Population dynamics of Anarsia lineatella in relation to crop damage and the development of economic injury levels

Developing a relationship between pest abundance and damage to crops is essential for the calculation of economic injury levels (EILs) and to anticipate informed management decisions. Field studies were conducted for three successive years (2005, 2006 and 2007) in peach orchards of northern Greece to examine relationships between densities of Anarsia lineatella Zeller (Lepidoptera: Gelechiidae) populations and peach (Prunus persica) yields. According to a linear regression model, the increase in moth’s densities during the 1st flight resulted in a significant reduction in yield (y = 0.436x + 10.22, R² = 0.635, d.f. = 2,11, P < 0.05). Correlation of male moths captured during the 2nd flight and observed yield loss was significant (y = 0.5231x + 17.204, R² = 0.792, d.f. = 2,11, P < 0.05). Moreover, according to a linear model by counting the number of shoot strikes, during the first observation period, a forthcoming yield loss can be estimated (y = 27.389x?6.304, R² = 0.711, d.f. 2,11, F = 22.09, P < 0.05). A significant relationship was observed between the numbers of the 2nd generation larvae and yield loss (y = 163x, R² = 0.890). Regression coefficient of the above function represents yield loss per pest and was applied in the calculation of EIL’s and fixed Economic thresholds (ET’s). In addition, parameter of the price commodity was estimated for 2009 by applying stochastic autoregressive moving average model. By integrating above information, EIL and fixed ET estimated as 112 larvae and 84 larvae per sampling unit for a mean value (€4/0.1 ha) of cost management tactics and a 90% efficacy.     

Developing a risk indicator to comparatively assess environmental risks posed by microbial and conventional pest control agents

Selected biological control agents and conventional pesticides were used to critically review the applicability of a newly developed Risk Indicator (RI) system. Five basic components are proposed for the calculation of the overall environmental risk score: persistence of the active ingredient, dispersal potential, range of non-target organisms that are affected, and direct and indirect effects on the ecosystem. Several risk measurement systems were reviewed; risk categories in the proposed system were modified from a model developed for classical biocontrol agents. Additionally, one new category was included, to assess the risks to vertebrate non-target species. Besides a detailed discussion of the new RI model, the suitability of the model was demonstrated by calculating the risk scores for 17 selected products. It became obvious that the environmental risk score varied greatly within the assessed chemical products, and also within the group of biological products. The use pattern greatly influenced the estimated environmental risk posed by any given product. The overall environmental risk score varied between a very low risk score of 24 (Coniothyrium minitans, soil application) and a near maximum risk score of 4275 (high risk reference DDT, foliar spray). The proposed model can be used to communicate environmental risk and to design lower risk integrated pest management strategies. It is suggested that the proposed RI system may serve to define low risk and reduced risk pesticides. Yet, it remains debatable whether the RI will be useful in determining acceptability of data waivers for regulatory purposes.     

一种基于PCR技术鉴定单拷贝转基因烟草的方法

为了鉴定携带单拷贝外源基因的转基因烟草植株,以烟草核基因组上已知的单拷贝内源基因（RNR2）为内参,转基因烟草植株基因组DNA为模板,在同一PCR反应体系中扩增内源基因（RNR2）和外源目的基因（NPTⅡ）。反应产物在琼脂糖凝胶上电泳,获得了预期大小的两条特异性扩增条带。经ImageJ软件捕捉分析两条目的条带的灰度比,当T1代转基因烟草植株中外源基因与内源基因的扩增条带灰度比为1时,所检测植株即为单拷贝外源基因的转基因烟草植株。孟德尔经典遗传学方法证实了上述检测结果高度可信。     

Impact of citrus thrips chemical treatments on the predatory mite Euseius tularensis

Abstract:  The impacts of four pesticides used for control of citrus thrips, Scirtothrips citri (Moulton), were evaluated in both field and laboratory populations of a predaceous mite, Euseius tularensis Congdon. Abamectin and chlorfenapyr had the least impact of pesticides evaluated on a field population of E. tularensis and predaceous mite levels mirrored those observed in the untreated control but at a slightly depressed level. Spinosad reduced predaceous mites somewhat but they recovered to 50% of the level in the untreated control by the end of the trial. Mite populations were low throughout the trial in plots treated with cyfluthrin. As an overall summary statistic, cumulative predator mite-days ranged from 73.6% of the level observed in the untreated control with abamectin to 67.1% with chlorfenapyr, 36.8% with spinosad and 11.7% with cyfluthrin. Three additional field trials confirmed abamectin's minimal impact. In laboratory studies of adult female mite mortality on field-weathered, pesticide-treated leaves, cyfluthrin caused high mortality on day 1 after treatment and all mites that were not killed were driven off leaf discs until day 21. When mites were placed on leaf discs 1 day after treatment with abamectin, spinosad, or chlorfenapyr, 67.5% of the mites died on chlorfenapyr discs. By 7 days after treatment, no material but cyfluthrin showed a significant impact. Implications to citrus integrated pest management are discussed.     

