Effect of temperature,hydrogen ion concentration and osmotic potential on oospore germination of fivePythium spp. isolated from pond water

Oospore germination occurred over a temperature ranging of 15–35°C forPythium coloratum, 10–35°C forP. diclinum, 15–30°C forP. dissotocum, 7–30°C forP. monospermum, and 10–30°C forP. pleroticum. Optimum temperature was 25°C for all species tested. In case of pH, oospore germination occurred over a range of 4.76–8.55 with an optimum of 6.40–7.40. The least germination occurred at pH 4.76 forP. coloratum, P. diclinum, P. monospermum andP. pleroticum, whileP. dissotocum germinated from pH 5.02. Oospores of the all tested pythia were able to germinate at –0.13 to –1.65 MPa and could not germinate at –3.40 MPa, with the highest germination rate at –0.27 to –0.47 MPa. The effect of temperature, pH and osmotic potential on oospore germination was discussed in relation to pollution of pond water.     

Species of Bursaphelenchus Fuchs, 1937 (Nematoda: Parasitaphelenchidae) and other nematode genera associated with insects from Pinus pinaster in Portugal

Insects associated with maritime pine, Pinus pinaster, in Portugal were collected and screened for the presence of Bursaphelenchus species. Nematodes were identified using Internal Transcribed Spacers‐Restriction Fragment Length Polymorphism (ITS‐RFLP) analysis of dauer juveniles and morphological identification of adults that developed from dauer juveniles on fungal cultures or on cultures in pine wood segments at 26°C. Several associations are described: Bursaphelenchus teratospicularis and Bursaphelenchus sexdentati are associated with Orthotomicus erosus; Bursaphelenchus tusciae, B. sexdentati and/or Bursaphelenchus pinophilus with Hylurgus ligniperda and Bursaphelenchus hellenicus with Tomicus piniperda, Ips sexdentatus and H. ligniperda. An unidentified Bursaphelenchus species is vectored by Hylobius sp. The previously reported association of Bursaphelenchus xylophilus with Monochamus galloprovincialis was confirmed. The association of Bursaphelenchus leoni with Pityogenes sp. is not definitively established and needs further studies for clarification. Other nematode genera besides Bursaphelenchus were found to be associated with the insects sampled, including two different species of Ektaphelenchus, Parasitorhabditis sp., Parasitaphelenchus sp., Contortylenchus sp. and other unidentified nematodes. The Ektaphelenchus species found in O. erosus is morphologically similar to B. teratospicularis found in the same insect; adults of both the species are found in cocoon‐like structures under the elytra of the insects.     

Comparison of trap designs for use with aggregation pheromone and synthetic co-attractant in a user-friendly attract and kill system to control Carpophilus spp. (Coleoptera: Nitidulidae)

Abstract  Three field experiments were conducted in stone fruit orchards in the Goulburn Valley, northern Victoria, Australia to identify a user-friendly trap for use in attract and kill stations for control of Carpophilus spp. (Coleoptera: Nitidulidae). A funnel trap design was compared with two types of delta trap in one experiment and two types of Lucitrap in another experiment. All traps were baited with synthetic co-attractant and synthetic pheromone. The funnel trap was the most effective type of trap tested. The funnel traps caught significantly more beetles than either the delta traps with bio-attractant or delta traps wrapped with insecticide impregnated banana wrap. No difference was observed between catches in either delta trap design. Lucitraps without covers caught significantly more beetles than Lucitraps with covers but funnel traps caught significantly more beetles than either type of Lucitrap. Beetle numbers caught in the funnel traps were three to five times higher than in Lucitrap. The use of funnel traps in attract and kill stations to protect stone fruit crops by suppressing the Carpophilus spp. population gave superior control to 'grower normal practice of spraying insecticides' both in terms of Carpophilus spp. numbers and in terms of reduction in percentage of fruit damaged.     

