烟草黑胫病菌(Phytophthora parasitica var. nicotianae)生理小种鉴定技术研究

在1980-1986年,对烟草黑胫病菌生理小种鉴定技术和方法进行了研究和探讨。结果表明,Nicotiana ncsophil(?),Burley21;Burley37;N.stocktonii是理想的鉴别寄主:整株接种方法优于其他的接种方法;接种物浓度以控制在相同的水平(10~3 ml)为宜。为减小生物测定的差异,所有菌系应一次完成测定。     

新疆哈密瓜疫病掘氏疫霉及寄主范围的初步研究

据1981～1983年9个哈密瓜生产基地根颈部病害的病原成份调查表明,哈密瓜疫病的优势种为掘氏疫霉菌(Phytophthora drechsleri Tucker.)。为澄清在新疆掘氏疫霉的寄主范围,1989～1990年用1981年采自鄯善县哈密瓜上分离的单孢(Phy-6)菌株,在温室平均温度25～28℃条件下对5科25种自然根颈感病的栽培作物作接种试验。结果表明,本菌是葫芦科大多数作物的重要致病菌,并可侵染棉花和红花;在有伤口条件下可以侵染南瓜、西葫芦和茄株;对苦瓜、丝瓜,豆科作物的豇豆、四季豆、菊科的向日葵、茄科的蕃茄、辣椒、烟草、马铃薯、蔷薇科草莓(植株)等均不能致病。     

实验猴志贺氏菌检出、血清分型及药物敏感性试验

采用实验动物国家标准(GB/T 14926.47-2001)的检验方法,对144份待出口实验猴粪便样品检测,检出志贺氏菌2株,阳性检出率1.39%。血清学分型,均属于B群志贺氏菌,血清型分别为X变种和Y变种。药敏试验结果表明,2株分离菌对先锋V、氟哌酸和环丙沙星高度敏感,而对青霉素、红霉素和复方新诺明耐药。     

Landscape-ecological mapping of the Netherlands

The Landscape-ecological Mapping of the Netherlands project (LMN project) started in 1983 with the aim of establishing a landscape-ecological database for use in developing and evaluating national land-use plans. The project, working with grid cells of 1 km², has four working objectives: a) development of mapping potential for basic landscape-ecological data, b) assessment of susceptibility to interventions, c) evaluation of significance for nature conservation and d) production of vulnerability maps, as a combination of susceptibility and significance. In addition to information on soil, groundwater, ecotopes, flora and fauna, the database also incorporates information on physiographical features and entire landscapes. The resulting database is a geographic information system (GIS). This article describes the second phase of the project (1985–1989), covering the Randstad area, and focusses on the methods and the applications potential of the database.     

Red rice (Oryza sativa L.) and barnyardgrass (Echinochloa spp.) biotype susceptibility to postemergence-applied imazamox

Pot experiments were conducted to evaluate the level of imazamox tolerance in five red rice ( Oryza sativa L.) and four barnyardgrass (three Echinochloa crus-galli (L.) Beauv. and one Echinochloa oryzoides (Ard.) Fritch) morphologically distinct biotypes collected from rice fields in northern Greece. The susceptibility of barnyardgrass biotypes to propanil was also studied. Red rice biotypes were not controlled by imazamox applied at 40 g ha⁻¹. In contrast, 80 g imazamox ha⁻¹ provided 56–84% red rice control (averaged across shoot number and fresh weight reduction). Not all barnyardgrass biotypes were susceptible to imazamox applied postemergence. However, propanil applied at 2.6 kg ha ⁻¹ controlled the E. crus-galli biotypes well, but propanil applied at rates of 2.6 and 5.2 kg ha ⁻¹ was not effective in reducing the shoot number and fresh weight of the E. oryzoides biotype. Propanil applied at 10.4 kg ha ⁻¹ reduced the shoot number and fresh weight of this biotype by 78 and 85%, respectively. In most cases, a linear equation ( y  = % of control, x  = g ha⁻¹) provided the best fit for regressions between red rice or barnyardgrass shoot number or fresh weight and imazamox rates. The results of this study suggest that postemergence application of imazamox is not effective against all red rice and barnyardgrass biotypes found in the rice fields of Greece and that significant variability regarding herbicide efficacy among biotypes might exist.     

The Biology of the Larger Grain Borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae)

After about 25 years of intensive research a substantial moment of information has accumulated on the basic biology of Prostephanus truncatus in stored products. This article reviews the literature on the geographical distribution, biotypes, symbiotic associations, mating and flight behaviour, oviposition, and development on both agricultural and non-agricultural hosts. The current knowledge about the nutritional biology (including the role of symbionts) and host finding behaviour (including the inter-linked roles of plant chemicals and the insect's own pheronones) are highlighted as research areas which deserve future attention. In addition, few studies have been conducted to determine the extent to which the biology of P. truncatus permits it to survive and reproduce in non-agricultural environments. These areas of study should be pursued as possible routes to providing more effective integrated pest managements strategies for the larger grain borer.     

