灰色灾变理论在宁南山区干旱气候预测中的应用

在分析宁南山区干旱气候特征及其对农业生产影响的基础上 ,借助灰色灾变理论分别建立了春旱、夏旱、秋旱、春夏连旱、夏秋连旱、全年旱等六种干旱类型的 GM( 1 ,1 )预测模型 ,并对 2 0 0 0～ 2 0 2 0年的干旱气候做出预测。经对 2 0 0 0年和 2 0 0 1年预测结果验证 ,吻合性良好。此外 ,提出了宁南山区抗旱防旱的综合农业措施。研究结果可对广大旱区抗旱减灾 ,促进农业生产发展提供科学指导。     

宁夏南部山区生态环境建设与科技扶贫战略研究

干旱、低产、人口膨胀，是造成宁南山区生态环境恶化和经济发展缓慢的重要原因。在基本解决温饱的基础上，抓住西部大开发历史机遇，以生态环境建设为切入点，以发展集水型庭园经济为突破口，以提高劳动者素质和致富技能为本，依靠科技进步，推进农业结构调整，合理配置水土资源和劳动力资源，形成具有区域特色和市场竞争力的民族经济体系与可持续发展模式，应是宁南山区的战略目标。分别论述了3个类型区建设与发展的技术关键，为宁南山区生态环境建设与科技扶贫开发提供决策依据。     

论宁南旱区农业技术

基于旱区范围趋于扩大、干旱程度趋于严重等的干旱发展趋势，以及农业有限水量应能实现的生产能力，尚远示成为现实生产力的实际，分析了节水型农牧生产结构、耐旱型的种植业结构、径流农业技术、蓄水保墒技术改进、灌溉农田效益增进、抗旱化学制剂应用，以及宁南地域资源优势等有关整体技术宏观块择和单一旱作技术的结合，在宁南旱农生产中的作用及进一步发展前景。     

宁南山区土地利用和开发战略探讨

宁南山区地表结构复杂，是典型的温带大陆性半干旱偏旱季风气候。在调查分析土地利用现状特点和存在问题的基础上，提出统一规划，合理布局；增加肥料投入，改良培肥土壤；推广和使用旱作农业丰产技术，发展集流农业和节水灌溉技术；开发区域名优特产，建立绿色食品生产基地；以饲草生产为突破口，加速发展畜牧业经济的区域土地开发战略措施。     

宁夏南部山区旱作农业开发战略研究

宁夏南部山区属半干旱区 ,90 %以上的耕地为旱地 ,加速旱作农业开发 ,对促进该区域经济全面发展具有十分重要的战略意义。本文论述了旱作农业开发在宁南山区的地位与潜力 ,提出了相应的技术需求。针对区域资源特点提出该区域旱作农业开发的三个战略阶段 :即强农促牧、农牧并举和稳农重牧阶段     

宁南农业持续力及持续发展

依据宁南资源特点及土地承载力，分析了宁南农业的持续能力及障碍因素。宁南光热资源丰富、土地广阔、降水生产潜力大、有一批稳定的科技队伍及较高水平的科技贮备，具有农业持续发展的物质基础和条件，但生态环境恶劣、自然灾害频繁、人口增长过快、农业投入不足，又是农业持续发展的主要障碍因素。为此，应采取退耕还林还牧、严格控制人口、强化农业投入、发展宁南优势产业的持续发展战略及技术。     

宁南旱地小杂粮产业开发技术研究

立足宁南旱地小杂粮生产现状,通过分析影响产业化发展的主要限制因子,提出了以持续增进降水生产潜力,提高降水利用率和农田水分效率为重点,大力推广优质高效抗旱新品种及配套栽培技术、优化集成抗旱节水农业技术、培肥土壤、建设高产稳产基本农田、加强产业化开发等关键技术。     

宁南山区苜蓿产业化生产浅析

通过对宁南山区发展苜蓿及其产业化生产的气候条件和市场前景等有关因素及存在问题的深入分析，指出发展苜蓿产业化生产是刺激当地生态农业和经济结构调整的必由之路，并提出了宁南山区积极推进苜蓿产业化生产的发展对策。     

宁南山区农业发展的困境与出路

通过对宁南山区农业现状的分析表明，人口超载，水土流失和自然灾害频繁是制约宁南农业发展的主要障碍，同时也可以看出，随着农业基础设施的不断建设，农业生产力潜力还很大，控制人口保持水土和发展宁南草牧业是摆脱农业发展困境的战略举措。     

宁南旱作土壤培肥途径及技术研究

根据宁南山区的实际情况，在注重生物培肥的同时，应适量增加化肥投入，走有机与无机相结合的培肥土壤的途径。适当当地生物培肥土壤的措施有：合理轮作，增施有机肥，夏季绿肥压青和秸秆还田等，其中以合理轮作更具有现实性和普遍意义。     

Hymenopteran Parasitoids on Fruit-infesting Tephritidae (Diptera) in Latin America and the Southern United States: Diversity, Distribution, Taxonomic Status and their use in Fruit Fly Biological Control

We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.     

