Evaluation of the Efficacy of Essential Oil Extracts in the Control of Termites (Isoptera: Termitidae) in Cashew Orchards in Badikaha (Côte d’Ivoire)

Cashew tree has gradually moved from a purely ecological aspect to a socio-economic one, due to the marketing of its nuts. But production per area, estimated at between 424 and 547 kg/ha, remains low, in contrast to India (2nd largest producer) and Vietnam (3rd largest producer), whose yields range from 1000 to 1500 and 2000 to 2500 kg/ha respectively. This low yield is due to a number of factors, among which insect pests are the most damaging. Among these insects, termites are considered to be one of the main pests of cashew trees. The general objective of this study is to contribute to termite management through the use of bioinsecticides, an alternative to the use of chemicals in cashew orchards. Five (5) biological products were tested: Limocide, Carapa oil, Neem oil, Kitana and Kaskara. Among them, two products proved effective, with a mortality rate of over 50%. These were Limocide, whose LC50 was obtained in 24 h at a dose of 3.6 g/ml and 3.1 g/ml , giving a mortality rate of 57.66% ± 4.04% and 51.33 ± 2.08 respectively , and Carapa, at a dose of 4.5 g/ml, with an estimated mortality rate of 52.33% ± 1.52%. Such results have demonstrated the potential application of Limocide and Carapa biopesticides to sustainably control termites in cashew orchards of Côte d’Ivoire.

Evaluation of the virulence of entomopathogenic fungus, Isaria fumosorosea isolates against subterranean termites Coptotermes spp.(Isoptera:Rhinotermitidae)

The entomopathogenic fungus Isaria fumosorosea Wize, formerly known as Paecilomyces fumosoroseus is reported as a promising biocontrol agent for controlling subterranean termites, particularly those belonging to the family Rhinotermitidae. In Malaysia, the family Rhinotermitidae includes two species of subterranean termites with extremely high economic importance; namely Coptotermes curvignathus Holmgren, and the Asian SLubterranean Termite (Coptotermes gestroi Wasmann). To comprehend the potential control of this soil-dwelling fungus against these subterranean termites in Malaysia, an investigation was carried out by testing the pathogenecity of 11 isolates against these termite species. All isolates showed pathogenic potential against the termite (Mortality rate of C. curvignathus:84.4%; C. gestroi:67.3%). IsolatePF49 was the most effective against both species of termites and was further tested for its virulence and mycosis.The LC_(50) values of PF49 against C. curvignathus and C.gestroi were 7.55×103 and 1.09×102 conidia/ml,respectively. The average number of days required to complete the mycosis process in C. curvignathus and C.gestroi were 4.7 and 8 days, respectively. These fungi are believed useful for protecting living trees, plants, wood,wood structures, and other cellulosic materials susceptible to termite infestation and damage.

Effects of Selected Pesticidal Plants on Termites Affecting Maize Production in Arusha, Tanzania

Investigations under laboratory and field conditions were carried out with purpose of understanding the effects of pesticides of Cupressus lusitanica, Tephrosia vogelii, Eucalpytus dalrympleana, Lantana camara and Azadirachta indica in the control of termites which affect maize production in Arusha, Tanzania. Termites were collected before and during maize season of 2018 and identified at the Tropical Pesticides Research Institute (TPRI) laboratory. A total of 5279 out of 5307 termite species identified belong to genus Macrotermes, 23 species to genus Odontotermes and 5 species were unknown. The results entailed that the area is rich in species of genus Macrotermes. Moreover, concentrations i.e. 5 g, 10 g and 20 g of each botanical were tested for Macrotermes spp. mortality and repellency ability in the laboratory using a completely randomized design (CRD) with three replicates. The results showed that 98.33% Macrotermes spp. mortality was caused by T. vogelii followed by 93.33% recorded from E. dalrympleana after 24 hours. Besides, C. lusitanica repelled Macrotermes spp. by 97% followed by 95% recorded from T. vogelii and E. dalrympleana each. For field trials, 20 g of each botanical was applied using randomized complete block design (RCBD) with four replicates. The results obtained from field indicated that T. vogelii was more effective to protect maize with an average of 6 maize stands and 3.4 kg of dry total weight of maize grains next to positive control per plot. Also, average of 4 maize stands and 3 kg dry total weight of maize grains were recorded from treatments of E. dalrympleana and C. lusitanica each. Such results highlight the potential of developing bio-termiticides from T. vogelii, C. lusitanica and E. dalrympleana to control Macrotermes spp.

