that can act as a termite repellent. and to determine the optimal formulation as an anti-termite. The research methodology involves determining formulations of botanical insecticides, namely 100% rice washing water, 100% MOL water, 50% rice washing water : 50% MOL water, 75% rice washing water : 25% MOL water, 25% rice washing water : 75% MOL water. Each test box is filled 5 soldier termites and 20 worker termites, then provided with test papers that have been soaked in the predetermined formulation. Each treatment is repeated three times and observed every 24 hours for 72 hours. The research results indicate that all formulations uses did not have a significant impact on termite mortality. It can be concluded that the use of rice washing water and MOL water in the tested formulations is not effective as an insecticide to control termite.

Wood resistance of Magonia pubescens (Sapindaceae), Dalbergia nigra, and Machaerium amplum (Fabaceae) to Nasutitermes sp. (Blattodea: Termitidae).

Termites of the genus Nasutitermes sp. (Blattodea: Termitidae), which feed on cellulose, may cause wood to become brittle and fragile. This study aimed to evaluate the natural resistance of three native wood species: Magonia pubescens (Sapindaceae), Dalbergia nigra and Machaerium amplum (Fabaceae) to attack by Nasutitermes sp. termites and to investigate the relationship between resistance, extractive content, and oven-dry density. Samples of each wood species were subjected to a forced feeding process with Nasutitermes sp. termites for 30 days. Following the exposure, the oven-dry density, extractive content, percentage of wood loss, and termite mortality were determined for each sample. Dalbergia nigra exhibited resistance to termite attack and had the highest extractive content at 13.14%. Conversely, M. amplum had the highest wood loss at 5.37% and the lowest extractive content at 1.94%. Both species showed a negative correlation between wood loss and extractive content, but no correlation with wood density. Magonia pubescens had the highest density at 0.90 g/cm3. Macherium amplum and M. pubescens caused 100% termite mortality, while D. nigra caused 40% mortality.

Pengaruh Air Cucian Beras dan Air Mikroorganisme Lokal Terhadap Mortalitas Rayap Tanah

Subterranean termites (Coptotermes curvignathus) are dangerous termites compared to other types of termites because thay cause damage to crops in plantations and agriculture and have a wide distribution. The use of chemical pesticides causes pests to become resistant and harmful to the environment and health. Botanical pesticides are used as an alternative solution that is environmentally friendly by utilizing leri water and MOL water. This research aims to determine the effect of leri water and lokal microorganism ater (MOL) to control subterranean termites and to determine the optimal formulation as an anti-termite. The research method using 5 formulations of botanical pesticide, namely 100% leri water, 100% MOL water, 50% leri water : 50% MOL water, 75% leri water : 25% MOL water, 25% leri water : 75% MOL water and control (without formulation). Each test container contains 5 soldier termites and 20 worker termites and is given a filter paper test that has been soaked with a predeterminated formulation. Each treatment was replicated 3 times and observed every 24 hours for 72 hours. The results showed that all formulations had no effect on subterranean termite mortality.

Effect of gamal leaves (Gliricidia sepium ) extract against termite (Coptotermes curvignathus)

The World Health Organization (WHO) estimates around 3 million people working in the agricultural sector experience insecticide poisoning, and 18 thousand of them die every year. The massive use of synthetic insecticides can harm non-targeted organisms such as plants and livestock. Moreover, this may lead to ecological imbalance and increase pollution. Thus, there is a need for innovation in making natural insecticides. Indonesia is home to abundant plant diversity; one of those is the Gamal plant (Gliricidia sepium). Previous studies found that Gamal leaves contain secondary metabolites such as flavonoids, alkaloids, tannins, saponins, and steroids. Flavonoids are known to have a toxic effect on mealybugs in the papaya plant, and tannins are antimicrobial and often used as pest control. Based on this, the Gamal plant has potential as a natural insecticide. One of the most critical pests in agriculture and households is termites (Coptotermes curvignathus), which often cause losses by damaging plants and household furniture. Also, there is no research yet on Gamal leaves against termites. Therefore, research is necessary to test the effectiveness of Gamal leaf extract against termites. In this study, experimental research was used with a quantitative approach. The Gamal leaf extract was obtained using ethanol and methanol solvents through a maceration technique. Several termites were acclimatized, and 120 were taken randomly for toxicity testing. Four concentrations (10%, 25%, 50%, and 75%) were applied to each group of ten termites. This treatment was repeated three times, and the termite mortality time was measured. Afterwards, the value of LC50 was determined using a regression line between log concentration and probit mortality. The result shows that the higher the concentration, the shorter the termite death time. The mortality rate reaches 100% within 1 to 2 minutes after treatment. The LC50 value of Gamal leaves extract against termites obtained is 5,1%. This indicates that Gamal leaves are very effective in killing termites, even in the lowest concentration. It is likely caused by secondary metabolites, especially flavonoids, that have insecticidal effects. In brief, the ethanolic and methanolic extract of Gamal leaves has the potential to be a natural insecticide to substitute synthetic insecticide, which is safer, economical, and environmentally friendly.

