Fitness traits of insecticide resistant and susceptible strains of tea mosquito bug Helopeltis theivora Waterhouse (Heteroptera: Miridae)

We compared the biological traits of insecticide resistant and susceptible field populations of tea mosquito bug Helopeltis theivora Waterhouse. The insecticide resistant population of the conventional Tea Estate “Chuapara” of the Dooars, Jalpaiguri, differed significantly from the susceptible strain of the organic Tea Estate “Makibari” of Darjeeling. Both these tea plantation areas are located in the northern part of West Bengal, India. Adverse changes in biological and developmental traits were observed mainly in: (i) reduction in oviposition period; (ii) fecundity; and (iii) prolongation of nymphal and total developmental period. However, all other parameters such as pre- and post oviposition periods, egg incubation period, hatchability and adult longevity were not significantly different. These results clearly demonstrated that only certain fitness components in the resistant strains appear to be adaptively changed and lowered.     

Role of host switching in the development of pesticide tolerance in Helopeltis theivora (Hemiptera: Miridae), the major pest of tea in India

The polyphagous pest Helopeltis theivora Waterhouse (Heteroptera: Miridae) is one of the major pests of tea [Camellia sinensis, (Theaceae)]. Duranta repens (Verbenaceae), an ornamental plant producing various allelochemicals, is used in many tea estates as hedge plant. This plant was earlier reported to be an alternative host of H. theivora. To gain an insight into the pest and host–plant relationships, the present work reports studies on host-based life-cycle traits, pesticide tolerance status and levels of detoxification enzymes, such as general esterases (GEs), glutathione S-transferases (GSTs) and cytochrome P450 (CYP450). Host switching in the development of pesticide tolerance in H. theivora was evident. While comparing the biology of this pest on the primary host (tea) and the alternative host (D. repens) it was found that total developmental period was higher in the Duranta-reared population, along with significantly higher nymphal mortality and significantly less fecundity. However, there was no significant difference in incubation period, hatchability, sex ratio, pre-oviposition period and adult longevity. Susceptibility of the Duranta-reared population against quinalphos (a commonly used insecticide) was 1.41 times less than the tea-reared H. theivora population. The host-based variation in the relative susceptibility against insecticide was corroborated by differential activity of the three major xenobiotic detoxifying enzymes mentioned above. GE, GST and CYP450 activities were 2.67-fold, 1.43-fold and 1.37-fold higher in the Duranta-reared population than in the tea-reared population, possibly signifying that host switching can play a role in the development of tolerance of H. theivora against insecticides.     

A novel bacterial pathogen (Enterobacter sp.) isolated from the leaf roller, Caloptilia theivora of tea of Darjeeling foothills

Enterobacter sp. was isolated from the diseased and dead caterpillars of the tea leaf roller (Caloptilia theivora) from the Darjeeling foothill region. When the vegetative form of the bacterium was applied via food, mortality of C. theivora showed an LC₅₀ value at 363.1 μg/ml (bacterial wt./vol. of water) with fiducial limits 363.25 and 362.94 μg/ml respectively. The LT₅₀ values for C. theivora were 6 days for 100 μg/ml, 5.96 days for 300 μg/ml, 5.81 days for 500 μg/ml, 4.96 days for 750 μg/ml and 4.61 days for 1,000 μg/ml concentrations. The finding would enable one to contemplate development of a microbial pesticide using this novel Enterobacter sp. DD01 for control of the leaf rolling pest.     

陕西省栎黄枯叶蛾蛹的空间分布

栎黄枯叶蛾(Trabala vishnou gigantina Yang)是近年来在陕西吴起沙棘林中大面积暴发的一种食叶害虫,为了解其种群空间结构,有效控制危害,利用地统计学等方法,对不同坡向和疏密度沙棘纯林中的栎黄枯叶蛾蛹的空间分布进行了研究。结果表明:栎黄枯叶蛾化蛹的高峰期为8月中旬,雄性幼虫较雌性幼虫平均早3.7 d化蛹;蛹在阴坡的东南向和阳坡的西、北两方向分布比例最大;在距沙棘树基部30.00—75.00 cm范围处分布密集。由全方向的变异函数曲线分析得知:阴坡密林、阴坡疏林、阳坡密林、阳坡疏林中,栎黄枯叶蛾蛹的空间依赖范围分别为95.609、47.379、79.238、42.415 m,空间变异值分别为0.760、0.561、0.649、0.407;且在阴阳两坡向的密林中均呈聚集分布,疏林中均呈随机分布。用Kriging插值方法生成的空间分布图显示蛹在空间分布上存在一定的边缘效应,且方向性较明显。     