Analysis of Feed Preference of Edible Termites (Isoptera) on Selected Plants and Their Crude Extract Phytochemistry

Termites are social insects that inhabit colonies in the soil. Termites feed on a wide range of plants found within diverse habitats of Luanda Sub-County. This study aimed at assessing feed preference of edible termites and analyzing their phytochemical composition. Termites were exposed to ten different test plants in their natural habitats to assess feed preference. Forty-seven study sites were selected as they had high termite abundance from previous studies. The test plants were Grevillea robusta, sugarcane, maize, blue citronella grass, Eucalyptus, mango, avocado, neem, bamboo and a mixture of all the ten plants. Small pits were dug in the ground where the ten treatments were placed and replicated four times each. The test plants were placed in the evening then covered with soil block. The number of termites feeding on the test plants was counted after 12 hours the following day. There were separate trials for crushed and uncrushed feed substrates. The feed substrates that showed high feed preference was selected for phytochemical analysis. The plants whose crude extract was obtained were Grevillea robusta, bamboo, Eucalyptus, cypress, maize and sugarcane. The results for this study were analysed using one-way ANOVA. The study revealed that crushed feed substrates had a high level of feed preference by termites p < 0.05. The mixture of all the feed substrates also showed high termite preference and a mean and SE of 676.500 ± 41.7a. Phytochemical analysis of the crude plant extracts revealed that Eucalyptus had the highest number of phytochemicals present 9 out of 12. The identified phytochemicals were saponins, tannins, alkaloids, resins, cardiac glycosides, carbohydrates, phenols and flavones.

Natural Resistance of Two Plantation Woods Populus × canadensis cv. and Cunninghamia lanceolata to Decay Fungi and Termites

Natural durability of two plantation woods, Chinese fir and I-214 poplar, was investigated thoroughly by three test- ing methods, namely an accelerated laboratory decay test, a fungus cellar test and a field test. After the decay test using Postia pla- centa and Trametes versicolor, Chinese fir and the I-214 poplar showed 34% and 69% of mass loss, respectively, indicating they should be classified as slightly durable and non-durable wood. This conclusion was confirmed by the fungus cellar test and the field test. Like the performance in the decay test, I-214 poplar showed no resistance to termites either in the laboratory or in the field, whereas Chinese fir would be classified as moderately resistant.

Electrical Performance and Effect of Frequency Electromagnetic Waves on Subterranean Termites <i>Coptotermes curvignathus</i>Holmgren

The research aimed to propose a non-destructive technology to control subterranean termites Coptotermes curvignathus Holmgren infestation based on electromagnetic waves. A portable apparatus for this technology has been built and its experiment is presented in this paper. Some electrical parameters were measured and analyzed along with their effects to the termites. The experiment using frequency range between 30 Hz - 600 kHz has been done. The average error of the apparatus by comparing the result with the direct measurement using oscilloscope was also measured. The highest error value appeared at 600 kHz with frequency error 6.05 kHz. The highest error of voltage (i.e. 0.186 Volt) appeared at 100 kHz. For safetiness, the highest magnetic field at 300 kHz was 0.1815 μT and at 500 kHz was 0.00725 μT which were safe for human. The average value of termites mortality was higher on irradiation time 120 minutes than 60 minutes respectively in all test frequency: 300 kHz, 400 kHz, 500 kHz and 600 kHz. This paper presents an important information of the electromagnatic-based technology for environmental friendly termites control in spite of using the insecticides.

