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Virulence and efficacy of five species and strains of the entomopathogenic nematodes of the families Steinernematidae and Heterorhabditidae:Steinernema riobravis, Steinernema feltiae strains Ger. and UK, andHeterorhabditis bacteriophora strains HP88 and IS5, against the prepupal and pupal stages of the western flower thrips (WFT),Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), were investigated in the laboratory. Although all these nematodes controlled WFT to some extent, they differed in efficiency. The heterorhabditid nematodeH. bacteriophora strain HP88 was more specific to the soil-inhabiting WFT stages (36–49% thrips mortality). The steinernematid nematodesS. riobravis andS. feltiae strains Ger. and UK had only a slight effect (10% mortality) on prepupal and pupal populations of WFT, andH. bacteriophora strain IS5 had the least effect of all. A possible reason for such species variation is suggested and discussed. 相似文献
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Flowers of 22 plant species grown in the Arava region of Israel were sampled at periodic intervals to study the seasonal abundance
ofFrankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Samples were collected from the most common cut-flower and vegetable plant species
in this area during 1997 and from pepper in 1996–1998. Western flower thrips (WFT) was detected on 19 of the plant species
surveyed, and it reproduced on numerous plant species. WFT counts peaked in late February–April and in October–December. The
peak density of WFT during March in our survey corresponded to the peak flowering of cut-flower plants (during spring) and
sweet pepper (during autumn). Thrips population was less abundant during autumn than in spring and was very low during summer.
The possible reasons for fluctuations in thrips densities are abiotic factors (temperature and relative humidity), and availability
of flowering plants. The high temperature (>40°C) and low humidity (∼20%) in summer caused a drastic reduction in WFT populations,
although some flowering plant species were available in this season. WFT population remained low until October, when adults
appeared in large numbers on flowering pepper. We assume that the thrips had survived the hottest months by aestivation and
migrated to the plants when air temperature decreased. In most samples from the cut-flower fields, 84.8% were adult WFT; only
during the period from the end of January to March, did the proportion of immature stages in the thrips population increase
to 31.6%. Females always outnumbered males (71% females). In pepper fields during the first cropping month the thrips population
included 96% adults; from November onwards, the proportions of adults and immatures were almost equal; and females outnumbered
males. Organic pepper fields were not infested with thrips because of the presence of the predatory bugOrius albidipennis (Fieber).
Contribution from the Agricultural Research Organization. No. 534/00, 2000 series.
http://www.phytoparasitica.org posting July 16, 2002. 相似文献
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Vladimir Shanin Alexander Komarov Raisa Mäkipää 《European Journal of Forest Research》2014,133(2):273-286
The objective was to analyse how differences in the initial proportions of tree species and site fertility affect carbon sequestration in living biomass and soil. We used the individual-based simulation model EFIMOD, which is able to simulate spatially explicit competition between trees for light and nutrients. Simulations were carried out for three site types with distinct initial stocks of soil nutrients. For each site, the 100-years undisturbed dynamics of monocultures and mixtures of three tree species (Betula pendula Roth, Pinus sylvestris L. and Picea abies (L.) H. Karst.) was predicted. Changes in the proportions of competing tree species were dependent on the fertility of the site: on poor sites, pine was the most competent species, while on rich sites, spruce increased its proportion during stand succession. Net primary production (NPP) and soil respiration were the highest in stands of two coniferous species and in stands with a high initial proportion of pine. Mixed stands were more productive than monocultures; the highest overyielding was observed with mixtures of two coniferous species. Simulated NPP and carbon stocks in all pools increased from poor to rich sites. The highest carbon stocks in standing biomass were observed for mixtures of conifer species and three-species mixtures; the greatest accumulation of forest floor occurred in stands with high proportions of pine. 相似文献
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Tapio Linkosalo Hanna el-Khouri Raisa Mäkipää Pertti Pulkkinen Eija Juurola 《Scandinavian Journal of Forest Research》2017,32(8):651-657
