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1.
The effect of spraying winter rape and winter wheat with deltamethrin on the numbers of epigeal Carabidae, Staphylinidae and Linyphiidae caught in pitfall traps was studied in Northern Germany in 1980 and 1981. Two experiments were performed with each crop, deltamethrin being sprayed at 7.5 g a.i. ha?1 in 300 litres of water in springtime on rape, and in midsummer on wheat. Sprayed plots were rectangles of 2 and 3 ha; unsprayed plots were squares of 0.5 ha each (two replicates). Ten pitfall traps were placed per replicate at least 3 weeks before spraying and were left for at least 3 weeks after spraying, the traps being emptied weekly. Beneficial Carabid species which have been shown already to have an economic significance, were rare during this study, but four other species (three of them were autumn breeders) were not affected by deltamethrin. At the spraying dates the autumn breeders were hidden in the soil as pupae. Three Staphylinid species, studied in only one experiment each, appeared to be strongly reduced in numbers by deltamethrin. The Linyphiid spiders were affected most heavily by deltamethrin sprayed in spring or in midsummer; the initial mortality of more than 92% lasted longer than 4 weeks, and an adverse effect was still significant in winter wheat 6 weeks after spraying. Overall, deltamethrin appears to have a broad spectrum effect concerning the epigeal predatory arthropods. 相似文献
2.
Inge M Krijger Steven R Belmain Grant R Singleton Peter WG Groot Koerkamp Bastiaan G Meerburg 《Pest management science》2017,73(12):2397-2402
Current reactive pest management methods have serious drawbacks such as the heavy reliance on chemicals, emerging genetic rodenticide resistance and high secondary exposure risks. Rodent control needs to be based on pest species ecology and ethology to facilitate the development of ecologically based rodent management (EBRM). An important aspect of EBRM is a strong understanding of rodent pest species ecology, behaviour and spatiotemporal factors. Gaining insight into the behaviour of pest species is a key aspect of EBRM. The landscape of fear (LOF) is a mapping of the spatial variation in the foraging cost arising from the risk of predation, and reflects the levels of fear a prey species perceives at different locations within its home range. In practice, the LOF maps habitat use as a result of perceived fear, which shows where bait or traps are most likely to be encountered and used by rodents. Several studies have linked perceived predation risk of foraging animals with quitting‐harvest rates or giving‐up densities (GUDs). GUDs have been used to reflect foraging behaviour strategies of predator avoidance, but to our knowledge very few papers have directly used GUDs in relation to pest management strategies. An opportunity for rodent control strategies lies in the integration of the LOF of rodents in EBRM methodologies. Rodent management could be more efficient and effective by concentrating on those areas where rodents perceive the least levels of predation risk. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. 相似文献
3.
Roots from healthy and diseased mature ponderosa pine, Pinus ponderosa Laws., trees were excavated from a site near Burns, Oregon. The diseased trees were infected with black-stain root disease, Leptographium wageneri Kendrick, or annosus root disease, Heterobasidion annosum (Fr.) Bref., or both. Axial hydraulic conductivity of the roots was measured under a positive head pressure of 5 kPa, and the conducting area was stained with safranin dye to determine specific conductivity (k(s)). In diseased roots, only 8-12% of the cross-sectional xylem area conducted water. Resin-soaked xylem completely restricted water transport and accounted for 13-16% of the loss in conducting area. In roots with black-stain root disease, 17% of the loss in conducting area was associated with unstained xylem, possibly resulting from occlusions or embolisms. Based on the entire cross-sectional area of infected roots, the k(s) of roots infected with black-stain root disease was 4.6% of that for healthy roots, whereas the k(s) of roots infected with annosus root disease was 2.6% of that for healthy roots. Although these low values were partly the result of the presence of a large number of diseased roots (72%) with no conducting xylem, the k(s) of functional xylem of diseased roots was only 33% of that for healthy roots. The low k(s) values of functional xylem in diseased roots may be caused by fungus induced occlusions preceding cavitation and embolism of tracheids. The k(s) of disease-free roots from diseased trees was only 70% of that for healthy roots from healthy trees. The disease-free roots had the same mean tracheid diameter and tissue density as the healthy roots, suggesting that the lower k(s) in disease-free roots of diseased trees may also have been caused by partial xylary occlusions. 相似文献
4.
[德]史达 《湖南农业大学学报(自然科学版)》2014,(4):7-10
岳麓秦简《为狱等状四种》新见的一枚漏简解析了案例六《暨过误失坐官案》的结构。这个案例中的“八劾”含有对其的两遍描述:第一遍比较具体的;第二遍比较简略的。新见简J15位于案例六的开头,包含对第一、二劾的具体描述。因此,整理者原来所建议的简序应当稍微修正为:J15-缺简-096-097-095-098-099-100。 相似文献
5.