Assemblages and species diversity of wood destroying termites in different land use systems in Western Ghat, India

Spatial distribution, abundance and assemblage of termites depend mainly on the local conditions and habitats in which they thrive. Striking differences are observed in the species richness, number of clades and functional diversity of termite assemblage between different habitats. This study aim was to examine effect of human interference in the diversity of wood destroying termite in forest areas as well as managed and unmanaged plantations in South India. Termites attacking trees and wooden logs were collected from forest areas, managed plantations and unmanaged plantations. The termites collected were identified and compared for species abundance, richness and species diversity. Results show that the species composition and species diversity of the wood destroying termites vary according to the conditions. The species diversity measures revealed that there is a significance variation among the forest fauna and plantations. The forest areas have the highest species composition compared to plantations. Species richness is high forest areas. Even though the abundance of termites are more in unmanaged plantations, there is no significant difference related to species diversity among the managed and unmanaged plantations.

Termites Improve the Horizontal Movement of Carbonized Particles:A Step towards Sustainable Utilization of Biochar

Soil amendments containing carbonized materials increase the soil carbon reservoir,influence plant productivity,and,ultimately,help to clean the environment.There is data on the effect of such additions on soil physicochemical properties or plant growth,but few studies have focused on how these carbonized materials are distributed by termite species in the soil ecosystem.It is the first comprehensive study of the transportation of biochar(BC)by termite species under tropical environmental conditions in Pakistan.The present study was carried out to test the hypothesis that if termite species I)were involved in the distribution of biochar particles II)if yes,then how far these particles were transported during the study period(10 days)and III)check their preference between the enriched BC(EBC)and non-enriched BC.BC was enriched with the cattle slurry after its pyrolysis in the study.The results showed that EBC particles were significantly more widely distributed than non-enriched BC particles,but both types of BC were transported more than 4 cm(ring 4)within 10 days(at the end of the experiment).The current study also revealed that EBC was easily attached to the setae,cuticle,and legs of termites,implying that it could potentially be transported over a greater distance.Furthermore,transportation of EBC over larger distances indicated a potential preference of termite species between the EBC and BC particles.During the study,however,the preference among the termite species was also observed.Under the prevailing study conditions,the Coptotermes heimi and Heteroterme indicola species transported the EBC further than Microtermes obesi and Odontotermes obesus.These findings revealed that transportation preferences were observed among the four termite species.In conclusion,the current study found that termites were involved in the distribution of BC particles,with a preference for EBC and that these have the potential to transport BC particles more than 4 cm within 10 days.Furthermore,two species Coptotermes heimi and Heteroterme indicola may be more suitable candidates for EBC transpiration in Pakistani soils.It was necessary to conduct additional research into the effect of temperature on the transportation process.

Polyethism in Termites

Polyethism or division of works among workers of social insects is always a hot issue among entomologists. Honey bees, ants, and wasps are the main target for scientists to study the division of works. Studying polyethism in termites has been increased recently due to the damages to the forests, buildings, boats and even water preserving monuments. Every year a huge amount of money is spent to control these isopteran social insects in the south east of Asia, the US, Australia and other tropical and subtropical regions. As understanding the polyethism in these social insects can be a hand in controlling them, in this review we have tried to explain different kinds of polyethism and their importance in these social insects.

Morphological Identification of Edible Termites (Isoptera) in Luanda Sub-County, Kenya

Termites are social insects that live in colonies underground. Globally, there are 3000 termite species, of which 39% are found in Africa. Termites are used as food and livestock feed in most communities of the world. In Kenya, termites are consumed by many communities, especially in the western region. Termite species diversity across different parts of the Luanda sub-county was established as there are many edible and non-edible species in the area. This study assessed the species diversity of termites in Luanda sub-county, and characterized them morphologically. Termites were sampled in Luanda sub-county using the line transect method. The collected termites were preserved in tubes containing 70% Ethanol. The preserved samples were taken to the National Museums of Kenya for morphological identification up to species level. Species richness of each habitat was analyzed for diversity (Shannon-Wiener) index and Shannon index by using Vegan package version 1.16 - 32 in R. The differences in species composition and diversity of termites were analyzed using one-way ANOVA. Morphological identification recorded seven species, namely, Macrotermes herus, Macrotermes spp1, Macrotermes sp1, Pseudocanthotermes grandiceps, Macrotermes bellicosus, Macrotermes spp2 and Pseudocanthotermes militaris. The results of this study showed that the Shannon diversity index H was 0.3606 while Simpson index D was 0.20644, which implied a high species diversity of termites in Luanda sub-county a leading producer of edible termites in Kenya.