田间条件下甘蔗品种对蛀茎夜蛾的抗性评价

[目的]蛀茎夜蛾Sesamia spp.是伊朗和其他国家(包括印度、巴基斯坦、斯里兰卡和日本)甘蔗上最具破坏性的害虫.蛀茎夜蛾幼虫钻蛀茎秆,对茎秆产生为害,降低重量和含糖量并降低甘蔗汁品质.应用抗性品种是一种有效的工具,对环境无不利影响.本研究旨在评价甘蔗商业品种对蛀茎夜蛾的抗性.[方法]在伊朗Ahwaz的Salman-Farsi Ago-industry Farms于2013-2014和2014-2015两个连续年份,采用随机区组设计进行5次重复试验.应用了CP69-1062,CP48-103,CP57-614,CP73-21,SP70-1143,IRC99-01,IRC99-02和L62-96 8个品种.在收获前,随机取20株完整的甘蔗茎秆进行蛀茎夜蛾的为害评估.记录受害茎秆百分比、被钻蛀的节间百分比(percent ofinternodes bored,IB)、出口孔的数目、活的蛀茎夜蛾的数目、每品种每公顷面积中蛾的繁殖量(mothproduction per hectare of each variety,MP).[结果]各测定参数在品种间均存在显著差异.从被钻蛀的节间百分比和蛾的繁殖指数判断,L62-96是最敏感的品种(2014年:14.58％ IB,95 200 MP/ha;2015年:16.76％ IB和111 300 MP/ha),其次是CP69-1062和CP48-103;CP57-614是这两年中抗性最强的品种(2014年:1.24％ IB,8 400 MP/ha;2015年:1.02％ IB,7 000 MP/ha).[结论]建议限制敏感品种的栽培,并应用其他控制措施,结合品种抗性,以治理敏感品种中的蛀茎夜蛾.     

Analysis of the sodium chloride‐dependent respiratory kinetics of wheat mitochondria reveals differential effects on phosphorylating and non‐phosphorylating electron transport pathways

A number of previous studies have documented the gross response of mitochondrial respiration to salinity treatment, but it is unclear how NaCl directly affects the kinetics of plant phosphorylating and non‐phosphorylating electron transport pathways. This study investigates the direct effects of NaCl upon different respiratory pathways in wheat, by measuring rates of isolated mitochondrial oxygen consumption across different substrate oxidation pathways in saline media. We also profile the abundance of respiratory proteins by using targeted selected reaction monitoring (SRM) mass spectrometry of mitochondria isolated from control and salt‐treated wheat plants. We show that all pathways of electron transport were inhibited by NaCl concentrations above 400 mM; however electron transfer chains showed divergent responses to NaCl concentrations between 0 and 200 mM. Stimulation of oxygen consumption was measured in response to NaCl in scenarios where exogenous NADH was provided as substrate and electron flow was coupled to the generation of a proton gradient across the inner membrane. Protein abundance measurements show that several enzymes with activities less affected by NaCl are induced by salinity, whereas enzymes with activities inhibited by NaCl are depleted. These data deepen our understanding of how plant respiration responds to NaCl, offering new mechanistic explanations for the divergent salinity responses of whole‐plant respiratory rate in the literature.     

Causes and consequences of large clonal assemblies in a poplar hybrid zone

Asexual reproduction is a common and fundamental mode of reproduction in plants. Although persistence in adverse conditions underlies most known cases of clonal dominance, proximal genetic drivers remain unclear, in particular for populations dominated by a few large clones. In this study, we studied a clonal population of the riparian tree Populus alba in the Douro river basin (northwestern Iberian Peninsula) where it hybridizes with Populus tremula, a species that grows in highly contrasted ecological conditions. We used 73 nuclear microsatellites to test whether genomic background (species ancestry) is a relevant cause of clonal success, and to assess the evolutionary consequences of clonal dominance by a few genets. Additional genotyping‐by‐sequencing data were produced to estimate the age of the largest clones. We found that a few ancient (over a few thousand years old) and widespread genets dominate the population, both in terms of clone size and number of sexual offspring produced. Interestingly, large clones possessed two genomic regions introgressed from P. tremula, which may have favoured their spread under stressful environmental conditions. At the population level, the spread of large genets was accompanied by an overall ancient (>0.1 Myr) but soft decline of effective population size. Despite this decrease, and the high clonality and dominance of sexual reproduction by large clones, the Douro hybrid zone still displays considerable genetic diversity and low inbreeding. This suggests that even in extreme cases as in the Douro, asexual and sexual dominance of a few large, geographically extended individuals does not threaten population survival.     