Variation in Esterase Activity Among Different <Emphasis Type="Italic">Aedes aegypti</Emphasis> L. Populations from the Dooars and Terai Regions of West Bengal,India

Mosquitoes are responsible for transmitting the most important vector-borne diseases like malaria, dengue etc. across the world, especially in tropical countries. The most prominent species of the genus Aedes, A. aegypti and A. albopictus act as vectors for numerous viral infections. Because of non-availability of vaccine for dengue fever, vector control stands the only approach to prevent the viral transmission. As per recommendations by World Health Organization (2015), the main insecticides used for mosquito control are DDT, malathion, chlorpyrifos, temephos, bendiocarb and synthetic pyrethroids. Excessive and unwanted usage of insecticides not only increases vectors’ resistance to insecticides, but also results in cross resistance to other insecticides. In mosquitoes, metabolic detoxifications of insecticides by detoxifying enzymes are the main strategy to withstand recurrent exposure to synthetic insecticides. Esterases are one of the three gene families of detoxification enzymes involved in metabolic detoxification of insecticide and confers resistance for organophosphorus insecticide (OP) as well as for carbamate insecticide. In the present study, the activity of α- and β-esterases have been evaluated in different A. aegypti populations collected from the Dooars and Terai regions of West Bengal, India. The activity of α-esterases was 1.2–3.1 fold and β-esterases was 2.0–23.0 fold higher than laboratory control population. The electro-phoregrams of α-esterases showed expression of 11 isozymes from two gene loci and for β-esterases showed expression of 09 isozymes from two gene loci in all the field populations of A. aegypti. The results showed a significant variation of esterase activity and isozyme expression among different population indicating variability in biochemical susceptibility among the populations. The present work presents first hand data on biochemical resistance of A. aegypti in this region and may be used as an integral component for planning and evaluation of vector-borne diseases and integrated vector management programmes.     

The role of native vegetation on infection rates of Calacarus heveae (Acari: Eriophyidae) by Hirsutella thompsonii (Ascomycota: Ophiocordycipitaceae)

Hirsutella thompsonii (Fischer) (Ascomycota: Ophiocordycipitaceae), a fungal pathogen, often causes high mortality in populations of Calacarus heveae Feres (Acari: Eriophyidae), an important pest mite in rubber tree plantations (Hevea brasiliensis Muell. Arg., Euphorbiaceae). However, the ecological and climatic factors regulating this host-pathogen system are poorly known. We compared fungal infections in agroforestry and traditional rubber plantations to evaluate the role of native vegetation and climatic factors on infection rates of C. heveae by H. thompsonii. While the prevalence of H. thompsonii was higher in managed rubber tree plantations, the abundance of C. heveae was about three times higher in traditional plantations. Abundance of C. heveae, agroecosystem management type and microclimatic variables were responsible for driving the infection rates of H. thompsonii. Native vegetation was a source for H. thompsonii and also modified the crop’s microclimate, which contributed to its maintenance in the crop fields. Therefore, appropriate management practices may enhance the effects of entomopathogens on conservative biological control of pest mites in agroforestry systems.     

Genetic Characterization of <Emphasis Type="Italic">Barilius barna</Emphasis> (Hamilton, 1822) in the Teesta River of Sub-Himalayan West Bengal,India, Through RAPD and ISSR Fingerprinting