Mechanical properties of structural particleboard and termite and decay resistance

The mechanical properties and termite and decay resistance performance of wood-based panel used in wooden houses were evaluated. The physical and mechanical properties, along with the resistance levels, of commonly used wood-based panels, including oriented strand board, structural particleboard, and particleboard for use in interior, were compared. The structural particleboard complied with the physical, mechanical, and formaldehyde emission standards of the International Organization for Standardization and Japanese Industrial Standard, surpassing the requirements for oriented strand board. The structural particleboard exhibited excellent water resistance and a consistent performance. Decay tests classified the particleboard and structural particleboard as “Resistant,” with mass losses of 7.82 to 12.72% (white rot) and 14.69 to 16.55% (brown rot). Pine (Pinus densiflora) and oriented strand board exhibited no decay resistance, with mass losses exceeding 45%. The particleboard and structural particleboard demonstrated superior termite resistance, resulting in 100% termite mortality in three days without chemical treatment. The structural particleboard exhibited excellent water, decay, and termite resistance, which can be an advantage in wooden-house construction in terms of maintenance.

Effect of teak wood on recycled HDPE/pine wood composites subjected to termite attack and accelerated weathering

This study aimed to investigate the impact of including teak wood in recycled high-density polyethylene wood plastic composites (WPC) with pine wood on their resistance to degradation caused by termite attack and accelerated weathering. A 23 factorial experimental design was conducted with three repetitions in the center to analyze the weight loss and termite mortality during the experiments. The factors studied were the days of exposure to accelerated weathering, days of exposure to termite attack, and the concentration of teak wood in the composite. Surface characterizations (SEM and FTIR) were carried out to analyze the exposed surfaces and determine the chemical modification of the composite components. The results showed that the WPC manufacturing process promotes a heterogeneous distribution of the wood particles, being greater within the center of the samples than on the surface. Specimens exposed to both accelerated weathering and termite attack resulted in a certain weight loss and termite mortality, depending on the material, conditions of exposure, and the content of teak wood in the WPC. When those compounds were subjected to accelerated weathering followed by termite attack they exhibited a higher termite attack. The presence of teak wood in the WPC produced a reduction in the effects of termite attack and accelerated weathering on weight loss and an increase in termite mortality compared to the WPC with only pine wood, as teak wood contains extractables with termiticidal action. The lowest value of weight loss (0.06%) was observed for the WPC with the highest amount of teak wood with termite attack, resulting in a termite mortality rate of 100% after 17 days of exposure.

Termite and decay resistances of Sumatran elephant dung-based particleboard modified with wood shavings and bamboo layering

Elephant dung (ED) particleboard (PB) still has subpar physical and mechanical qualities. In earlier research, adding wood shavings and bamboo layers to ED-derived PB successfully enhanced its physical and mechanical qualities. However, the resistance to termites and decay of this PB is still unknown. Therefore, this study examines the resistances to termites and decay of the PBs from ED fiber-modified with wood shavings and bamboo layering. ED and wood shavings were distributed throughout the PB in ratios of 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 (w/w %). Meanwhile, tali bamboo (Gigantochloa apus), talang bamboo (Schizostachyum brachycladum), kuning bamboo (Bambusa vulgaris), belangke bamboo (Gigantochloa pruriens), and betung bamboo (Dendrocalamus asper) were the materials used in this study. These findings demonstrated that adding wood shavings could improve PB’s resistance to termite and decay attacks. However, in this investigation, the layering of bamboo diminishes the PB’s resistance to termite and decay attack. A 50/50 ratio between ED and wood shavings achieved slightly higher termite mortality and lower weight loss than others. Meanwhile, kuning bamboo had lower termite mortality and higher weight loss than others.

Aktivitas Antirayap Ekstrak dan Fraksi Biji Jeruk Sambal (Citrus microcarpa Bunge) Terhadap Rayap Tanah (Coptotermes curvignathus Holmgren)

Citrus microcarpa is one of the Rutaceae family plants which is commonly used for food industries to enhance aroma and flavor. This plant contains secondary metabolites such as terpenoids, flavonoids, and phenolics. Unfortunately, bioactivity information, specifically anti-termites from citrus seeds is unreported. The aim of this study was to determine anti termite activity of the methanol extract and fractions of the citrus seeds against Coptotermes curvignathus Holmgren. The research was carried out in several stages, starting from maceration, partitioning, phytochemical testing, and termite activity testing for 7 days. The results of the subterranean termite mortality test were justified based on the LC50 values, from the smallest to the largest values, respectively, chloroform fraction 1.689%, methanol fraction 1.783%, n-hexane fraction 1.788%, and methanol extract 2.324%. The results of termite mortality which reached 100% for each tested sample were due to the extract and fractions of the citrus seeds have antifeedant activities.