Amendment with biocontrol strains increases Trichoderma numbers in mature kiwifruit (Actinidia chinensis) orchard soils for up to six months after application

A Trichoderma mixture was applied to kiwifruit plants in a pot experiment and to mature orchard vines to determine its effect on numbers of root-associated fungi and compare application methods into kiwifruit orchards in New Zealand. Trichoderma and other fungal numbers were recorded using a root plating technique. In the pot experiment, a significantly greater number of Trichoderma was isolated from treated compared to untreated plants 6 and 10 weeks after inoculation. Six months after application, greater numbers of Trichoderma were recovered in the orchards from Trichoderma treated vines and the increase was comparable for all application methods with over 50% of isolated fungi identified as Trichoderma compared to 33% in the water-only control. Different viable methods are available that can easily be integrated into everyday orchard management in order to introduce Trichoderma into mature kiwifruit stands. A six-monthly or more frequent application schedule seems advisable.     

Species distribution,virulence factors and antimicrobial resistance of Acinetobacter spp. isolates from dogs and cats: a preliminary study

In this study, the prevalence of virulence factors and antimicrobial resistance among 67 Acinetobacter spp. isolates, consisting of 21 Acinetobacter baumannii and 46 non‐baumannii Acinetobacter obtained from companion animals, was investigated. PCR analysis showed that the most prevalent virulence gene was afa/draBC (29.9%), followed by papC (22.4%) and cvaC (20.9%). Antimicrobial susceptibility testing revealed that resistance to gentamicin (14.9%) and ciprofloxacin (11.9%) was relatively prevalent. Five gentamicin‐ and/or ciprofloxacin‐resistant A. baumannii strains were assigned to ST25, ST149, ST164, ST203 and ST1198. All ciprofloxacin‐resistant isolates harbored point mutations in gyrA and/or parC. To the best of our knowledge, this is the first report of preliminary monitoring of animal‐origin Acinetobacter spp. in Japan.

     

Factors influencing the occurrence of males in natural populations of Synchaeta spp.

Changes in the temporal abundance of females and males of Synchaeta spp. were followed for one year (1983) at two stations in the brackish northern Baltic proper. Males were found only when the abundance of females was increasing and the phytoplankton biomass was dominated by large diatoms.     

Distribution of Field Corn Roots and Parasitic Nematodes in Subsoiled and Nonsubsoiled Soil

A field trial was conducted for 2 years in an Arredondo fine sand containing a tillage pan at 15-20 cm deep to determine the influence of subsoiling on the distribution of corn roots and plant-parasitic nematodes. Soil samples were taken at various depths and row positions at 30, 60, and 90 days after planting in field corn subsoiled under the row with two chisels and in non-subsoiled corn. At 30 and 60 days, in-row nematode population densities to 60 cm deep were not affected by subsoiling compared with population densities in nonsubsoiled plots. After 90 days, subsoiling had not affected total root length or root weight at the 20 depth-row position sampling combinations, but population densities of Meloidogyne incognita and Criconemella spp. had increased in subsoiled corn. Numbers of Pratylenchus zeae were not affected. Subsoiling generally resulted in a change in distribution of corn roots and nematodes in the soil profile but caused little total increase in either roots or numbers of nematodes. Corn yield was increased by subsoiling.