Insecticidal properties of <Emphasis Type="Italic">Thymus persicus</Emphasis> essential oil against <Emphasis Type="Italic">Tribolium castaneum</Emphasis> and <Emphasis Type="Italic">Sitophilus oryzae</Emphasis>

Red flour beetle Tribolium castaneum (Herbst) and rice weevil Sitophilus oryzae (L.) are considered to be the major insect pests in storage. Essential oils from aromatic plants are recognized as proper alternatives to fumigants. Thymus persicus (Ronniger ex Rech. f.) is one of these plants that have medicinal properties and is indigenous to Iran. The essential oil was obtained from aerial parts of the plant and analyzed by GC and GC–MS. Carvacrol (44.69%) and thymol (11.05%) were the major constituents of the oil extracted. In this experiment, fumigant toxicity of the essential oil was studied against T. castaneum, S. oryzae at 27 ± 1°C and 60 ± 5% RH in dark condition. The adult insects were exposed to the concentrations of 51.9, 111.1, 207.4 and 370.4 μl/l air to estimate median lethal time (LT₅₀) values. The fumigant toxicity was increased in response to increased essential oil concentrations. The LT₅₀ values at the lowest and the highest concentrations tested were ranged from 28.09 to 13.47 h for T. castaneum, and 3.86 to 2.30 h for S. oryzae. It was found that S. oryzae adults were much more susceptible to the oil than T. castaneum. After 24 h of exposure, the LC₅₀ values (95% fiducial limit) for T. castaneum and S. oryzae were estimated to be 236.9 (186.27–292.81) and 3.34 (2.62–4.28) μl/l air, respectively. These results suggest that T. persicus essential oil merits further study as potential fumigant for the management of these stored-product insects.     

Determinants of the biodiversity patterns of ammonia-oxidizing archaea community in two contrasting forest stands

Purpose

The variation in soil microbial community patterns is primarily influenced by ecological processes associated with spatial distance and environmental heterogeneities. However, the relative importance of these processes in determining the patterns of soil microbial biodiversity in different successional forests remains unclear.

Materials and methods

Based on the species data from denaturing gradient gel electrophoresis (DGGE) analysis, we described the composition and beta diversity of ammonia-oxidizing archaea (AOA) community, an important functional microbial group in regulating nitrogen cycle, in a middle-succeed stand (60 years of secondary succession) and an undisturbed native stand in a subtropical forest in southern China. The composition pattern was examined using a multi-response permutation procedure (MRPP), and the beta diversity was described using the Sørensen index. The relative influence of edaphic, vegetational, spatial, and topographical factors on AOA composition and beta diversity was assessed by variation partitioning and multiple regression on distance matrices (MRM), respectively.

Results and discussion

We did not find any stand-specific patterns in AOA community composition in the two stands; however, the influential variables were different between the two stands; 7.3 and 4.5 % of the total variation in AOA community composition could be explained by edaphic (i.e., available potassium and total phosphorus) and spatial variables, respectively, in the middle-succeed stand, while 3.7 and 2.8 % of the variation were explained by spatial variable and available phosphorus, respectively, in the native stand. Soil total phosphorus influenced the beta diversity of AOA community most in the middle-succeed stand, while genetic distance of tree species was found to be the most important factor in driving the beta diversity pattern in the native stand.

Conclusions

Soil nutrients influenced the beta diversity of AOA community in the middle-succeed stand more than that in the native stand, while vegetation is more important in the native stand. The substantial unexplained variations were possibly due to the effects of other unmeasured variables. Nevertheless, dispersal process is more important in controlling AOA community composition in the native stand, while processes associated with environmental heterogeneities are more important in the middle-succeed stand in this subtropical forest.

