Subterranean termite colony elimination can be achieved even when only a small proportion of foragers feed upon a CSI bait

Termite bait products that contain chitin synthesis inhibitors (CSIs) protect structures from subterranean termites via colony elimination. A hallmark of CSI baits is their dose-independent lethal time, as workers exposed to a CSI do not die until they initiate the molting process. Due to this mode of action and termite behaviors such as trophallaxis and cannibalism, a relatively small quantity of ingested CSI can spread throughout an entire colony before secondary repellency or avoidance behaviors occur, ultimately resulting in total colony elimination. In the field, only a portion of a subterranean termite colony actively forages upon a CSI bait at any given time, suggesting that only a relatively small proportion of workers may need to feed upon a CSI bait for a colony to be eliminated. In the present study, we used varying proportions of workers from whole four-year-old laboratory-reared Coptotermes gestroi (Wasmann) colonies (~?62,500 termites/colony on average) to determine what proportion of workers need to feed upon a CSI bait in order to achieve colony elimination. A range of 0% (control), 0.5%, 1%, 2.5%, and 5% of the total worker population of colonies was allowed to feed on a formulated 0.5% noviflumuron bait for five days before being returned to their colonies. Colony elimination was observed for all 5%-fed and four out of six 2.5%-fed colonies by 107 days after CSI exposure. Our results confirm that only a small subset of the worker population of a colony must feed upon a CSI bait to achieve subterranean termite colony elimination.

     

A novel control strategy for dry-wood termite <Emphasis Type="Italic">Incisitermes minor</Emphasis> infestation using a bait system

Three types of experiments were designed to evaluate the performance of a bait system intended to control Incisitermes minor (Hagen). In the first type of experiment, Type I, the effectiveness of the bait in a small wood specimen was evaluated. In the second type, Type II, the bait effectiveness was evaluated in a larger wood specimen. Feeding arena lumber with artificial galleries was prepared for the Type III experiment so that the response of the insects to the gel could be observed. In general, the average percentage of termites that died after being exposed to the gel formulation in all three types of experiment was more than 60%, and in the gel control the average percentage of live termites was more than 95% in Types I and III, and more than 75% in Type II. These results suggest that the gel bait system used in this study has the potential to eliminate I. minor colonies. Further investigation will be necessary to increase the reliability of the bait system as a control measure against dry-wood termites.     

Termite resistance of beech wood treated with zinc oxide and zinc borate nanocompounds*

The field of wood protection is currently changing due to the restrictions imposed by the Biocidal Products Regulation. The need for development of new wood protection technologies is therefore growing. In this work, the resistance of European beech (Fagus sylvatica L.) wood impregnated with nano-dispersions of zinc oxide (nano-ZnO) and zinc borate (nano-ZnB) against the termite Reticulitermes grassei Clement was investigated. Three different concentrations (0.5%, 1%, 2%) of the nanocompounds were tested. The effects of water leaching were also investigated. A severe effect in terms of termite workers mortality was induced by both dispersions, even at the lowest concentration. In terms of termite feeding, nano-ZnO dispersions appeared to be more efficient than nano-ZnB as they induced significant improvement at concentrations as low as 0.5%. Nano-ZnB was applied at 1% or higher concentrations in order to impart similar changes. Nano-ZnB dispersions were efficient in terms of termite resistance for a concentration at least 1%. Further increasing concentration to 2% resulted in a respective increase of wood efficacy against termites. For both tested nanocompounds, water leaching did not result in any significant increase of termite feeding.     

Evaluation of the temperature and relative humidity preferences of the western dry-wood termite <Emphasis Type="Italic">Incisitermes minor</Emphasis> (Hagen) using acoustic emission (AE) monitoring

Twenty-four different combinations of six temperatures (15°, 20°, 25°, 30°, 35°, and 40°C) and four relative humidity (RH) (60%, 70%, 80%, and 90%) conditions were used for pseudergates of the western dry-wood termite Incisitermes minor (Hagen). The feeding activities of the termites were monitored by the detection of generated acoustic emission (AE) events from feeder wood blocks in a test chamber. Temperature and RH showed independent and interactive significant effects on the feeding activity of I. minor. The optimal temperature and RH conditions for the feeding activities were 35°C and 70%, respectively, and the optimal combinations were 35°C-70% and 35°C-80% with an exceptionally higher feeding activity at the combination condition of 30°C-70%.     