The effect of ergosterol on the allogrooming behavior of termites in response to the entomopathogenic fungus Metarhiziumanisopliae

Termites have physiological and behavioral immunities that make them highly resistant to pathogen infections,which complicates biocontrol efforts.However,the stimuli that trigger the pathogen-avoidance behaviors of termites are still unclear.Our study shows that workers of Coptotermes formosanus exposed to the conidia of Metarhizium anisopliae exhibited a significantly higher frequency and longer duration of allogrooming behaviors compared with untreated termites.Volatile compounds in the cuticle of control termites and termites previously exposed to a suspension of M.anisopliae conidia were analyzed and compared using a gas chromatography-mass spectrometer(GC-MS).Our results showed that the amount of ergosterol differed between the fungus-exposed and control termites.Choice tests showed that termites significantly preferred to stay on filter paper treated with ergosterol(0.05,0.1,or 1.0 mg/mL)compared with control filter paper.In addition,termites exposed to ergosterol followed by M.anisopliae conidia were allogroomed at a significantly higher frequency and for a longer duration than termites exposed to alcohol(the solvent used with the ergosterol in the ergosterol trials)alone followed by M.anisopliae conidia.These results showed that ergosterol may enhance the allogrooming behavior of termites in the presence of entomopathogenic fungi.

Trichoderma metabolites trigger aggregation behavior in Formosan subterranean termites (Coptotermes formosanus)

Our previous studies have shown that some Trichoderma fungi trigger aggregation behavior in Formosan subterranean termites,Coptotermes formosanus Shiraki.However,the mechanisms underlying the induction of termite aggregation by Trichoderma fungi remain unclear.Here,we found that the aqueous or acetone extract of Trichoderma asperellum Samuels,Lieckfeldt&Nirenberg and Trichoderma virens Pers.ex Fries isolated from the gut or cuticle of C.formosanus elicited significant termite aggregation in 2-choice tests.We then screened 9 Trichoderma metabolites(3-acetoxy-2-butanone,phenol,3-ethoxypropionic acid,ethyl 2,4-dioxovalerate,diglycolic acid,d-valine,styrene,3-aminopyridine,and hexyl acetoacetate)that triggered termite aggregation.Among them,phenol(1000μg/mL),3-ethoxypropionic acid(10μg/mL),ethyl 2,4-dioxovalerate(1000μg/mL),and diglycolic acid(1000μg/mL)showed the strongest activities,triggering termite aggregation throughout the 24-h period.As T.asperellum and T.virens produce different metabolites that trigger aggregation behavior in termites,the mechanisms underlying the interaction between subterranean termites and Trichoderma fungi likely vary.Future studies are needed to test whether these chemicals can attract termites and increase bait consumption.

西非Termit盆地石油地质特征及成藏主控因素

西非Termit盆地是中国石油在非洲极为重要的勘探开发区块。在充分利用钻井、分析化验和地震资料基础上,开展了Termit盆地石油地质特征和成藏主控因素研究,研究表明:①Ter-mit盆地历经前裂谷期、同裂谷期、后裂谷期三大构造演化阶段,同裂谷期发育早晚两期裂谷作用形成中生代—新生代叠置裂谷盆地,宏观具有“东西分带、南北分块”的构造结构特征,控制圈闭的形成与分布。②发育上白垩统Yogou组分布广(18000 km^(2))、厚度大(600~1400 m)、成熟度适中(Ro值为0.7%~1.3%)的海相烃源岩,配置上白垩统Yogou组顶部发育的海相三角洲、古近系Sokor1组辫状河三角洲砂体,及古近系Sokor2组区域性分布的泥岩盖层,形成了上、下两套成藏组合;③明确古近系、白垩系成藏主控因素,古近系为“下生上储”的次生油气藏,油气平面和垂向分布受生烃灶、区域盖层、油源断层和优势沉积相控制,白垩系为“自生自储”原生油藏,油气富集受区域构造活动强度和白垩系内幕构造控制。④构建了基于海相广覆式烃源岩的跨世代油气成藏模式,明确Dinga断阶带、Fana凸起和Araga地堑是古近系油气勘探的有利区带,造活动相对较弱的Moul凹陷及Dinga断阶带南部是白垩系油气勘探的有利区带。地质认识指导勘探部署,在尼日尔Termit盆地获得了重大勘探突破,累计探明石油地质储量超7亿t,为中国石油海外油气增储上产奠定了坚实的基础。