We conducted an experiment to find out how future climate conditions will impact the spring development of photosynthetic capacity of silver birch leaves. We had two greenhouse conditions. In the simulated future climate condition, we had both elevated temperatures and CO2 concentration, while for reference we had trees growing under current climate conditions. We used two methods to measure the development of photosynthetic capacity: first, the maximum quantum efficiency of photosystem II with a fluorescence meter; and second, the CO2 assimilation rate with gas exchange measurements. The development of full photosynthetic capacity took around two weeks following the bud burst. The maximum quantum efficiency developed slightly faster than the CO2 assimilation rate. Both measurement methods showed that an elevated CO2 concentration enhanced the development of photosynthetic capacity beyond the impact of temperature only. The enhancement under the conditions of our simulated climate change translates to achieving photosynthetic capacity up to five days earlier, which impact should be taken into account in simulations of photosynthetic productivity. 相似文献
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Uncertainty estimation of biomass expansion factors for Norway spruce in the Czech Republic 总被引：1，自引：0，他引：1
Aleksi Lehtonen Emil Cienciala Fedor Tatarinov Raisa Mäkipää 《Annals of Forest Science》2007,64(2):133-140
Nation wide estimates of the changes in forest biomass are needed for the greenhouse gas (GHG) reporting under the Climate Convention. The bases for national GHG reporting concerning forest sector are the national forest inventory (NFI) programmes. Since these programmes were mostly established for monitoring of timber resources, one of the current challenges for the NFIs is the development of methodology, such as biomass expansion factors (BEFs). The methodology for carbon stock change estimation should be transparent and verifiable, but this demand is not currently met due to the fact that the source data and uncertainty in the applied BEFs are not known. Here we developed BEFs with uncertainty estimation applicable to stand wise inventory of Norway spruce forests in the Czech Republic. BEFs were constructed, based on tree wise data from permanent research plots, by applying biomass and volume models to tree-level data. These BEFs were age-dependent and their uncertainty was sensitive to the dependencies among errors. Most of the uncertainty in the BEFs was due to uncertainty in the biomass and volume models applied. 相似文献
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Bianca Mayumi Silva Kida Raisa Pereira Abdalla Renata Guimarães Moreira 《Fish physiology and biochemistry》2016,42(5):1347-1356
Metals can influence the gonadal steroidogenesis and endocrine systems of fish, thereby affecting their reproduction. The effects of aluminum and manganese in acidic water were investigated on steroidogenesis in sexually mature male Astyanax altiparanae. Whether mature male fish recover from the effects of metals in metal-free water was also assessed. The fish were exposed to 0.5 mg L?1 of isolated or combined aluminum and manganese in acidic pH (5.5) to keep the metals bioavailable. The fish underwent 96 h of acute exposure, and samples were taken 24 and 96 h after the beginning of the experiment. The fish were then maintained in metal-free water for 96 h. Plasma levels of testosterone, 11-ketotestosterone, 17β-estradiol, and cortisol were measured. Acidic water increased the plasma concentration of testosterone and 11-ketotestosterone. Aluminum increased the testosterone levels after 96 h of exposure. Manganese increased the 17β-estradiol levels after 24 h of exposure and maintained at high levels until the end of the experiment. With the exception of acidic pH, which increased cortisol levels after 24 h of exposure, no changes were observed in this corticosteroid during the acute experiment. Aluminum and manganese together also altered steroid levels but without a standard variation. The fish recovered from the effects of most exposure conditions after 96 h in metal-free water. A. altiparanae could use reproductive tactics to trigger changes in testicular steroidogenesis by accelerating spermatogenesis and spermiogenesis, which may interfere with their reproductive dynamics. 相似文献
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M. Wysoki M. Wysoki M. Klein M. Davidovich R. Shaked K. Rosenfeld E. Pressman Phyllis G. Weintraub A. R. Horowitz Sophia Kleitman R. Azari Leah Tsror A. R. Horowitz Phyllis G. Weintraub Svetlana Kontsedalov I. Ishaaya Raisa Chyzik M. Klein Orna Ucko S. Steinberg M. Coll D. Rosen D. Gouldman S. Steinberg Ayala Lalouche S. Steinberg M. Coll D. Ben-Yakir M. Chen Y. Antignus Y. Messika N. Dudai A. Gera Anat Kritzman J. Cohen B. Raccah 《Phytoparasitica》1999,27(3):243-250
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In 1992 and 1993, sunflower (Helianthus annuus L.) crops in Israel were heavily damaged by the western flower thrips (WFT),Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Adult females appear in the heads of sunflower just as the latter begin to blossom;
the population decreases towards completion of anthesis. The damage to kernels is greatest at the periphery of the heads,
where flowers appear first, and lowest at the center. Fields sown early in the season (in March) are usually the ones infested
most by WFT and suffering the greatest damage. Fields sown one month later are less infested, since predatory bugs of the
genusOrius are very active at that time. 相似文献