The shoot-feeding ecology of three Tomicus species in Yunnan Province,southwestern China

Three Tomicus pine shoot beetles, T. yunnanensis (Kirkendall and Faccoli) (Coleoptera: Scolytidae), T. minor (Hartig), and T. brevipilosus (Wood and Bright), have been causing serious damage to Yunnan pine ( Pinus yunnanensis (Franchet) (Pinales: Pinaceae)) stands in Yunnan, southwestern China. However, their ability to coexist in the crowns of the same trees during the shoot-feeding phase has not been elucidated. In our study, we investigated and compared the shoot-feeding ecology of the three species of pine shoot beetle in P. yunnanensis in Anning County, Yunnan Province. Shoot-feeding by T. yunnanensis, T. minor, and T. brevipilosus initiated in April, May, and June, and ended in February, April, and May, respectively. Individual T. yunnanensis and T. minor adults fed in shoots for about seven months, and T. brevipilosus for nine months, before initiating reproduction. All three Tomicus species fed in the current-year shoots close to the apical bud. No specific overwintering behavior was observed prior to reproduction. The entrance hole of T. yunnanensis was furthest away from the apical bud, and T. minor was the closest to the apical bud. Differences in the spatial distribution of these shoot-feeding sites might reduce competition among the three beetle species. The long-lasting and overlapping shoot-feeding by the three Tomicus species may reduce the resistance of P. yunnanensis and facilitate the reproduction of these beetles in the trunks of living trees, and thus help explain the severe damage by Tomicus in P. yunnanensis.     

四川省灌溉管理节水发展水平综合评价模型构建与应用

灌溉管理节水发展水平评价是制定区域节水灌溉发展规划的重要决策依据。该文采用定量指标和定性指标相结合的方法建立了包括组织管理、工程管理、用水管理和经营管理4个层次16项指标的区域灌溉管理节水发展水平综合评价体系,在此基础上构建了四川省灌溉管理节水发展水平综合评价模型;引入熵权法和层次分析法计算各评价指标权重,提高了权重确定的科学性与客观性。以四川省21个市州(区域)为研究对象,利用模型通过形成决策矩阵、确定权重、建立加权决策矩阵、计算各评价对象与理想解的相对贴进度,由此得到四川省不同区域灌溉管理节水发展水平。结果表明:四川省全省灌溉管理节水发展处于"一般"水平;21个区域中,成都、德阳处于"好"水平,攀枝花、绵阳、资阳、乐山处于"较好"水平,自贡等10个区域处于"一般"水平,广元、内江处于"较差"水平,甘孜、阿坝、凉山处于"差"水平;以上结果符合四川省灌溉管理节水发展的实际情况;模型对于四川省灌溉管理节水发展具有较强的实用性。     

棉花种植方式的优化选择

根据新疆生产建设兵团29团大面积推广应用农业高新技术的调查，特别是棉花大面积不同品种、不同种植、灌溉方式的产量结构和实际产量的调查，提出了棉花种植方式的优化选择问题，即采用膜下滴灌技术，采用68cm 8cm的宽窄行、适宜机采棉的株行距，选用结铃性强、适于机械采收的棉花品种是目前棉花较好的配置选择。     

自然风景质量评价研究——BIB-LCJ审美评判测量法

本文分析了目前世界上公认最好的两种风景审美评判测量法(SBE法和LCJ法),综合了两者的优点,同时消除其缺点,提出了BIB—LCJ一种新的评判方法.应用BIB—LCJ法研究了公众、专家、非专业学生和专业学生在风景审美方面的特点及相互关系。刺激是一组湖泊风景(N=49)。应用计算机”ANALYST”软件包进行分析表明:不同类型的人之间,在自然风景的审美评判方面有普遍的一致性;同时,在某些方面又各有特点。     

食蚜瘿蚊对3种蚜虫捕食作用的研究

[目的]为评价和充分利用食蚜瘿蚊的控蚜作用。[方法]将甘蓝蚜、桃蚜、蔷薇长管蚜分别设置5个密度,并用甘蓝蚜作种内干扰竞争试验,研究食蚜瘿蚊对3种蚜虫的捕食作用。[结果]食蚜瘿蚊对甘蓝蚜、桃蚜、蔷薇长管蚜的捕食功能反应均符合HollingⅡ型方程。食蚜瘿蚊对甘蓝蚜、桃蚜、蔷薇长管蚜一昼夜的捕食上限分别为13、11、12头,猎物密度相同时对甘蓝蚜的寻找效应始终高于桃蚜和蔷薇长管蚜。食蚜瘿蚊幼虫有较强的种内干扰反应,平均捕食量随自身密度的增大逐渐减少。[结论]食蚜瘿蚊的捕食数量随蚜虫密度的增加而增加,寻找效应随蚜虫密度的增大而降低。食蚜瘿蚊对甘蓝蚜的捕食量最高,捕食率随自身密度的增大而降低。     

Effects of low pH environment on the collembolan Onychiurus yaodai

The effects of pH on taxis, mortality and activation of MAP-kinase pathways in the collembolan Onychiurus yaodai were studied. The animals preferred to stay at pH 8. They were particularly stressed by a reduction in pH but were more tolerant of elevated pH. A short period of exposure to low pH led to phosphorylation of Drosophila homolog of extracellular signal-regulated kinase (ERKa) and the c-Jun N-terminal kinase (DJNK) in the animals, indicating activation of these signal transduction pathways. Our observations suggest that reduced environmental pH, even for a limited period, is potentially harmful to O. yaodai.     

