Soybean stem fly,Melanagromyza sojae (Diptera: Agromyzidae), on Sumatra: Seasonal incidence and the role of parasitism     

H. Van Den Berg  D. Ankasah  K. Hassan  A. Muhammad  H. A. Widayanto  H. B. Wirasto 《国际虫害防治杂志》2013,59(3):127-133

Abstract

The density of M. sojae and percentage parasitism was studied in unsprayed soybean at 18 farmers’ field sites in Aceh, North Sumatra and West Sumatra provinces, Indonesia, during 1992 and 1993. M. sojae generally infested soybean throughout the season; infestation was initially low, reached its peak from the fifth till the eighth week after planting and declined towards the end of the season. A complex of seven hymenopterous parasiloids had a high impact on the pest. Parasitism levels built up alongside with host density and remained high until just before harvest. The eucoilid Gronotoma sp. was the most prevalent species during the early and mid‐season; a complex of pteromalids became dominant towards the end of the season. In soybean planted successively at 2‐week intervals, the parasitism level in the first‐planted crop built up slowly, whereas the parasitism level in the third‐planted crop was high from the early crop stage onwards, which suggests that the third‐planted crop benefited from parasitism build‐up in the earlier‐planted crops. The role of parasitoids in controlling beanflies in unsprayed soybean is discussed.  相似文献   

On-farm evaluation of measures to monitor and control soybean pod-borer Etiella zinckenella in East Java,Indonesia     

H. Van Den Berg  A. Aziz  M. Machrus 《国际虫害防治杂志》2013,59(3):219-224

The incidence levels of moths and larvae of Etiella zinckenella were studied in the reproductive stage of soybean at eight farmers' field sites. A positive relationship was found between moths, caught by sweeping during flowering and pod-formation, and seed damage. Hence, rough predictions of damage can be made based on moth catches. Damage incidence was recorded in unsprayed plots and in plots sprayed with deltamethrin during flowering and pod-formation. Spraying did not affect the densities of moths and larvae or damage to pods and seeds. Larvae of H. armigera, Spodoptera litura and Plusiinae were not affected by spraying, but the pod-sucking bug Riptorus linearis, and two groups of predators, spiders and coccinellids, were reduced.  相似文献   

Role of product characteristics for the adoption of fruit and fruit product innovations     

M. Kraszewska  J. Zając  I. A. Van Der Lans  A. Jasiulewicz  I. Van Den Berg  A. Bolek 《The Journal of Horticultural Science and Biotechnology》2013,88(6):28-33

Summary

The aim of this study was the identification of those product characteristics that are important for the adoption of fruit and fruit product innovations by consumers. Sixteen focus group discussions were held in four European countries (Greece, The Netherlands, Poland, and Spain). Different aspects of six innovative fruit products were discussed, revealing those characteristics that were important for the adoption of each of them. It was observed that the participants did not perceive fruit innovations as a homogenous group, but assigned them to different groups, which led to a number of categories of fruit innovation. Three categories concerned the level of preparation of fruit. These were fresh, prepared, and processed fruit product innovations. Another two categories, radical and evolutionary innovations, related to the level of novelty of the fruit innovation. Characteristics important for the adoption of each of these categories are given. The results will be used for further, more quantitative, research.  相似文献   

Scavenging and active predation in generalist predators: A mesocosm study employing DNA-based gut content analysis     

K. von Berg  M. Traugott  S. Scheu 《Pedobiologia》2012,55(1):1-5

Scavenging presumably is common among invertebrate generalist predators, however, only few studies have specifically dealt with the consumption of dead prey. Here consumption of dead and living prey within a guild of generalist predators was investigated using mesocosm experiments and DNA-based gut content analysis. A community of predators including carabids, staphylinids and spiders was released into 0.2 m² mesocosms, planted with wheat and infested with grain aphids Sitobion avenae. At predator release, freshly killed bird cherry-oat aphids, Rhopalosiphum padi, were provided as carrion prey at the soil surface. Two days after predator release, predators were collected and their gut content screened for DNA of both aphid species using multiplex PCR. Comparing detection frequencies of DNA from living and dead prey, we found that all predators frequently consumed dead aphids, except for the lycosid spider Trochosa ruricola which exclusively fed on S. avenae. In contrast, in the tetragnathid spider Pachygnatha degeeri, supposed to feed mainly on living prey, detection rates of R. padi DNA were high. Our findings support previous assumptions that many generalist predators are facultative scavengers. This needs to be considered for the interpretation of field-derived data using approaches of gut content analyses as well as when assessing predators’ pest control potential.  相似文献   

Stenotrophomonas rhizophila DSM14405T promotes plant growth probably by altering fungal communities in the rhizosphere     

Christoph Stephan Schmidt  Mohamadali Alavi  Massimiliano Cardinale  Henry Müller  Gabriele Berg 《Biology and Fertility of Soils》2012,48(8):947-960