Measurement of the time required for termites to pass each other in tunnels of different curvatures

Subterranean termites construct complex tunnel networks for foraging. During travel in the tunnels, termites often encounter one another when passing in opposite directions. Such encounters are likely to affect the ＂movement efficiency,＂ which is the time required for a termite to travel a certain distance in a tunnel. In this study, we explored how individual-individual encounters affect movement efficiency in tunnels by measuring the time （v） taken by two termites to pass one another in tunnels of different curvatures. Artificial tunnels of 5 cm in length and variable widths （W） of 2, 3, or 4 mm were made. Tunnel distance （D） was 2, 3, 4, or 5 cm. When D had a higher value, curvature was lower. When W = 2, T was significantly shorter in the tunnel with D = 5 than in tunnels ofD = 2, 3, or 4, whereas v was statistically the same for D = 2, 3 and 4. When W = 3, r was shorter in the tunnel with D = 5 than for D = 3 and 4, while ~ was longer in the tunnel with D = 2 than for D = 3 and 4. When W = 4, r was longer in the tunnels with D = 2 and 3 than for D = 4 and 5. Based on these observations, 3 types of termite behavior were identified： biased walking, backward walking, and zigzag walking. We considered these results in relation to foraging efficiency.

Parentage analysis in Gabonese colonies of soil-feeding termites belonging to the Cubitermes sp. affinis subarquatus complex of species （Termitidae＂ Termitinae）

Cubitermes spp. are widely distributed soil-feeding termite species in sub- Saharan Africa which play a fundamental role in soil structure and fertility. A complex of at least four cryptic species （i.e., Cubitermes sp. affunis subarquatus complex of species） has been recently described using molecular markers. In order to investigate the breeding system of these species, five microsatellite markers were used to carry out parentage and re- latedness analyses in 15 Gabonese colonies. Monogamy was confirmed as the predominant reproductive organization in Cubitermes spp. （76% of the colonies）. Within 30% of these monogamous colonies, a high relatedness between reproductives was shown, suggesting that mating between related individuals occurs. However, Cubitermes colonies can deviate from monogamy. Indeed, parental contributions by at least two related reproductives of the same sex were revealed in four colonies and polyandry was demonstrated in two of them. Infiltration of reproductives in the colony is the most plausible explanation for such cases of polygamy in Cubitermes spp.

Preliminary Study of Chemical Elements Distribution in Petroleum Source Rocks Donga and Yogou Formations of the Termit Sedimentary Basin (Est-Niger)

XRF and EDX analyses were carried out on 18 batches of representative raw samples to determine the distribution of major chemical elements in the petroleum source rocks of Donga and Yogou formations of Termit sedimentary basin. The chemical composition of these formations is dominated by silicon (Si), aluminum (Al) and iron (Fe). This is consistent with the oxide composition, which is also dominated by silicon oxide (SiO2), aluminum oxide (Al2O3) and iron monoxide (FeO). No less important chemical elements are calcium (Ca), potassium (K), sulfur (S), titanium (Ti), magnesium (Mg), manganese (Mn) and barium (Ba), as well as some of their oxides. All these major chemical elements are carried by silicate detrital minerals associated with pyrite and goethite and/or clay minerals such as kaolinite and interstratified illite, smectite and chlorite. This trend is illustrated by the values of the Si/Al and SiO2/Al2O3 ratios.