黑木相思与速生桉商品用材林培育的经济效益对比分析

以国家开发银行贷款建设200 hm²黑木相思与速生桉用材林培育为例,采用动态经济分析方法进行财务净现值、内部收益率等指标及投资不确定性分析,研究两者投资经营的经济效益。结果表明,计算期（13a）内,黑木相思和速生桉用材林的内部收益率、投资利润率和资本金利润率均高于行业基准收益率（8%）,项目可行。黑木相思的财务净现值、内部收益率高于速生桉,其经济效益好,盈利能力和抗风险能力强。     

Efficacy of radio frequency treatment and its potential for control of sapstain and wood decay fungi on red oak,poplar, and southern yellow pine wood species

The effectiveness of radio frequency (RF) treatment in the control of wood decay fungi (Gloeophyllum trabeum, Ganoderma lucidum, and Irpex lacteus) and sapstain fungus (Ceratocystis fimbriata) in red oak (Quercus spp.), poplar (Populus alba), and southern yellow pine (Pinus spp.) was evaluated in the laboratory as an alternative to methyl bromide (MB) treatment. Wood samples (15.5 x 10 x 10 cm) were inoculated with fungi from a 7-day culture by dipping them to a depth of one face deep (2 cm) into inoculum and incubating them at 25°C for 14 days. Identical wood samples were left uninoculated as controls. Subsequent to incubation, the wood blocks were exposed to RF radiation in an industrial 40-kW dielectric oven at temperatures between 60° and 70°C for 2 min. The test fungi were recovered and reisolated from all of the control wood blocks but not from RF-treated wood blocks. RF treatment resulted in complete inhibition of the fungus in 98%-100% of the wood samples. Moisture content loss (≥1%) was noted after wood had been exposed to RF treatment. Moisture content may be an important factor to consider with RF treatments. RF treatment can, therefore, potentially provide an effective and rapid quarantine treatment as an alternative to MB fumigation for certain pathogen-wood combinations. This article reports the results of research only. Mention of a product does not constitute an endorsement or recommendation by USDA for its use.     

Seasonal and height-dependent fluctuation of starch and free glucose contents in moso bamboo (Phyllostachys pubescens) and its relation to attack by termites and decay fungi

The potential of termite (Coptotermes formosanus Shiraki) and fungal attacks [Fomitopsis palustris (Berkeley et Curtis) Murrill (FFPRI 0507) and Trametes versicolor (L. ex Fr.) Quel (FFPRI 1030)] against moso bamboo (Phyllostachys pubescens Mazel) were evaluated with regard to the seasonal and height-dependent changes of the free glucose and starch contents, which were measured by a newly developed method. The free glucose contents were generally lower in autumn and winter than in spring and summer, whereas the lowest starch contents were obtained in August, and the contents increased almost linearly up to February and March. In terms of the height-dependent fluctuation, the free glucose contents tended to decrease as the sampling heights increased. There was no special correlation between the free glucose or starch contents and the consumption by termites, even though higher mortalities were obtained in the bamboo-fed termites than in the wood-fed termites. However, a positive correlation between the free glucose contents and mass losses of the samples at 4-m and 8-m heights from the bottom by the decay fungi was observed. For starch, no influence on fungal attack was found.     

气候谈判、木材产品国际贸易及其关系研究现状

文中介绍气候谈判产生的背景、谈判机制设计、影响谈判进程的因素等方面研究现状, 分析贸易政策与环境、资源禀赋、汇率变动等对木材产品国际贸易的影响; 在此基础上, 讨论气候谈判与木材产品国际贸易之间的关系。现有研究文献表明:气候谈判通过关税直接对木材产品国际贸易产生影响, 通过非关税措施包括森林认证、进口产品检验检疫、森林碳汇等对全球木材产品国际贸易产生直接或间接影响。然而, 这些研究主要还是基于简单的逻辑推理, 对于涉林气候谈判影响木材产品国际贸易的机理并没有进行深入剖析, 更没有通过大样本实证检验涉林气候谈判对木材产品国际贸易的影响。     

