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41.
Pierre Hellin Maxime Duvivier Géraldine Dedeurwaerder Charlotte Bataille Michel De Proft Anne Legrève 《European journal of plant pathology / European Foundation for Plant Pathology》2018,151(4):1049-1064
With the aim of unravelling the role of airborne Fusarium graminearum inoculum in the epidemic of Fusarium head blight (FHB) caused by this species in wheat spikes, a network of Burkard air samplers was set up in five wheat fields distributed in Belgium from 2011 to 2013. Each year from April to July, the daily amounts of F. graminearum inoculum above the wheat canopy were quantified using a newly developed TaqMan qPCR assay. The pattern of spore trapping observed was drastically different per year and per location with a frequency of detection between 9 and 66% and a mean daily concentration between 0.8 and 10.2 conidia-equivalent/m3. In one location, air was sampled for a whole year. Inoculum was frequently detected from the wheat stem elongation stage until the end of the harvesting period, but high inoculum levels were also observed during the fall. Using a window-pane analysis, different periods of time around wheat flowering (varying in length and starting date) were investigated for their importance in the relation between airborne inoculum and FHB parameters (FHB severity, frequency of F. graminearum infection and DON). For almost all the combinations of variables, strong and significant correlations were found for multiple window lengths and starting times. Inoculum quantities trapped around flowering were highly correlated with F. graminearum infection (up to R?=?0.84) and DON (up to R?=?0.9). Frequencies of detection were also well correlated with both of these parameters. DON concentrations at harvest could even be significantly associated with the F. graminearum inoculum trapped during periods finishing before the beginning of the anthesis (R?=?0.77). Overall, these results highlight the key role of the airborne inoculum in F. graminearum epidemics and underline the importance of monitoring it for the development of disease forecasting tools. 相似文献
42.
Galina Lebedev Fauzi Abo‐Moch Guy Gafni David Ben‐Yakir Murad Ghanim 《Pest management science》2013,69(2):274-277
BACKGROUND: The onion thrips, Thrips tabaci Lindeman, is a major pest of several crop plants in the genus Allium, such as onions, garlic and chives. In Israel, these crops are grown in open fields and in protected housing. This thrips is usually controlled by the application of chemical insecticides. In recent years, spinosad, emamectin benzoate and carbosulfan have been the major insecticides used for the control of the onion thrips. In the last 4 years, growers of chives and green onion from several regions of Israel have reported a significant decrease in the efficacy of insecticides used to control the onion thrips. RESULTS: The susceptibility of 14 populations of the onion thrips, collected mainly from chives between the years 2007 and 2011, to spinosad, emamectin benzoate and carbosulfan was tested using a laboratory bioassay. The majority of the populations showed significant levels of resistance to at least one of the insecticides. LC50 values calculated for two of the studied populations showed that the resistance factor for spinosad compared with the susceptible population is 21 393, for carbosulfan 54 and for emamectin benzoate 36. Only two populations, collected from organic farms, were susceptible to the insecticides tested. CONCLUSION: This is the first report of a high resistance level to spinosad, the major insecticide used to control the onion thrips. Resistance cases to spinosad were associated with failures to control the pest. Populations resistant to spinosad also had partial or complete resistance to other insecticides used for controlling the onion thrips. Copyright © 2012 Society of Chemical Industry 相似文献
43.
Florian Chain Gérard Riault Maxime Trottet Emmanuel Jacquot 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(1):35-43
Serial passage experiments (SPE) of a Barley yellow dwarf virus-PAV (BYDV-PAV) isolate were performed on Zhong ZH and TC14 wheat lines to evaluate the durability of their resistance to BYDV. At different passage numbers (from the 2nd to the 114th), biological properties of the produced isolates were recorded either by monitoring infection percentages and virus titers of the first 3 weeks of viral infection or by measuring their impact on yield components. Statistical analyses using the area under pathogen progress curves and the area under concentration progress curves demonstrated that these two resistant lines induce, after only a few passages, a selection of variant(s) with significantly modified infection abilities. Isolates resulting from SPE performed on these lines induced important decreases of yield components. These results indicate that the use of Zhong ZH and TC14 lines in BYDV-resistant breeding programmes should be approached with caution. 相似文献
44.
Laboratory rearing of insects for scientific research ensures a constant supply of insects. However, laboratory colonies may
diverge genetically and/or phenotypically from wild populations due to selection pressures in their artificial environment.
This study examined how variation in a colony ofTrichoplusia ni influenced reproducibility over time of bioassays of toosendanin (a limonoid extracted from the bark ofMelia azedarach). In four of five experiments insect growth was reduced significantly (P=0.05) by the presence of toosendanin in the diet. The fifth experiment showed the same trend, but the effect was not significant.
Mean larval mass of both control and treated insects also varied greatly among experiments. The considerable variability observed
in this population highlights the importance of replicating experiments in time, and not just space, to confirm reproducibility
of treatment effects.
http://www.phytoparasitica.org posting Jan. 23, 2007. 相似文献
45.
Tsutomu MATSUMOTO Yuichiro NARA Hiromitsu FURUYA Harumi TAKAHASHI Kiichi TAIRAKO Hideki YAMAMOTO 《Journal of General Plant Pathology》2002,68(4):382-384
L11A-Fukushima (L11A-F) derived from attenuated isolate LuA of Tomato mosaic virus (ToMV) has the highest ability to cross protect against virulent ToMV among LuA and its derivatives and is stably inherited.