Entomopathogenic Potential of Bacillus velezensis CE 100 for the Biological Control of Termite Damage in Wooden Architectural Buildings of Korean Cultural Heritage.

Biocontrol strategies are gaining tremendous attention in insect pest management, such as controlling termite damage, due to the growing awareness of the irreparable harm caused by the continuous use of synthetic pesticides. This study examines the proteolytic and chitinolytic activities of Bacillus velezensis CE 100 and its termiticidal effect through cuticle degradation. The proteolytic and chitinolytic activities of B. velezensis CE 100 systematically increased with cell growth to the respective peaks of 68.3 and 128.3 units/mL after seven days of inoculation, corresponding with the highest cell growth of 16 × 107 colony-forming units (CFU)/mL. The in vitro termiticidal assay showed that B. velezensis CE 100 caused a rapid and high rate of termite mortality, with a median lethal time (LT50) of >1 h and the highest mortality rates of 91.1% and 92.2% recorded at 11 h and 12 h in the bacterial broth culture and crude enzyme fraction, respectively. In addition to broken setae and deformed sockets, termites treated with the bacterial broth culture exhibited degraded epicuticles, while the crude enzyme fraction caused severe disintegration of both the epicuticle and endocuticle. These results indicate the tremendously higher potential of B. velezensis CE 100 in the biological control of subterranean termites compared to the previously used entomopathogenic bacteria.

Bioaktivitas Usnea barbata (L.) F.H. Wigg sebagai Insektisida Nabati Coptotermes curvignathus (Holmgren)

The subterranean termite Coptotermes curvignathus is a type of insect that damages wood until it is porous and destroyed. Until now, termites are chemically controlled but negatively impact the environment, so bioinsecticides such as from Usnea barbata lichen are needed. This study aims to determine the bioactivity of U extract. Barbata as a bioinsecticide for subterranean termites C. curvignathus. The experiment used Completely Randomizd Design with 7 treatments (concentrations of 0%, 5%, 10%, 15%, 20%, 25%, and Termicon) and 3 replicates. The extract was prepared from 300 g of U barbata powder, macerated in 7 days in 96% ethanol in a ratio of 1:10 (300 g/3 L). Mortality and feed weight loss were observed for 7 days. The extracts contained alkaloids, flavonoids, terpenoids, steroids, saponins, and tannins. The phytochemicals were analyzed descriptively, and a lethal concentration value of 50% (LC50) was determined by probit analysis. Data on termite mortality percentage and feed loss percentage were analyzed using ANOVA at a 5% confidence level. If the Fcalct > Ftable, Duncan's further test was carried out. The results showed that the extract contained alkaloids, steroids, tannins, and saponins. The mortality of subterranean termites was indicated by an LC value of 50-72 hours of 19.32%. Statistically, U. barbata extract affected mortality but did not differ significantly in the feed weight loss of C. curvignathus subterranean termites.
 
 Keywords: bioactivity, Coptotermes curvignathus, insecticide, Usnea barbata

Anti-Termite Activity of Azadirachta excelsa Seed Kernel and Its Isolated Compound against Coptotermes curvignathus

Azadirachta excelsa, is a plant belonging to the same genus as Indian neem (Azadirachta indica), and its use as a pesticide is reported by few studies. Despite being a different species, it is expected to have the same biopesticide potential as A. indica. Therefore, this study aims to investigate the anti-termite activity of n-hexane and methanol extracts of A. excelsa seed kernel at various concentrations against Coptotermes curvignathus. The methanol extract demonstrated greater termicidal activity than n-hexane at doses test of 2%, 4%, and 8%. It also showed 100% termite mortality on the third day of administering the 8% dose. According to the gas chromatography with mass spectrometry data, the putative main components of the n-hexane extract were hexadecanoic acid, ethyl ester (18.99%), 9,12-octadecadienoic acid (Z,Z)- (16.31%), and 9-octadecenal (16.23%). In contrast, the principal constituents of methanol extract were patchouli alcohol (28.1%), delta-guaiene (15.15%), and alpha-guaiene (11.93%). Furthermore, limonoids profiling of A. excelsa methanol extract was determined using Ultrahigh-performance liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry. The number of limonoids identified tentatively was fifteen, such as 6-deacetylnimbin, nimbolidin C, nimbolide, 6-acetylnimbandiol, 6-deacetylnimbinene, salannol, 28-deoxonimbolide, gedunin, nimbandiol, epoxyazadiradione, azadirone, 2’,3’-dihydrosalannin, marrangin, nimbocinol, and azadirachtin. They were the same as those reported in the seed and leaves of A. indica, but its largest component in A. excelsa was 6-deacetylnimbin. As a result, the presence of these compounds may be responsible for the anti-termite activity of A. excelsa seed kernel extract. Additionally, column chromatography of methanol extract yielded 6-deacetylnimbin, which was found to be antifeedant and termiticide against C. curvignathus.