Genetic characterization of Barilius barna, an economically important freshwater fish in the Indian scenario, is unexplored in the sub-Himalayan Dooars region of West Bengal, India. This study is the first attempt to characterize the genetic architecture of Barilius barna from the Teesta river of this region. We have studied loci polymorphism, genetic diversity, Shannon’s information index and the measure of evenness in the two populations of this river through ten RAPD and seven ISSR primer-based PCR amplifications. The result showed 89.52 and 82.21% polymorphisms in RAPD and ISSR amplification respectively. The Nei’s genetic diversity and Shannon’s information index varied from 0.172 ± 0.189SD to 0.293 ± 0.164SD and 0.265 ± 0.268SD to 0.445 ± 0.220SD respectively, which indicated low level of genetic variation. AMOVA revealed significant level of variance within the population and gene flow between the populations. Low levels of genetic variation and moderate to high levels of genetic relatedness were found in the studied populations. Expectedly, the populations were genetically not very distant from each other, as evident from the Nei’s unbiased measure of genetic distance and identity. As the species is commercially important and the region is located in the sub-Himalayan region, the management and proper rehabilitation of this ichthyofauna in the wild is urgently required. Our results may serve as a guideline for adopting such management decisions.     

福安三种不同茶园节肢动物群落的消长动态调查

根据对福建福安的3种不同茶园（天香有机茶园、北门高山茶园和溪柄平地茶园）的节肢动物群落消长动态调查。并经多样性分析,结果获知：福安3种茶园节肢动物群落的物种丰富度（s）和多样性指数（H）的大小顺序依次为：天香（S=19．64,H=2．537）〉北门（S=18．01,H=2．502）〉溪柄（S=17．59,H=2．297）;而均匀度指数的大小顺序是：北门（J=0．621）〉天香（J=0．595）〉溪柄（J=0．559）。表明植被比较丰富、人为干扰较少的茶园,节肢动物群落的物种丰富度、多样性指数和均匀度指数较高,害、益虫群落易于保持较好的平衡状态,有利于减少（或不使用）化学农药、发展绿色无公害茶叶生产。     

Monitoring <i>Thosea sinensis</i> Walker in Tea Plantations Based on UAV Multi-Spectral Image

Thosea sinensis Walker (TSW) rapidly spreads and severely damages the tea plants. Therefore, finding a reliable operational method for identifying the TSW-damaged areas via remote sensing has been a focus of a research community. Such methods also enable us to calculate the precise application of pesticides and prevent the subsequent spread of the pests. In this work, based on the unmanned aerial vehicle (UAV) platform, five band images of multispectral red-edge camera were obtained and used for monitoring the TSW in tea plantations. By combining the minimum redundancy maximum relevance (mRMR) with the selected spectral features, a comprehensive spectral selection strategy was proposed. Then, based on the selected spectral features, three classic machine learning algorithms, including random forest (RF), support vector machine (SVM), and k-nearest neighbors (KNN) were used to construct the pest monitoring model and were evaluated and compared. The results showed that the strategy proposed in this work obtained ideal monitoring accuracy by only using the combination of a few optimized features (2 or 4). In order to differentiate the healthy and TSW-damaged areas (2-class model), the monitoring accuracies of all the three models were computed, which were above 96%. The RF model used the least number of features, including only SAVI and Band_red. In order to further discriminate the pest incidence levels (3-class model), the monitoring accuracies of all the three models were computed, which were above 80%, among which the RF algorithm based on SAVI, Band_red, VARI_green, and Band_{red_edge} features achieve the highest accuracy (OAA of 87%, and Kappa of 0.79). Considering the computational cost and model accuracy, this work recommends the RF model based on a few optimal feature combinations to monitor and distinguish the severity of TSW in tea plantations. According to the UAV remote sensing mapping results, the TSW infestation exhibited an aggregated distribution pattern. The spatial information of occurrence and severity can offer effective guidance for precise control of the pest. In addition, the relevant methods provide a reference for monitoring other leaf-eating pests, effectively improving the management level of plant protection in tea plantations, and guaranting the yield and quality of tea plantations.     