Brief Guide for Authors

正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad     

The parasitoid complex ofLiriomyza cicerina on chickpea (Cicer arietinum)

Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.     

Plant–herbivore asynchrony necessitates augmentative releases of the exotic beetle,Zygogramma bicolorata,to enhance the biological control of P arthenium hysterophorus

Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F ₃, F ₄ and F ₅, but not in F ₁ and F ₂ that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F ₁ and F ₂ in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.     

Richtlinien der Verbände des ökologischen Landbaus zum Vorratsschutz

Zusammenfassung Verbände des ökologischen Landbaus wie z. B. Bioland, Gäa, Demeter; Naturland, Ernte für das Leben oder Bio Suisse beschränken ihre Mitglieder bei der Wahl von Vorratsschutzmaßnahmen. Vorrang besitzen Maßnahmen zur Vermeidung von Schädlingen gegenüber Bekämpfungsmaßnahmen. Fallen müssen zur Befallsüberwachung eingesetzt werden, um einen Befall durch Vorratsschädlinge frühzeitig zu erkennen. Diese Maßnahmen sollen den weitgehenden Verzicht auf chemisch-synthetische Mittel ermöglichen. In diesem Beitrag werden die Empfehlungen der Verbände mit den derzeit verfügbaren chemischen Mitteln für den Vorratsschutz abgeglichen. Erfahrung in der praktischen Umsetzung von physikalischen und biologischen Verfahren werden diskutiert und Defizite bei der Befallsüberwachung und Bekämpfung beschrieben.     

Development of protocols for detection of Colletotrichum acutatum and monitoring of strawberry anthracnose using real-time PCR

Real-time PCR (TaqMan®) assays were developed for the specific detection and discrimination of Colletotrichum spp., C. acutatum and C. gloeosporioides causing anthracnose in strawberry using the most divergent area of the internal transcribed spacers (ITS1 and ITS2) and 5·8S ribosomal RNA (rRNA) gene region. The specificity of the new assays was tested using DNA from six species of Colletotrichum and nine fungal species commonly found associated with strawberry material, and additionally by comparing the sequences with those from databases using a blast search. The sequences only showed identity with homologous sequences from the desired target organisms. The new assays were 10–100 times more sensitive than conventional PCR methods previously published for the diagnosis of strawberry anthracnose. When real-time PCR was compared with ELISA methods, PCR improved the sensitivity of the identification by obtaining positive results for samples of strawberry plant material that tested negative with ELISA. The development of C. acutatum was monitored using artificially infected strawberry crowns from two strawberry cultivars (Camarosa and Ventana) and a real-time PCR assay specific for this species between January and June 2006. The amount of C. acutatum detected using real-time PCR varied significantly by month ( P  < 0·001), but not by cultivar ( P  = 0·394). The new assays were shown to be useful tools for rapid detection and identification of these pathogens and to allow rapid and accurate assessment of the casual agents of anthracnose in strawberry.     

Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

The effects of the saprophytic mycoflora and its interference with cereal aphids on growth and yield of winter and spring wheat was studied in field experiments in 1980, 1981 and 1982.Yields varied between 5000 and 8000 kg dry matter of kernels per ha. The effect of the saprophytic mycoflora on yield was determined in different treatments: A) no control measures against cereal aphids and saprophytic and necrotrophic fungi, B) no control of cereal aphids, control of saprophytic and necrotrophic fungi, C) control of cereal aphids and control of saprophytic and necrotrophic fungi, D) control of cereal aphids and stimulation of saprophytic mycoflora and E) control of cereal aphids, no control of saprophytic and necrotrophic fungi nor stimulation of saprophytic mycoflora.Considerable differences in top densities of saprophytic mycoflora (10 times as large in A and D as in B and C) were determined. The consequences of these differences for the growth and productivity of wheat were minor. A negative effect of saprophytic mycoflora on the yield could not be detected in 1981 and 1982, whereas a small positive significant effect was found in 1980. This stimulation may have been due to competition between necrotrophic fungal pathogens and saprophytic mycoflora. As a result of favourable weather conditions necrotrophic fungal pathogens were very numerous in 1980 and could form an important yield reducing factor. Yield levels may effect the importance of the necrotrophic and saprophytic mycoflora as yield reducing factors. Additionally, in the presence of aphid honeydew captafol was found to be relatively ineffective against saprophytic fungi.     

Relationship Between Production of the Phytotoxin Prehelminthosporol and Virulence in Isolates of the Plant Pathogenic Fungus Bipolaris sorokiniana

A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5ngl^–1 (signal to noise ratio 4:1) which corresponds to ca. 15ng prehelminthosporol per mg dry weight of mycelium or 15ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.