Growth, yield, fruit quality and symptom attenuation of inoculated tomato plants did not differ significantly between L11A-F and L11A. The infectivity of progeny viruses in tomato infected with LuA-F was less than 4% of that with virulent ToMV. From these
results, L11A-F appears to possess the properties necessary for practical use. To manage L11A-F strictly, a PCR-based assay to detect trace contamination of virulent ToMV in L11A-F preparations was established.
Received 10 June 2002/ Accepted in revised form 30 October 2002 相似文献
46.
Land use changes operate at different scales. They trigger a cascade of effects that simultaneously modify the composition
or structure of the landscape and of the local vegetation. Mobil animals, and birds in particular, can respond quickly to
such multi-scalar changes. We took advantage of a long term study on the response of songbirds to land-use changes on four
Mediterranean islands in Corsica and Sardinia to explore the benefits of a multi-scale analysis of the relationships between
songbird distribution, vegetation structure and landscape dynamics. Field data and aerial photographs were used to describe
the vegetation at three different scales. Birds were censused by point counts. We used statistical variance decomposition
to study how bird distribution and vegetation at various scales were linked. We analysed multi-scale vegetation changes (floristic
composition, plot vegetation type, and landscape structure) and their consequences on bird distribution with multivariate
and non-parametrical tests. The distribution of most species was linked to at least two spatial scales. The weight of a given
scale was consistent with life-history traits for species whose biology was well-known. In the examples studied, vegetation
composition, vegetation type and landscape changes that resulted from land abandonment negatively affected birds depending
on open or heterogeneous areas. Our results emphasize that multi-scale analyses can greatly enhance our understanding of bird
distribution and of their changes. Management of these populations should take into account measures at various spatial scales
depending on the sensitivity of the species. 相似文献
47.
Heike Kappes Kurt Jordaens Frederik Hendrickx Jean-Pierre Maelfait Luc Lens Thierry Backeljau 《Landscape Ecology》2009,24(5):685-697
Habitat fragmentation is a major cause for species loss, but its effect on invertebrates with low active dispersal power,
like terrestrial gastropods, has rarely been studied. Such species can not cross a hostile habitat matrix, for which the predictions
of island theory, such as positive relations between species richness and patch size, should apply. In order to test this
prediction, we studied gastropod species diversity by assessing gastropod assemblage characteristics from 35 sites in 19 fragments
of deciduous old-growth forests in the Lower Rhine Embayment, Germany. Assemblages differed between larger (≥700 ha) and smaller
forests (<400 ha), those of large forests held a higher percentage of forest species. Although α-diversity was similar between
the two forest size classes, small forests often comprised matrix species, resulting in a higher β-diversity. Edge effects
on the species richness of matrix species were noticeable up to 250 m into the forest. Hierarchical partitioning revealed
that distance to disturbances (external edge, internal edges like roads) explained most assemblage variables, whereas forest
size and woodland cover within a 1 km radius from the sites explained only a few assemblage variables. Densities of two forest-associated
species, Discus rotundatus and Arion fuscus, decreased with forest size. Yet, forest size was positively correlated with richness of typical forest species and densities
of Limax cinereoniger. The latter species seems to need forests of >1,000 ha, i.e., well above the size of most fragments. In conclusion, the prediction
is valid only for forest species. The response to fragmentation is species specific and seems to depend on habitat specialization
and macroclimatic conditions.
Jean-Pierre Maelfait: Deceased. 相似文献
48.
Christopher R. Thornton 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(3):347-353
Species of the genus Trichoderma are ubiquitous soil-borne fungi that exhibit antagonism towards a number of economically important plant-pathogenic fungi
and oomycetes. This review discusses recent developments in the use of monoclonal antibodies to detect these fungi in their
natural soil environments and to quantify their population dynamics during antagonistic interactions with saprotrophic competitors
in soil-based systems. Immunological approaches to detection and quantification are examined in relation to conventional plate
enrichment techniques and to nucleic acid-based procedures. An example of recent research using a mAb-based assay to quantify
the effects of saprotrophic competition on the growth of Trichoderma isolates in mixed species, soil-based, microcosms is presented. Future technological developments in immunoassays for tracking
Trichoderma populations in soil are discussed and results presented showing the accurate detection and visualization of a plant growth-promoting
isolate of T. hamatum in the rhizosphere of lettuce using mAb-based immunodiagnostic assays. 相似文献
49.
50.
家蚕微孢子虫感染家蚕对其中肠和血液蛋白酶活性影响 总被引:1,自引:0,他引:1
本试验测定了不同浓度剂量微孢子虫感染家蚕后,家蚕中肠和血液中蛋白酶的变化.并对不同浓度剂量家蚕微孢子虫感染家蚕后对家蚕发育的影响和不同组织中所含微孢子虫孢子的浓度等作了初步的研究.从本实验中可以看出,感染不同浓度微孢子虫的家蚕,体内相同组织的微孢子虫数量存在显著差异.而感染相同浓度微孢子虫的蚕,不同组织中微孢子虫的数量也有差异,中肠的微孢子虫数量远高于其他部位.感染微孢子虫后,家蚕血液中的蛋白酶活性显著升高,中肠的蛋白酶的活性变化不显著,而感染微孢子虫的数量对血液和中肠中的蛋白酶的活性无显著影响. 相似文献