Published studies of rhizobial populations, communities and other strain collections were analysed to identify trends in strain richness, strain dominance and genetic diversity within and between locations. For individual populations and communities, strain richness indices were calculated by dividing the number of strain types identified by the number of isolates recovered. Where possible, strain dominance (the proportion of rhizobial isolates represented by each strain type) was also calculated. Analysis of the genetic diversity of populations, communities and rhizobial strain collections originating from diverse legume hosts and locations, was confined to studies using multilocus enzyme electrophoresis (MLEE) so that diversity could be compared on the basis of published H values. Strain richness indices were highly variable (0.02-0.94) and were influenced by both the discriminatory power of the strain typing method and the type and number of legume species used to recover rhizobia from soil. The strain richness of populations recovered either directly from soil, or from the nodules of trap hosts inoculated with the same soil, was similar. Because the arithmetic relationship between the number of strain types and number of isolates varies between different populations and communities, strain richness curves are proposed as the most appropriate method for reporting rhizobial structural diversity. Comparison of over 50 rhizobial populations and communities from published studies showed that strain dominance patterns in nodules were often similar. Typically, a single strain type occupies more than 30% of nodules with the majority of strain types being recovered at low frequency (∼75% of published populations and communities). Rhizobial populations and communities characterised by MLEE varied in their genetic diversity, with H values ranging from 0.06 to 0.78. In several studies, most of the genetic diversity within a site could be recovered from the nodules of a single plant. When hierarchical analyses were performed on populations within and between sites, the genetic diversity within sites was similar to the genetic diversity between sites. Similarly, the genetic diversity of strain collections originating from multiple hosts and locations was no more diverse than some individual populations and communities. Strain richness and genetic diversity measures were not always correlated for rhizobial populations. Populations with low strain richness were sometimes genetically diverse, and the relationship between the diversity measures varied for different legume species at the same location. We suggest that both strain richness and genetic diversity measures are required to fully describe rhizobial population and community diversity. 相似文献
6.
Relationships between Acid Ions and Carbonaceous Fly-Ash Particles in Deposition at European Mountain Lakes 总被引:1,自引:0,他引:1
N.L. Rose E. Shilland T. Berg K. Hanselmann R. Harriman K. Koinig U. Nickus B. Steiner Trad E. Stuchlík H. Thies M. Ventura 《Water, air, and soil pollution》2001,130(1-4):1703-1708
The concentrations of major ions and spheroidal carbonaceous fly-ash particles (SCPs) in bulk deposition were determined in weekly samples from six European mountain lakes during 1997/98. SCPs are produced only from high temperature combustion of fossil-fuels and therefore provide an unambiguous indicator of atmospheric deposition from this source. Positive correlations were observed between SCPs and SO4 2?, NO3 ? and NH4 + at all sites except for some determinands at Jorisee (Switzerland) and Starolesnienske (Slovakia). Correlations between SCPs and SO4 2? + NO3 ? were always more positive than for SCPs with 'total acid ions' (SO4 2? + NO3 ? + NH4 +). This is in agreement with the expectation that the contribution to NH4 + deposition made by fossil-fuels is negligible. Good positive correlations between SCPs and all acid anions were observed at Estany Redo (Pyrenees); lower but still positive correlations were observed for all acid ions with SCPs at Gossenköllesee (Austria), Lochnagar and Kårvatn (central Norway), whilst little trend in correlation was observed for Jorisee and Starolesnienske. It is suggested that this gradient reflects the influence of fossil-fuels on acid deposition in these areas. A high positive correlation was observed between SCP and Cl? at Gossenkollesee possibly as a result of HCl from coal combustion. 相似文献
7.
Amnon?LeviEmail author Claude?E.?Thomas Alvin?M.?Simmons Judy?A.?Thies 《Genetic Resources and Crop Evolution》2005,52(4):465-472
A cucurbit species named Praecitrullus fistulosus (Stocks) Pangalo, which thrives in India, is considered to be a distant
relative of watermelon. Recent experiments indicated that it has mild resistance to whiteflies (Bemisia tabaci). However,
our attempts to cross various US plant introductions (PIs) of P. fistulosus with watermelon or other Citrullus PIs have not
been successful. Thus, to determine genetic relatedness among those species, phylogenetic analysis [based on simple sequence
repeat (SSR)–anchored (also termed ISSR), and randomly amplified polymorphic DNA (RAPD) markers] was conducted among PIs of
P. fistulosus, Citrullus lanatus var. lanatus (watermelon), C. lanatus var. citroides and the wild Citrullus colocynthis.
Phylogenetic relationships were also examined with Cucumis melo (melon), Cucumis sativus (cucumber), and wild Cucumis species
including C. africanus, C. metuliferus, C. anguria, C. meeusei, and C. zeyheri. Wide genetic distance exists between Citrullus
and Cucumis groups (8% genetic similarity). Phylogenetic relationships among Citrullus species and subspecies are closer (25–55%
genetic similarity) as compared with those among most Cucumis species (14–68% genetic similarity). P. fistulosus appeared
to be distant from both Cucumis and Citrullus species (genetic similarity between P. fistulosus and Cucumis or Citrullus groups
is less than 3%). Although wide genetic differences and reproductive barriers exist among cucurbit species examined in this
study, they are still considered as potential germplasm source for enhancing watermelon and melon crops using traditional
breeding and biotechnology procedures. 相似文献
8.
I Kuzmenko R Buller WG Bouwman K Kjaer J Als-Nielsen M Lahav L Leiserowitz 《Science (New York, N.Y.)》1996,274(5295):2046-2049
Thin interdigitated films composed of a long-chain, water-insoluble chiral acid (p-pentadecylmandelic acid of absolute configuration R) and a water-soluble chiral base (phenylethylamine, R') were constructed at the air-solution interface. The (R, R') structure was characterized to near-atomic resolution by grazing-incidence x-ray diffraction (GIXD). The two diastereomeric systems, (R, R') and (R, S'), demonstrate similar surface pressure-molecular area isotherms, but their structures are completely different on the molecular level, as monitored by GIXD. Complementary data on these two architectures were provided by atomic force microscopy. 相似文献
9.
10.
Weixiang Wu Haohao Lu Wei Liu Medha Devare Janice E. Thies Yingxu Chen 《Journal of Soils and Sediments》2009,9(5):457-467