     

Evaluation of genetic and non-genetic factors on foot and mouth disease (FMD) virus vaccine-elicited immune response in Hardhenu (<Emphasis Type="Italic">Bos taurus</Emphasis> x <Emphasis Type="Italic">Bos indicus</Emphasis>) cattle

Foot and mouth disease (FMD) is the most contagious disease of mammals and a major threat to animal husbandry sector. In India, vaccination with the inactivated trivalent (O, A and Asia1) vaccine is one proven way for protecting the livestock from FMD. However, many outbreaks have been reported in different parts of the country. Therefore, present study was aimed at elucidating the effects of genetic and non-genetic factors on FMD viral vaccine-elicited immune response in Hardhenu cattle. The effect of season of vaccination was not consistent. The effect of status of animal was significant for all the pre and post AB titres except for pre AB titre of serotype O and post AB titre of Asia1.The estimates of heritability for response to vaccination were low to high ranging from 0.11 to 0.45. The highest heritability estimate was obtained for serotype O and the lowest for Asia1. The heritability estimates for pre and post AB titres ranged from 0.15 to 0.33. All the pre and post AB titres and responses to vaccination had genetic correlations ranged from high negative to high positive among them. Results of this study highlight the variation in vaccine response which needs to be further exploited on large-scale animal data for better immunization and protection against highly contagious viral vesicular disease of cloven-hoofed animals.     

Achieving food and nutritional security through agroforestry: a case of <Emphasis Type="Italic">Faidherbia albida</Emphasis> in sub-Saharan Africa

Faidherbia albida is an ideal agroforestry tree commonly intercropped with annual crops like millet and groundnuts in the dry and densely populated areas of Africa. With its peculiar reverse phenology, it makes growth demands at a different time from that of crops. In addition, it deposits great amount of organic fertilizer on food crops. Leaves entering soils are comparable to fertilization of almost 50 t·ha 1 ·year 1 of manure in dense stands of 50 large trees per ha. These nutrients help maximize agricultural production and reduce the need for a fallow period on poorer soils. Research has shown that millet grown under F. albida yielded 2.5 and 3.4 fold increases in grain and protein, respectively. Animals eat pods which contain mean amounts of crude protein of 20.63% and carbohydrate of 40.1% in seeds. Moreover, the continued existence of F. albida in agroforestry parklands as in Ethiopia and Mali signifies the success of traditional conservation measures. Modern scientists have also developed much interest in the role of agroforestry in maintaining long-term biological balance between agriculture and livestock production systems. To ensure food security, which still remains a major challenge in sub-Saharan Africa, and concurrently minimize environmental degradation, promotion of agroforestry that specifically involves indigenous trees is crucial. We discuss the prospective role of F. albida in alleviating poverty while simultaneously protecting the environment from factors associated with, for example, deforestation and loss of biodiversity. The overall aim is to promote wide-scale adoption of F. albida as a valuable tree crop in farming systems, particularly in those areas where it remains unexploited.     

Drivers of adoption of eucalypt tree farming by smallholders in Thailand

Eucalypt (Eucalyptus spp.) tree farming is a source of income for many smallholders in developing and emerging countries and critical to the resource supply of many pulp and paper companies. These companies rely on smallholders adopting tree farming, sometimes by offering a contract. This paper reports a study from four regions of Thailand, where smallholder eucalypt tree farming is important, which investigated what characteristics of smallholders were associated with greater adoption of tree farming. A total of 461 eucalypt tree farmers and 171 non-tree farmers were randomly selected and surveyed in these regions, using a door-to-door household survey. A logit analysis corroborated hypotheses about the drivers of adoption. Qualitative analyses were used to inform interpretation of the quantitative results and shed light on the role of eucalypt tree farming in smallholders’ livelihood. Results demonstrate that those with suitable land available are more likely to adopt eucalypt tree farming than others. In addition, perception of land tenure security matters in the adoption of tree growing, but holding a formal land tenure document does not. Adoption of eucalypt tree farming in Thailand is not part of a land use intensification strategy. Instead, eucalypts are used as an alternative crop for low productivity land, on which eucalypts are the most profitable crop. Eucalypt tree farming also gives smallholders an opportunity to diversify their income. In addition, this alternative land use has the advantage of requiring low labour inputs between planting and harvest. This is particularly advantageous for many tree growers who have off-farm income or rely on hired labour for farming their land.     