Termites and Chinese agricultural system: applications and advances in integrated termite management and chemical control

Termites are eusocial arthropod decomposers,and improve soil fertility,crop yield,and also are used by humans for their ben efits across the world.However,some species of termites are becoming a threat to the farming community as they are directly and indirectly causing major losses to the agricultural system.It is estimated that termites cost the global economy more than 40 billion USD annually,and considerable research has been done on their management.In this review,we present the available information related to sustainable and integrated termite management practices(ITM).Furthermore,we insist that the better management of this menace can be possible through:(i)improving traditional methods to keep termites away from crops;(ii)improving agricultural practices to maintain plants with more vigor and less susceptible to termite attack;and(iii)integration of available techniques to reduce termite infestation in crops and surroundings.The application of an effective combination of traditional practices with recently developed approaches is the best option for agricultural growers.Moreover,keeping in mind the beneficial nature of this pest,more innovative efforts for its management,particularly using rapidly emerging technology(e.g.,RNA interference),are needed.

尼日尔Termit盆地油气成藏新认识与勘探方向

基于地震、钻井、铸体薄片、油样和岩样地球化学分析、生烃史模拟等资料,研究尼日尔Termit海陆相叠合盆地油气成藏特征,并探讨未来油气勘探方向。研究认为:(1)Termit盆地为早白垩世和古近纪两期裂谷叠合,东部Trakes斜坡2口钻井沉降曲线显示晚白垩世沉降速率高,分析认为是遭受海侵影响造成的高沉积速率,也可能存在一期弱裂谷发育;(2)Termit盆地沉积层序主要受控于晚白垩世海侵期旋回和古近纪湖侵期旋回控制,发育海-陆“两种源汇”沉积叠合,海侵期广覆式发育的海陆相混源型烃源岩全盆地分布,湖侵期形成的古近系Sokor 1组储集层和Sokor 2组盖层叠置其上,形成了中西非裂谷系独特的海陆相裂谷叠合盆地;(3)Termit盆地早期地温梯度低,盆地主力烃源岩上白垩统Yogou组在古近纪晚期生烃。Trakes斜坡发育上白垩统Donga组成熟烃源岩,为“双源”供烃油气成藏模式,形成Trakes斜坡油田群;(4)Termit盆地海陆相裂谷叠合成藏模式新认识和勘探实践,扩大了盆地东部有效勘探面积约2500 km2,认为在盆地东南新区带Sokor 1组、新层系Donga组和上白垩统岩性目标具备勘探潜力,可作为未来勘探和选区重点。

Termit盆地上白垩统Yogou组烃源岩埋藏史、热演化史和生烃史模拟

Yogou组烃源岩作为尼日尔Termit盆地晚白垩世重要的烃源岩层系,然而缺乏对该套地层的埋藏史、热演化史和生烃史的系统研究,制约了该地区油气成藏规律的认识。结合钻井、地震二维剖面及地球化学等资料,利用BasinMod盆地模拟软件中生烃动力学模型,恢复了Termit盆地Yogou组烃源岩热演化史,分析不同地区烃源岩的热演化特征及其与油气成藏的匹配关系,为Termit盆地下一步油气勘探提供了重要依据。研究表明,Termit盆地热流值具有明显的两段式演化特征,初始热流值较低,古近纪晚期热流值达到最大,热流值介于64.3~69.2 mW/m^(2)之间;新近纪以来,盆地热状态表现为持续冷却,现今热流值介于60.7~67.4 mW/m^(2)之间。Yogou组顶部烃源岩在55 Ma进入生烃门限(R_(o)=0.5%),达到生烃高峰(R_(o)=1.0%)的时间为35 Ma,在27.5 Ma进入高成熟演化阶段(R_(o)=1.3%)。Yogou组烃源岩存在2期生烃过程,晚白垩世末期(70~60 Ma)生烃阶段主要存在于盆地深凹陷区,古近纪(40~20 Ma)是全盆地主要的生烃阶段。盆地不同构造带对比发现,Dinga凹陷烃源岩具有成熟度更高,生烃时间更早和生烃能力更强等特征,可为Termit盆地储层提供充足油气来源。古近纪Termit盆地断裂强烈活动,促使底部烃源岩生成的油气在古近系储层中聚集成藏。研究成果为Termit盆地烃源岩生烃潜力评价提供依据,并为该盆地油气勘探提供理论指导。