Evaluation of the concentrations of hydrogen and methane emitted by termite using a semiconductor gas sensor

A gas detection apparatus equipped with a semiconductor gas sensor was employed for qualitative and quantitative measurement of hydrogen and methane emitted by termites. A gas sample of 2.5 ml was injected into the semiconductor gas sensor through the gas detection apparatus, and the maximum voltage of the sensor was converted into gas concentration. The gas samples were collected from three distinct experiments: (1) five combinations of workers and soldiers of Coptotermes formosanus with and without a wood specimen; (2) C. formosanus under six temperature conditions; and (3) four different termite species, C. formosanus, Reticulitermes speratus, Incisitermes minor, and Zootermopsis nevadensis. The hydrogen and methane concentrations increased with an increase in the number of termites. Concentrations were higher in samples with a wood specimen than without it. Both hydrogen and methane concentrations were the highest for the samples at 35 °C and were lowest at 15 and 5 °C. The concentrations were very low at 45 °C because all the termites had died in a few hours. The concentrations of hydrogen and methane were highest for Z. nevadensis, the dampwood termite, among the four species, and no methane was detected for I. minor, the drywood termite, at 28 °C and 75 % RH.     

Leptoglossus occidentalis and Diplodia pinea: a new insect‐fungus association in Mediterranean forests

Leptoglossus occidentalis, an insect native to North America, was inadvertently introduced into Italy about 1999. The insect damages the cones of conifer trees, especially Pinus pinea (Italian Stone pine). Pinus pinea is also affected by Diplodia pinea, a fungus native to Italy, which is becoming an increasing threat because pine trees are becoming more susceptible to it as a consequence of global warming. Because the insect and the fungus both have the pine cones as a common habitat, a possible interaction between them has been postulated. The aim of this study was to ascertain whether L. occidentalis and D. pinea interact on P. pinea cones. The interaction was studied using real‐time PCR on a group of naturally infected insects collected from a forest, and a group raised in the laboratory and artificially inoculated with D. pinea conidia. Molecular analysis showed that D. pinea DNA occurred on both naturally infected and inoculated insects, but with significant differences between the two groups. The rapid and sensitive molecular technique made it possible to detect D. pinea DNA on the bodies of the insects, and to show that the native D. pinea occurred on the exotic insect.     

Vertebrate and insect pests and hemi-parasitic plants of Parkia biglobosa and Vitellaria paradoxa in Nigeria

This study investigated the occurrence and diversity of hemi-parasitic plants, vertebrate and insect pest species of Parkia biglobosa (Keay), and Vitellaria paradoxa (Gaertn.) as well as the strategies for their control in the parklands of the Nigerian humid savanna. Results indicated that of the two major hemi-parasitic plants encountered, Tapinanthus globiferus was the more widespread with wider host range than T. dodonifolius. Mechanical control by cutback of infested branches was ineffective for both species. The major vertebrate pests consist of 6 avian species from 3 families: Nectaridae, Plocidae and Cuculidae; a fruit bat, Epomops frangueti and an unidentified squirrel. The species fed on both the fruits of the trees and the seeds of the hemi-parasitic plants. Twenty insect species from 14 families were encountered on P. biglobosa compared to 33 species from 17 families on V. paradoxa in all the ecological zones covered in the study. Species diversity was comparatively higher in the fallow than in the cultivated land. The majority of the insects encountered was of little significance and may not warrant application of control. Cirina forda (Saturnidae:lepidoptera) was a major pest causing 60%–90% defoliation of mature trees of V. paradoxa. All larval stages were destructive but control at this stage is not advised because it provides incidental source of food to locals. Control after pupation using a slow-release insecticide with a soil penetration depth of 15–20 cm is suggested.This revised version was published online in November 2005 with corrections to the Cover Date.     