茶园间作不同绿肥对节肢动物群落结构和多样性的影响

【目的】研究在茶园中合理间作绿肥对茶园节肢动物群落结构和多样性的影响。【方法】本文在茶园中分别设间作铺地木兰+罗顿豆、圆叶决明+白三叶、白三叶+平托花生3种不同绿肥组合处理,并设不间作绿肥、常规除草的茶园为对照。【结果】间作不同绿肥均能提高茶园节肢动物群落的物种丰富度和群落多样性,提高茶园捕食性天敌昆虫、蜘蛛和寄生性天敌在茶园冠层群落的比率;不同处理茶园冠层节肢动物Shannon-wiener多样性指数(H)、Simpson指数(D)和均匀度指数变化趋势基本一致;茶冠层的节肢动物群落多样性指数在4类不同处理茶园间差异显著;间作绿肥增加了茶园的生物多样性,4类不同处理茶园茶冠层群落相似性系数在0.741~0.892之间,表明4类不同处理茶园冠层群落在物种组成上有较高的相似性。4类不同处理茶园害虫与天敌两类群功能团的丰盛度之间成显著的正相关,表明天敌对害虫的空间数量跟随效应强,主要表现为二者数量间的相互作用。灰色关联度分析表明在4类不同处理茶园中的群落节肢动物物种数/个体数、天敌物种数/害虫物种数、害虫丰富度与多样性指数和均匀度指数的关联系数较高,反应了群落的多样性和稳定性。【结论】间作增强了茶园群落的生物多样性,提高害虫天敌的种类和个体数,有利有效发挥天敌对有害生物的生态控制。     

Microevolutionary changes in populations of Chironomus nuditarsis Str. (Keyl, 1962) (Chironomidae, Diptera) from central caucasus

Karyotype of the Chironomus nuditarsis Str. (Keyl, 1962) chironomids from central Caucasian populations located at different altitudes above the sea level (a.s.l.) was examined. Specific features of the inversion polymorphism of the high-mountain (more than 1000 m a.s.l.), foothill (500–1000 m a.s.l.), and plain (up to 500 m a.s.l.) populations were identified. A new chromosome banding sequence, ndt F2 (1g-e 7a–8c), which was endemic to Caucasian populations, was described. With the increase in the altitude of the reservoir a.s.l., the decrease in the frequency of ndt G1.2 and ndt B2.2 inversions and the number of inversions per individual and per arm was observed. In the high-mountain population, only the ndt G2.2 homozygotes were detected. The plain population is an interstitial population, while foothill and high-mountain populations are terminal. Cytogenetic distances between the high-mountain and other samples range from 0.174 to 0.223, which is higher than the mean interpopulation value for this species (0.138). The allochrony of the life cycle in aborigines larvae from the foothill population and aborigines from the high-mountain population can be caused by factors such as low high-mountain reservoir temperature. This factor increases the duration of the stages of larvae developmental, which leads to a reduced number of generations and results in a shift in the imago flight and mating timing.     

Modeling population dynamics of a tea pest with temperature-dependent development: predicting emergence timing and potential damage

The tea leaf roller, Caloptilia theivora Walsingham (Lepidoptera: Gracillariinae), is one of the serious pests of tea plants in Japan. To understand the mechanism of seasonal occurrence of this insect pest, we developed a population dynamics model that explicitly incorporates the temperature-dependent development of the pest. The model predictions were compared with observed captures in pheromone traps at the experimental site of the Kagoshima Tea Experiment Research Station in Japan. The results showed that the emergence timing of the insect pest observed in the field was determined primarily by temperature. The relationship between the timing of adult emergence and the leaf damage level was also studied using a logistic regression model. The infestation level decreased as the interval between the adult peak emergence date and the date of tea plucking increased, implying that asynchrony between plant phenology and emergence of the insect pest is a critical factor reducing damage level. We examined how the damage level changes according to global warming. Increased temperature made the timing of insect appearance forward and enhance asynchrony of plant–pest phenology. Therefore, reduction of damage level by the insect pest is expected under global warming.     

Avian pest control in tea plantations of sub-Himalayan plains of Northeast India: Mixed-species foraging flock matters