Avian predation on wild and cultured sea urchin <Emphasis Type="Italic">Strongylocentrotus intermedius</Emphasis> in a rocky shore habitat

ABSTRACT:   The present study reports the annual variation in consumption of the sea urchin Strongylocentrotus intermedius by avian predators on a rocky shore where the culture of sea urchins has been conducted. Carrion crow and a few gull species were the most abundant avian predators and consumed a large number of sea urchins. Crows consumed mostly natural sea urchins, approximately 36 kg ww/ha per year on the intertidal rocky bench, but the gull species consumed mostly cultured sea urchins, approximately 100 kg ww/ha per year in the culture area. The seasonal variation in the amount of sea urchins consumed by crows was higher than that by the gull species, presumably because of the difference in foraging behavior in association with the seasonal tidal cycle. The natural sea urchins consumed are an allochthonous input from the subtidal to the intertidal habitat, and thus, crow predation may not affect the natural and the cultured populations of the sea urchin. The gull species consumed much of the cultured sea urchin, and thus, may be regarded as an effective predator causing damage to sea urchin culture. The results suggest that further studies are needed to determine why the gull species selectively feed on cultured sea urchins.     

四川柑橘适宜分布及其对气候变化的响应研究

柑橘是四川省和我国主要水果产品之一。以气候为主的环境变化,对作物空间布局产生了显著影响。为合理优化柑橘生产空间,本研究基于最大熵模型（MaxEnt）构建柑橘适宜分布与环境变量的关系模型,运用受试者工作特征曲线（ROC曲线）检测模型精度,刀切法（Jackknife）筛选主导环境变量;采用ArcGIS技术对比1980年、2010年四川柑橘适宜区分布,揭示近30 a气候变化背景下四川省柑橘适宜区的分布与变化情况。结果显示：四川柑橘适宜性的主导环境变量主要体现为以光、热、水为特征的气候环境变量。近30 a四川省气候暖干化的变化趋势改变了区域生态系统的结构和功能,引起了柑橘种植适宜区的时空变化。1980—2010年柑橘种植适宜性空间格局呈现出2个变化特征,一是高适宜区呈整体向北迁移的趋势,主要分布在成都平原区与川东北地区过渡地区;中适宜区界线向东南方迁移。二是适宜性级别呈现出逐级调整,低、中适宜区的等级调整变化明显。2010年高适宜区面积约为4.22万km²,中适宜区4.19万km²,低适宜区4.4万km²,大部分地区为不适宜区。以高适宜区为参照,通过政策措施,政府部门可增加在川南地区、成都平原地区南部的柑橘生产布局。本研究客观地反映了气候变化下,四川省柑橘种植适宜性变化特征,合理确定了柑橘适宜性面积及分布,为柑橘空间优化提供了科学依据。最大熵模型在对物种分布进行准确模拟和预测时具有较强应用价值,对作物气候适宜性区划具有重要指导意义。但对于不同区域和作物应选取合适的环境变量、空间尺度和物种采样位置,减少系统累计误差,提高作物气候适宜区划定精度。     

不同灌溉处理寒地井灌稻田地温和产量构成要素研究

通过田同试验研究了浅水-间歇灌溉（SIT）、湿润-间歇灌溉（MIT）、淹灌（CSF）条件下寒地稻田的0～ 15 cm地温和水稻产量构成因素.结果表明,SrT、MIT田间建立浅水层或无水层,有利于0～ 15 cm的土壤温度的提升.由于Srr和MIT处理显著提高了每穴有效穗数,因而最终分别较CSF增产8.6％和11.9％,但SIT和MIT处理间差异不显著.