化学处理法对竹材阻燃、抗菌和防腐的影响(英文)

研究了6种用于印度勒竹防护的制剂,主要用于阻燃、防火防腐、抗真菌和白蚁的腐蚀。考察了阻燃剂和新型环保防腐剂ZiBOC用于印度勒竹防护的协同作用。将裂开的竹片用质量分数为15%的6种防护组分处理,即按照印度标准方法测试火焰穿透性、可燃性和燃烧率。6种15%质量分数的组分分别为:1.硫酸铵+磷酸铵+ZiBOC;2.硫酸铵+ZiBOC;3.磷酸铵+ZiBOC;4.磷酸镁+焦硫酸镁+ZiBOC;5.磷酸镁+ZiBOC;6.焦磷酸镁+ZiBOC。结果表明,达到防护目的的不同化学组分的防护剂用量应为9～11.5kg/m3。用白腐菌的腐烂实验表明,配方为2、3、5和6的防护剂表现出较好的防腐作用(防护率达到95%,p0.05),而用褐腐菌其防护率约为43%～67%。采用经2～6配方处理过的样品均能抗第一、二期的白腐腐蚀,而第二期的白蚁对配方4处理过的样品有轻微的腐蚀作用。少数几种配方对材料的耐火性有提高。     

广西国有高峰林场昆虫多样性调查研究

通过选择代表性样地,对广西高峰林场某分场部分用材林和经济林进行了昆虫多样性调查研究。结果表明:1.桉树纯林调查得到的昆虫种类有13种,昆虫多样性指数为2.114 96,处于亚稳定状态;2.马尾松纯林共调查得到的物种有19种,昆虫多样性指数为2.112 21,处于亚稳定状态;3.八角纯林共调查得到的物种有69种,昆虫多样性指数最大为3.258 12,处于稳定状态。     

云南省大围山地区病毒接种感染褐顶毒蛾试验初报

经过2 a用3种病毒野外接种褐顶毒蛾Lymantria apicebrunnea幼虫试验,表明不同病毒接种褐顶毒蛾的感病死亡率差异极显著,文山松毛虫CPV对褐顶毒蛾效果较好,20 d野外接种感染死亡率为78%;云南松毛虫NPV次之,20 d野外接种感染死亡率为56.5%;从美国引进的舞毒蛾NPV对褐顶毒蛾没有明显作用。经室内检测,接种CPV和NPV的褐顶毒蛾感病死虫单虫病毒多角体含量较高,分别为1.77亿PIB/头和0.97亿PIB/头;褐顶毒蛾感染松毛虫CPV和松毛虫NPV死亡虫pH值分别为7.556和7.554。     

绍兴市古树名木白蚁危害现状及防治对策

通过对绍兴市6县(市、区)古树名木白蚁危害情况的调查,查明危害古树名木的白蚁3科6种,其中黑翅土白蚁和黄翅大白蚁是优势种;古树名木受害率达25.1%以上;分析了易受白蚁危害的树种及古树名木受白蚁严重危害的原因;提出了相应的防治措施。     

Changes of decay and termite durabilities of Japanese larch (Larix leptolepis) wood due to high-temperature kiln drying processes

We investigated the effects of high-temperature drying schedules (120°–130°C) on decay and termite feeding of Japanese larch timbers. Thermogravimetric analysis was conducted to investigate changes of the wood components. Decay and termite feeding tests showed that specimens dried under high-temperature schedules were susceptible against a decaying fungus Fomitopsis palustris and attacks from termites Coptotermes formosanus and Reticulitermes speratus. These drying schedules changed chemical components, which were suggested by the thermal analytical result compared to the control sample. The results of this study indicated that the acceleration of termite feeding takes place even under temperatures that are comparatively lower than that used in our previous research in which 170°C steaming treatment was applied to Japanese larch wood. Decay durability against a brown rot fungus also decreased, possibly from production of low molecular weight fragments when hemicellulose decreased during the high-temperature drying processes.     

Viruses of Heterobasidion parviporum persist within their fungal host during passage through the alimentary tract of Hylobius abietis