This study reports on the biocontrol role birds play in caterpillar pest control of tea plantations of Northeast India. In this area large tracts of tea plantations have been extensively defoliated by the recent invasion of two forest-dwelling geometrid looper caterpillars, Hyposidra spp. and a lymantriid hairy caterpillar, Arctornis submarginata. This exacerbated tea herbivory by two resident pest caterpillars, Biston suppressaria and Eterusia magnifera. Currently there are no identified resident insect predators for any life stage of Hyposidra spp. and A. submarginata. Larvae of these pests drop from tea bushes using salivary thread, allowing caterpillars to escape from insect predators. The study identified 38 native insectivorous bird species in tea plantations, of which four species (Asian-pied starling, Chestnut-tailed starling, Jungle Myna, Red-vented Bulbul) could be potential control agents of looper and hairy caterpillar pests. These species had high population densities. Their cumulative abundances represented a major proportion of the total bird community during both the infested (86.44%) and non-infested phase (75.34%). They foraged in mixed-species flocks in both tea foliage and on the ground. This behavior is suited to capture foliage-living and dropped caterpillars that were flushed from tea bushes by foraging birds. Abundance and species richness of overall tea layer-foraging birds were higher in infested phase when compared to non-infested phase. The predation rate of four bird species of the foraging flock varied significantly. These results suggest that birds should be considered as important biological control agent of caterpillar pests of tea and considered in pest management plans.     

江西省茶园土壤肥力特征及其影响因子

为探明江西省典型茶园土壤养分状况和肥力特征,选取江西省21个地区372个典型茶园,分析茶园土壤养分的差异性、空间性、相关性及与地形、土壤类型、海拔和建园时间的关联性。结果表明: 江西省茶园土壤pH、有机质、碱解氮、速效磷、速效钾、全氮、全磷和全钾分别达到优质高效高产茶园土壤营养指标的53.9%、60.1%、56.1%、22.9%、38.5%、43.7%、11.1%和95.5%,其中速效磷为强变异;有效铜、锌、铁、锰和硼达到土壤微量元素含量分级一级标准的占比分别为76.3%、74.2%、96.8%、73.1%和0.0%。江西茶园土壤养分以赣中地区最高,其次是赣东北和赣西北地区,赣南地区最低。除全钾外,土壤pH与有机质、碱解氮、速效磷、速效钾、全氮和全磷均呈显著正相关。不同地形土壤养分以平地最高,高山次之,山地和丘陵最低;不同土壤类型土壤养分以水稻土、砂壤和山地黄棕壤较高,其次是黄壤、红黄壤和紫色土,红壤最低;土壤pH、有机质和全钾随海拔上升而递增,而速效磷随海拔上升而递减;土壤有机质、碱解氮、全氮、速效磷和全磷随建园时间的增加而递增,而土壤pH随建园时间的增加而递减。综上,江西省茶园土壤肥力总体水平良好,有机质、全钾、有效铜、锌、铁和锰均较丰富,但土壤偏酸,速效磷和全磷偏低,有效硼严重缺乏。赣中应提高土壤pH和钾肥,赣东北增加钾和氮肥,赣西北增加有机质和磷肥,赣南应增加氮磷钾肥并配施有机肥;高山茶园补充速效磷和钾肥,山地茶园提高氮和磷肥;红黄壤茶园提高土壤pH和全钾,红壤茶园应提高氮磷钾肥并配施有机肥,黄壤和山地黄棕壤茶园需要增施磷肥,紫色土茶园需提高土壤有机质;茶园需要逐年增加白云石粉、生理碱性肥料和有机肥等,防治茶园土壤酸化。     

湖南省茶树害虫地理区划分析

通过湖南省茶树害虫的系统调查,查明湖南省茶树害虫(害螨)共302种,根据其在湖南省各地(市)的分布,编成"0,1"分布数据表,然后进行聚类分析.根据聚类结果,参考地理、气候、茶树的种植历史和种植面积以及其他动物类群方面的研究和前人的工作,把湖南省茶树害虫分成4个区:湘北环湖平原丘岗区,湘中、湘东丘陵区,湘西山区,湘南山地丘陵区,并分别叙述了各区的特点.     

Preliminary Studies on Flavour Volatiles in Qimen Black Tea

Three kinds of flavor enriched black tea in the world are produced from Qimen in China, Darjeeling in India and Uva in Sri Lanka. The results of analysis from the Qimen black tea showed that there are more than twenty flavour volatiles. The essential aromatic compounds are geraniol, 2,6-di-butul-l,4-benzoquinone, 2,6-di-t-butyl-4-methyl phenol, benzenemethanol, benzenethanol, linalool and linalool oxides. In Qimen black tea the aroma acquired is produced during the processing aside from the original compounds of fresh leaves.     