Potential of sexual reproduction among host-adapted populations of Phytophthora infestans sensu lato in Ecuador

To determine the potential of sexual reproduction among host-adapted populations of Phytophthora infestans sensu lato in Ecuador, 13 A1 isolates belonging to clonal lineages US-1, EC-1 and EC-3, and 11 A2 isolates belonging to the clonal lineage EC-2, were paired on agar plates to induce crossing. In the first experiment, six A1 isolates (three US-1, two EC-1 and one EC-3) were each crossed with three A2 isolates (total = 18 crosses). Matings involving isolates of the EC-1 lineage produced more oospores of healthy appearance than did matings with isolates of US-1 or EC-3. In the second experiment, the oospores of 35 crosses (21 EC-1 × EC-2; 10 US-1 × EC-2; four EC-3 × EC-2) were dispersed on water agar to assess oospore germination. Overall, germination percentages were low. Only one cross produced enough progeny for evaluation. Twenty-three single-oospore offspring were isolated and evaluated for mating type; electrophoretic patterns of glucose-6-phosphate isomerase ( Gpi ) and peptidase ( Pep ) alloenzyme loci; mitochondrial DNA haplotype; and genomic DNA fingerprint. Multilocus genotype data indicated that all 23 isolates resulted from meiotic recombination. Four progeny with homothallic phenotype appeared to be unstable heterokaryons. Markers at several loci segregated according to simple Mendelian expectations for a diploid organism, but the ratios of three RFLP loci and the Pep locus were not consistent with Mendelian expectations. All progeny were nonpathogenic on hosts of the parental genotypes. Reduced mating success and reduced pathogenic fitness of progeny appear to be postmating mechanisms of reproductive isolation in populations of P. infestans sensu lato in Ecuador.     

Development and fecundity ofSitobion avenae on some wheat cultivars under laboratory conditions

Nymphal development time and fecundity ofSitobion avenae (F.) (Homoptera: Aphididae) were determined on nine widespread wheat varieties cultivated in Tekirdağ Region in Turkey. Tests were carried out in controlled environment chambers (25±1°C, 65±5% r.h.; 16:8, L:D). Development time (±S.E.) ranged from 5.75±0.25 to 7.20±0.20 days. Fecundity per female ofS. avenae was found to be the highest (12.87±1.50) on wheat cv. ‘Sana’. In this investigation cvs. ‘MV-17’, ‘Miryana’, ‘Pehlivan’ and ‘Saraybosna’ were particularly resistant againstS. avenae. http://www.phytoparasitica.org posting July 8, 2002.     

Resistance to Leveillula taurica in the genus Capsicum

One hundred and sixty-two Capsicum genotypes were evaluated for powdery mildew (Leveillula taurica) resistance, following inoculations with a suspension of 5 × 10⁴ conidia mL⁻¹ on 10-leaved to 12-leaved plants. Genotypes were graded into five resistance classes, based on the areas under the disease progress curves calculated from disease incidence (percentage infected leaves per plant) and severity (total number of colonies per plant). Results revealed a continuum from resistance to susceptibility, with the majority (70%) of C. annuum materials being classified as moderately to highly susceptible to L. taurica. Conversely, C. baccatum, C. chinense and C. frutescens were most often resistant, indicating that resistance to L. taurica among Capsicum species is found mainly outside the C. annuum taxon. Nevertheless, some resistant C. annuum material was identified that may be useful for resistance breeding. Eight genotypes were identified as immune to the pathogen: H-V-12 and 4638 (previously reported), and CNPH 36, 38, 50, 52, 279 and 288. Only H-V-12 and 4638 are C. annuum, while all others belong to the C. baccatum taxon. Latent period of disease on a set of commercial sweet pepper genotypes varied, indicating diverse levels of polygenic resistance. The latent period progressively reduced with plant maturity, from 14·3 days in plants at the mid-vegetative stage to 8·6 days in plants at the fruiting stage. Young plants of all commercial genotypes tested at the early vegetative stage were immune, irrespective of the reaction of the genotype at later stages, demonstrating widespread juvenile resistance to L. taurica in the Capsicum germplasm. Inoculation of plants of different botanical taxa with a local isolate indicated a wide host range. Some hosts, including tomato (Lycopersicon esculentum), artichoke (Cynara scolymus) and poinsettia (Euphorbia pulcherrima), produced large amounts of secondary inoculum. Other hosts included okra (Abelmoschus esculentus), eggplant (Solanum melongena), cucumber (Cucumis sativus), Solanum gilo, Chenopodium ambrosioides and Nicandra physaloides.     

新疆美洲斑潜蝇寄主种类及适合度的调查

通过乌鲁木齐、昌吉等地调查，发现新疆美洲斑潜蝇的寄主植物计有17科55种，其中蔬菜28种(变种)、大田作物8种，花卉和草坪植物13种、野生植物6种。以豆科、葫芦科植物受害最重。应用欧氏距离法的系统聚类分析，研究了美洲斑潜蝇对14种常见寄主植物的适合度；将其划分为5个类型，即最优适宜寄主、良好适宜寄主、适宜寄主、稍次适宜寄主和非适宜寄主。为害虫的防治决策提供了科学依据。