Intake, liveweight gain and feed preference by steers fed combinations of lucerne and Westerwolds ryegrass silages

Nutritive value and voluntary intake of legumes are generally considered to be higher than those of grasses when ensiled at similar digestibility, although high levels of soluble protein can result in low N utilization by animals and high losses to the environment. The objectives of this experiment were to describe the optimum combination of Westerwolds ryegrass ( Lolium multiflorum Lam. cv. Aubade) and lucerne ( Medicago sativa L. cv. AC Caribou) silages to maximize liveweight gain of steers fed silage, determine chemical components that are important and ascertain whether steers selected the optimum mixture when given a choice. Both silages contained similar concentrations of dry matter (DM), acid-detergent fibre (ADF) and organic acids, but lucerne silage had higher concentrations of N, soluble-N and ammonia-N. Westerwolds ryegrass silage contained more neutral-detergent fibre (NDF). In a 12-week experiment, voluntary intake by Hereford steers was not influenced when the proportion of the two silages was changed from 1 to 0 in 0·25 increments. However, liveweight gain and feed efficiency increased linearly ( P  < 0·001) as the proportion of ryegrass silage fed was increased. When preconditioned to either of the two silages, steers showed a significant preference for ryegrass over lucerne ( P  < 0·05). When conditioned to a mixture of both silages, no preference was elicited. It is suggested that extensive solubilization and deamination of protein in the lucerne silage may have caused the preference for Westerwolds ryegrass silage and the higher liveweight gains on diets containing higher proportions of Westerwolds ryegrass silage.     

桃树蚜虫调查及药效与安全性评价

旨在明确桃树蚜虫为害特点,调查了不同品种桃树蚜虫种类、数量及为害差异.利用喷雾法比较了4种药剂对桃蚜的防治效果;对药后21天捕食性天敌数量和种类、优势度、主要天敌虫态情况及不同药剂浓度对天敌影响进行比较.结果表明:(1)就种类而言,油桃和毛桃以桃蚜为主,碧桃以桃粉蚜为主;数量而言,油桃桃蚜占95.4％,显著高于桃粉蚜,...     

Nitrogen source and aluminum toxicity of two sorghum genotypes differing in aluminum susceptibility

After a 35 days growth on nutrient solutions with NO^‐ ₃ NH₄NO₃ and NH⁺ ₄ as nitrogen source (pH 4.2) dry matter yield of the sorghum genotype SC0283 was much less affected by Al (1.5 mg‐¹) than that of the genotype NB9040. With NO^‐ ₃ as the sole nitrogen source only growth of the NB9040 plants was significantly reduced. Since OH^‐ efflux, shoot Al content and concentrations of all major nutrients of both genotypes were almost equal, a higher sensitivity to Al may underlie the lower Al tolerance of the NB9040 genotype. In the presence of NH.‐N Al again lowered d.m. yield of the NB plants. With SCO283 significant Al effects on d.m. yield were observed only with NH₄NO₃. Aluminum drastically increased the amount of protons released per unit of root surface area, especially with the NB9040 line. This shift in proton flux density was partly the result of a decrease of the specific root surface area and partly due to enhanced excess of catlonic nutrients taken up. With NH₄NO₃‐fed plants the latter could almost completely be attributed to a changed N preference brought about by inhibited uptake of NO^‐ ₃ and a simultaneous enhanced NH, absorption. Although both proton efflux and NH⁺ ₄ preference of the NB plants were severely increased by Al, relative yields of this genotype were not lowered by NH⁺ _4. This can probably be explained by (1) the high NH, sensitivity of this cultivar through which Al effects can be masked and (2) the continuous adjustment of the solution pH through which rhizosphere conditions were prevented.     

Trends in Information Needs and Communication Channel Use Among Rural Women in Africa,Asia, and Latin America, 2000–2012

A trend analysis of information needs and communication channel use of rural women in Africa, Asia, and Latin America was conducted by examining empirical works published in reports, scholarly publications, and the popular press from 2000 to 2012. Results show that information about farming practices, health, education, gender and general family well-being issues were the most sought across the three continents. Demand for 14 information categories surged in volume and scope after 2009. Interpersonal communication sources trumped the mediated ones as the channels of choice; extension agents were the most preferred source. Radio was the most frequently mentioned preferred medium.