黄土高原丘陵区不同生境小叶杨人工林物种多样性及其群落稳定性分析

通过样地调查,对黄土高原丘陵沟壑区处于阴坡、半阴坡、半阳坡、阳坡4种生境条件下,经过30年发育的小叶杨人工林物种多样性,群落结构动态和土壤水分养分效应进行了系统研究,结果表明:(1)不同生境小叶杨人工林总体上物种丰富度、多样性指数和均匀度指数均呈现出阴坡>半阴坡>半阳坡>阳坡的趋势,且林内物种多样性指数表现为:草本层>灌木层;(2)不同生境条件下的小叶杨人工林年龄结构分析表明,尽管阴坡小叶杨长势相对较好,但更新幼苗数量相当有限,很难实现种群的自我更新,不适合作为人工林培育;(3)土壤含水量和养分因坡向不同而呈现出明显的差异,尽管阴坡和半阴坡的水分、养分条件相对较好,但也出现了枯梢、病虫害等衰老特征,因此阴坡、半阴坡的生境对小叶杨来说也不合适.未来应该对现有林地在保护的前提下,间伐衰老个体,补植和引入乡土物种,进行天然化培育.     

林茶间作下的光照条件与茶树生理生态研究综述

林茶间作下的光照条件与茶树生理生态研究综述周志翔（华中农业大学林学系,武汉４３００７０）ＲｅｖｉｅｗｏｎＬｉｇｈｔＶａｒｉａｔｉｏｎｉｎＴｅａａｎｄＯｔｈｅｒＷｏｏｄｙＰｌａｎｔｓＩｎｔｅｒｃｒｏｐｐｅｄＰｌａｎｔａｔｉｏｎｓａｎｄＥｃｏ－ｐｈｙｓｉ...     

不同茶园灰茶尺蠖和茶尺蠖对5种杀虫剂的抗药性监测

为了明确茶园暴食性害虫灰茶尺蠖Ectropis grisescens和茶尺蠖E. obliqua抗药性现状,制定有效的防治措施,本研究采用浸叶法分别测定了5种茶园常用杀虫剂对5个地理种群灰茶尺蠖和2个地理种群茶尺蠖的抗药性。结果表明,不同茶园灰茶尺蠖和茶尺蠖对供试药剂的抗性水平存在差异：浙江兰溪、浙江金华、河南南阳地区的灰茶尺蠖种群和浙江杭州、浙江安吉的茶尺蠖种群对联苯菊酯产生了中高等抗性;浙江杭州的茶尺蠖种群对苦参碱的抗性达到中等水平,其余供试种群对苦参碱抗性处于敏感水平;所有供试种群对虫螨腈、甲氨基阿维菌素苯甲酸盐和茚虫威这3种药剂的抗性均处于敏感水平。从化学防治的角度来看,目前茶园灰茶尺蠖和茶尺蠖对虫螨腈、甲氨基阿维菌素苯甲酸盐和茚虫威敏感性高,抗性低,推荐合理科学使用,并避免长期使用单一农药。     

Tea consumption reduces ovarian cancer risk

Objective: To ascertain the relationship between tea drinking and the risk of ovarian cancer among southern Chinese women, a case–control study was conducted in southern China during 2006–2008. Methods: Five hundred incident patients with histologically confirmed epithelial carcinoma of the ovary and 500 controls (mean age 59 years) were recruited from four public hospitals in Guangzhou. Information on frequency, quantity and duration of tea drinking, amount of dried tea leaves brewed, together with habitual diet and lifestyle characteristics, was obtained face-to-face from participants using a validated and reliable questionnaire. Logistic regression analyses were performed to assess the association between tea consumption variables and the ovarian cancer risk. Results: The control subjects reported higher tea consumption levels and prevalence (78.8%) than the ovarian cancer patients (51.4%). Regular drinking of green tea, black tea and/or oolong tea was associated with a lower risk of ovarian cancer, the adjusted odds ratio being 0.29 (95% confidence interval 0.22–0.39) after accounting for confounding factors. When compared with non-drinkers, apparent inverse dose–response relationships were observed for years of drinking, number of cups and quantity of tea consumed, as well as amount of dried tea leaves brewed (p < 0.01). Conclusion: Regular tea consumption is associated with a reduced risk of ovarian cancer for southern Chinese women.