Heterobasidion annosum (Fr.) Bref. sensu lato is an important fungal parasite of coniferous trees throughout the temperate regions of the world. Approximately 15% of Heterobasidion isolates are infected by dsRNA viruses, which are considered as obligately intracellular and transmit vertically into both basidiospores and asexual conidia. Insects such as H. abietis and its larvae feeding on wood colonized by Heterobasidion fungi may carry Heterobasidion conidia and hyphae. In this study, we used H. abietis as a model species to reveal whether Heterobasidion viruses resist in their fungal host passing through the digestive tract of insects that may potentially serve as disseminators of fungal propagules. Pinus sylvestris branches were inoculated by three different strains of Heterobasidion parviporum, hosting taxonomically diverse virus species: Heterobasidion RNA virus 2, HetRV4 and HetRV6. Then, the inoculated branches were fed to H. abietis insects, and beetle excrements were investigated for Heterobasidion infections. All the inoculated fungal strains survived passage through the alimentary tract of the insects (survival rate 25–80%). The passage rates of the viruses inside their hosts varied considerably, ranging from 0 to 67%. Two different mycoviruses, HetRV2 and HetRV6, survived the intestinal passage of their fungal host, while the virus species HetRV4 was detected among none of the five H. parviporum isolates retrieved from insect faeces. The relative stability of fungi harbouring viruses suggests that if viruses are to be used for biological control against Heterobasidion species, it is likely that insect feeding does not considerably decrease the virus effect, but might instead enhance short‐range dispersal of the viral biocontrol agent.     

应用聚集信息素监测与防治纵坑切梢小蠹

监测和防治试验结果表明：最好的诱芯9诱集效果是对照诱集效果的7706．8倍，是饵木的20．49倍；效果中等的诱芯1的诱集量是对照的4288．4倍，是饵木的11．4倍；效果最差的诱芯5诱集量为对照的830倍，是饵木的2．19倍。这一结果肯定了聚集信息素诱虫灵敏度高、效果好的特性。同时虫口密度、有虫株率和梢被害率3项指标的减退率证实了应用聚集信息素防治纵坑切梢小蠹的效果显著可靠。其虫口密度减退率平均为94．35％，有虫株率减退率平均为87．7％，被害梢减退率为88．39％。     

Enhancement of the biological resistance of wood by phenylboronic acid treatment

Phenylboronic acid (PBA) was tested in terms of boron leachability from treated wood. In addition, the fungal and termiticidal efficacy of PBA-impregnated sugi (Cryptomeria japonica D. Don) wood was tested against the decay fungi Coriolus versicolor (L. ex Fr.) Quel. and Tyromyces palustris (Berk. et Curt) Murr., representing white-rot and brown-rot fungi, respectively, and the Formosan subterranean termite Coptotermes formosanus Shiraki. Ion chromatography analysis of hot water extracts of treated wood before and after leaching indicated that PBA is considerably resistant to water leaching, and saturation of the treatment solution increased the fixation ratio of boron in wood, whereas boric acid could not remain in wood impregnated even with the saturated solution. Decay test results revealed the excellent bioactive performance of PBA. Wood treated with 0.34% PBA solution was found resistant to both decay fungi, even after running-water leaching for 10 days and treatment with 1.00% PBA completely inactivated the Formosan subterranean termite for the leached specimens. Weight gain levels were 0.18% w/w (0.46kg/m³) and 0.99% w/w (2.49kg/m³) for these concentration levels, respectively, after being leached by running water. Contrary to the general belief that boron is a slow-acting toxicant against termites and unable to prevent mass loss of treated wood, PBA acted rapidly, and the mass loss caused by termites was low.This study was presented in part at the 47th annual meeting of the Japan Wood Research Society, Kochi, April, 1997     

An evaluation of the small-scale sawmilling and timber processing industry in northern Vietnam and the need for planting particular indigenous species

This paper reports findings of surveys into small-scale sawmilling and timber processing in Phu Tho Province and the Tam Dao National Park buffer zone in northern Vietnam. The objective of these surveys was to examine the extent to which small sawmills and timber processors utilise farm-grown timber, so as to explore the prospects for expansion of farm-grown timber markets. The operational scope, supply chain and value chain of the industry are reported. Resource availability and current and future perspectives are discussed. Timber prices were found to vary greatly between species and study areas. Species most in demand by enterprises are Artocarpus heterophyllus, Melia azedarach, Manglietia conifera, Acacia spp., Chukrasia tabularis and Erythrophloeum fordii. Small-scale sawmilling and timber processing activities fit well with rural communities in Vietnam and have potential for further development if current constraints can be overcome. Further tree planting is needed to meet the presently unsatisfied timber demand and to create income and employment. Information from sawmillers and timber processors suggests the types of species that farmers should be considering for their plantings.