Pollen limitation meets resource allocation: towards a comprehensive methodology

The standard method of measuring pollen limitation is to add pollen to a number of flowers, preferably to a whole plant, and to compare fruit and seed set with that of naturally pollinated flowers on other plants. In 25 yr of research, this method has yielded valuable data, but it is difficult to use in large plants. This has caused a bias in the available data towards smaller, herbaceous plants with relatively few flowers. I argue that, in order to widen our knowledge of how pollen limitation affects plants, we should go beyond whole-plant pollen addition and change our concept of how a flowering plant functions. The traditional method does not take into account the variation in and dynamics of resource allocation and pollen availability. The concept of integrated physiological units (IPUs) does, but, although it has been applied to pollination biology, it has not received the attention it deserves. I use this article to present its merits again, to propose a step-by-step methodology for studying pollen limitation, and to examine factors influencing possible plant strategies.     

Phenylalanine promotes interaction of transmembrane domains via GxxxG motifs

Interactions of transmembrane helices play a crucial role in the folding and oligomerisation of integral membrane proteins. In order to uncover novel sequence motifs mediating these interactions, we randomised one face of a transmembrane helix with a set of non-polar or moderately polar amino acids. Those sequences capable of self-interaction upon integration into bacterial inner membranes were selected by means of the ToxR/POSSYCCAT system. A comparison between low/medium-affinity and high-affinity sequences reveals that high-affinity sequences are strongly enriched in phenylalanine residues that are frequently observed at the − 3 position of GxxxG motifs, thus yielding FxxGxxxG motifs. Mutation of Phe or GxxxG in selected sequences significantly reduces self-interaction of the transmembrane domains without affecting their efficiency of membrane integration. Conversely, grafting FxxGxxxG onto unrelated transmembrane domains strongly enhances their interaction. Further, we find that FxxGxxxG is significantly over-represented in transmembrane domains of bitopic membrane proteins. The same motif contributes to self-interaction of the vesicular stomatitis virus G protein transmembrane domain. We conclude that Phe stabilises membrane-spanning GxxxG motifs. This is one example of how the role of certain side-chains in helix-helix interfaces is modulated by sequence context.     

Chimpanzee facial symmetry: a biometric measure of chimpanzee health

This paper reports a study of fitness indicator theory in chimpanzees. First, it establishes a theoretical perspective for the study of fitness indicator theory and the relationships among indicators of fitness in humans and other animals. Second, it describes a methodology for assessing facial fluctuating asymmetry (FA) in a sample (N = 21) of zoo chimpanzees (Pan troglodytes). Third, associations among chimpanzee facial FA and health are described. FA was positively associated with negative health symptoms, and negatively associated with general health. Results are discussed under the framework of good genes theory.     

An automated protein annotation filter for integrating web-based annotation tools

A wide range of web based prediction and annotation tools are frequently used for determining protein function from sequence. However, parallel processing of sequences for annotation through web tools is not possible due to several constraints in functional programming for multiple queries. Here, we propose the development of APAF as an automated protein annotation filter to overcome some of these difficulties through an integrated approach.     

Common and Uncommon Understory Species Differentially Respond to Restoration Treatments in Ponderosa Pine/Douglas-Fir Forests, Montana

Restoration treatments have been widely advocated to address declining conditions in Pinus ponderosa forests throughout the western United States. However, few studies have examined treatment effects on individual plant species or whether responses differ for common species and uncommon species (those with low abundance in the community)—information that may be critical in managing for long‐term biodiversity. We investigated understory species responses to restoration treatments in ponderosa pine/Douglas‐fir forests using a randomized block experimental design with three blocks and four treatments (control, burn‐only, thin‐only, and thin‐burn). Understory vegetation was sampled before treatment and for three consecutive years after treatment. We used richness and an index of uniqueness to compare responses of common and uncommon native understory species among treatments, and indicator species analysis to identify individual species that responded to each treatment. Treatments that included thinning had significantly more unique species assemblages than the control. The thin‐only treatment increased common native species richness, whereas all active treatments significantly increased uncommon native species richness over the control, especially the thin‐burn. Generally, life‐forms did not explain the responses of individual species, though in the final sampling year several graminoids were exclusively indicative of treatments that included thinning. Very few species had reduced abundance in the thinning and burning treatments by the final sample year, whereas many uncommon and short‐lived species benefited from active treatments, especially the combined thin‐burn treatment. Active restoration treatments in these forests may foster plant diversity by minimally impacting common species while significantly benefiting disturbance‐dependent native species.