Stenotrophomonas rhizophila DSM14405^T is of high biotechnological interest as plant growth stimulator, especially for salinated conditions. The objective of this study was to determine the effect of plant species (cotton, tomato, and sweet pepper) on colonisation and plant growth promotion of this beneficial bacterium in gnotobiotic systems and in non-sterile soil. All plant structures (leaves, stems, and roots) were densely colonised by DSM14405^T reaching up to 10⁹ cells g^?1 fresh weight; under gnotobiotic conditions the abundances were 4–5 orders of magnitude higher than in non-sterile soil. Under non-sterile conditions and ambient humidity, tomato shoots were more densely colonised than shoots of sweet pepper and cotton. S. rhizophila DSM14405^T was shown to grow endophytically and colonise the vicinity of root hairs of tomato. Plant growth promotion was particularly apparent in tomato. In general, the impact of plant species on colonisation and plant growth promotion was more pronounced in soil than under gnotobiotic conditions and likely due to the control of diseases and deleterious microorganisms. S. rhizophila DSM14405^T was shown to control diseases in sweet pepper and in cotton. Molecular profiling via single strand conformation polymorphism of internal transcribed spacers and 16S rRNA genes (PCR-single strand conformational polymorphism (SSCP)) revealed that S. rhizophila DSM14405^T strongly affected fungal, but not bacterial communities in the rhizosphere of tomato and sweet pepper. Major SSCP bands related to uncultured fungi and Candida subhashii, disappeared in tomato rhizosphere after Stenotrophomonas treatment. This suggests an indirect, species-specific plant growth promotion effect of S. rhizophila via the elimination of deleterious rhizosphere organisms.  相似文献   

An assessment of the effectiveness of a large,national-scale invasive alien plant control strategy in South Africa     

Brian W. van Wilgen  Greg G. Forsyth  David C. Le Maitre  Andrew Wannenburgh  Johann D.F. Kotzé  Elna van den Berg  Lesley Henderson 《Biological conservation》2012,148(1):28-38

This paper presents an assessment of a large, national-scale alien plant control program that has operated in South Africa for 15 years. We reviewed data from three national-level estimates of the extent of invasion, records of the costs and spatial extent of invasive species control operations, assessments of the effectiveness of biological control, and smaller-scale studies. The 19 most important invasive taxa, mainly trees, in terrestrial biomes were identified. The effectiveness of control efforts on the extent of invasion of these taxa was assessed. Control costs over 15 years amounted to 3.2 billion rands (US$457 million), more than half of which was spent on 10 taxa, the most prominent being in the genera Acacia, Prosopis, Pinus and Eucalyptus. Despite substantial spending, control operations were in many cases applied to a relatively small portion of the estimated invaded area, and invasions appear to have increased, and remain a serious threat, in many biomes. Our findings suggest that South Africa’s national-scale strategy to clear invasive alien plants should be substantially modified if impacts are to be effectively mitigated. Rather than attempting to control all species, and to operate in all areas, a more focused approach is called for. This would include prioritising both the species and the areas, and setting goals and monitoring the degree to which they are achieved, within a framework of adaptive management. A greater portion of funding should also be directed towards biological control, where successes have been most notable.  相似文献   

Guidelines for the new nordic diet     

Mithril C  Dragsted LO  Meyer C  Blauert E  Holt MK  Astrup A 《Public health nutrition》2012,15(10):1941-1947

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Iodine-induced goitre and high prevalence of anaemia among Saharawi refugee women     

Henjum S  Barikmo I  Strand TA  Oshaug A  Torheim LE 《Public health nutrition》2012,15(8):1512-1518

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Udder health and female fertility traits are favourably correlated and support each other in multi-trait evaluations     

Buch LH  Sørensen MK  Lassen J  Berg P  Jakobsen JH  Johansson K  Sørensen AC 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2011,128(3):174-182

Genetic parameters were estimated for protein yield (PY), clinical mastitis (CM), somatic cell score, number of inseminations (NI) and days from calving to first insemination (CFI) in first‐parity Swedish Red cows by series of tri‐variate linear animal models. The heritability of PY was moderate (0.34 ± 0.004), and the heritabilities of the functional traits were all low (0.014 ± 0.001–0.14 ± 0.004). The genetic correlation between CM and CFI (0.38 ± 0.05) was stronger than the correlation between CM and NI (0.05 ± 0.06), perhaps because CM and CFI usually are observed in early lactation when the cow is likely to be in negative energy balance, whereas NI generally is recorded when the cow is not in negative energy balance any more. The genetic correlation between NI and CFI was very close to zero (?0.002 ± 0.05), indicating that these two fertility traits have different genetic backgrounds. All genetic correlations between PY and the functional traits were moderate and unfavourable, ranging from 0.22 ± 0.02 to 0.47 ± 0.03. In addition, the effect of including genetic and phenotypic correlations between the trait groups milk production, udder health and female fertility on the accuracy of the selection index was quantified for a heifer, a cow and a proven bull. The difference between the accuracy obtained by multi‐trait and single‐trait evaluations was largest for the cow (0.012) and small for the heifer and the bull (0.006 and 0.004) because the phenotype of the cow for one trait could assist in predicting the Mendelian sampling term for a correlated trait.  相似文献   

Nuclear magnetic resonance spectroscopy and chemometrics to identify pine nuts that cause taste disturbance     

Kobler H  Monakhova YB  Kuballa T  Tschiersch C  Vancutsem J  Thielert G  Mohring A  Lachenmeier DW 《Journal of agricultural and food chemistry》2011,59(13):6877-6881

Nontargeted 400 MHz (13)C and (1)H nuclear magnetic resonance (NMR) spectroscopy was used in the context of food surveillance to reveal Pinus species whose nuts cause taste disturbance following their consumption, the so-called pine nut syndrome (PNS). Using principal component analysis, three groups of pine nuts were distinguished. PNS-causing products were found in only one of the groups, which however also included some normal products. Sensory analysis was still required to confirm PNS, but NMR allowed the sorting of 53% of 57 samples, which belong to the two groups not containing PNS species. Furthermore, soft independent modeling of class analogy was able to classify the samples between the three groups. NMR spectroscopy was judged as suitable for the screening of pine nuts for PNS. This process may be advantageous as a means of importation control that will allow the identification of samples suitable for direct clearance and those that require further sensory analysis.  相似文献