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Pest Control (pest + control)
Selected AbstractsPesticide use in ornamental production: what are the benefits?PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 4 2009James A Bethke Abstract Pest control in ornamental production is challenging owing to the diversity of crops grown, the desired aesthetic perfection, the potential economic loss due to failure and the multitude of arthropod pests encountered. Agricultural crops of less value per acre, such as row crops, can tolerate a certain level of damage from arthropod pests without compromising yields. Damage thresholds for ornamentals, however, are essentially zero. Pesticides are a viable method of protection for such a crop in lieu of alternatives. Therefore, the purpose of this paper is to emphasize the importance of pesticides to the ornamental industry. Pesticides provide many benefits to ornamental producers, including: (1) consistent availability; (2) rapid kill; (3) reliable and consistent control; (4) increased crop production and quality; (5) they may be used to prevent movement of invasive pests; (6) they are less expensive (in general) than alternatives; (7) they may reduce plant pathogenic transmission; (8) they may be used in conjunction with natural enemies. Pesticide use will continue to be a significant strategy for dealing with arthropod pests so that ornamental producers can stay competitive in both national and international markets. Copyright © 2009 Society of Chemical Industry [source] Functional benefits of predator species diversity depend on prey identityECOLOGICAL ENTOMOLOGY, Issue 5 2005A. Wilby Abstract., 1.,Determining the functional significance of species diversity in natural enemy assemblages is a key step towards prediction of the likely impact of biodiversity loss on natural pest control processes. While the biological control literature contains examples in which increased natural enemy diversity hinders pest control, other studies have highlighted mechanisms where pest suppression is promoted by increased enemy diversity. 2.,This study aimed to test whether increased predator species diversity results in higher rates of predation on two key, but contrasting, insect pest species commonly found in the rice ecosystems of south-east Asia. 3.,Glasshouse experiments were undertaken in which four life stages of a planthopper (Nilaparvata lugens) and a moth (Marasmia patnalis) were caged with single or three-species combinations of generalist predators. 4.,Generally, predation rates of the three-species assemblages exceeded expectation when attacking M. patnalis, but not when attacking N. lugens. In addition, a positive effect of increased predator species richness on overall predation rate was found with M. patnalis but not with N. lugens. 5.,The results are consistent with theoretical predictions that morphological and behavioural differentiation among prey life stages promotes functional complementarity among predator species. This indicates that emergent species diversity effects in natural enemy assemblages are context dependent; they depend not only on the characteristics of the predators species, but on the identity of the species on which they prey. [source] Effects of agricultural diversification on the abundance, distribution, and pest control potential of spiders: a reviewENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2000Keith Sunderland Abstract A review of the literature showed that spider abundance was increased by diversification in 63% of studies. A comparison of diversification modes showed that spider abundance in the crop was increased in 33% of studies by ,aggregated diversification' (e.g. intercropping and non-crop strips) and in 80% of studies by ,interspersed diversification' (e.g., undersowing, partial weediness, mulching and reduced tillage). It is suggested that spiders tend to remain in diversified patches and that extending the diversification throughout the whole crop (as in interspersed diversification) offers the best prospects for improving pest control. There is little evidence that spiders walk in significant numbers into fields from uncultivated field edges, but diversification at the landscape level serves to foster large multi-species regional populations of spiders which are valuable as a source of aerial immigrants into newly planted crops. There are very few manipulative field studies where the impact of spiders on pests has been measured in diversified crops compared with undiversified controls. It is encouraging, however, that in those few studies an increased spider density resulted in improved pest control. Future work needs are identified. [source] Depensation: evidence, models and implicationsFISH AND FISHERIES, Issue 1 2001Liermann We review the evidence supporting depensation, describe models of two depensatory mechanisms and how they can be included in population dynamics models and discuss the implications of depensation. The evidence for depensation can be grouped into four mechanisms: reduced probability of fertilisation, impaired group dynamics, conditioning of the environment and predator saturation. Examples of these mechanisms come from a broad range of species including fishes, arthropods, birds, mammals and plants. Despite the large number of studies supporting depensatory mechanisms, there is very little evidence of depensation that is strong enough to be important in a population's dynamics. However, because factors such as demographic and environmental variability make depensatory population dynamics difficult to detect, this lack of evidence should not be interpreted as evidence that depensatory dynamics are rare and unimportant. The majority of depensatory models are based on reduced probability of fertilisation and predator saturation. We review the models of these mechanisms and different ways they can be incorporated in population dynamics models. Finally, we discuss how depensation may affect optimal harvesting, pest control and population viability analysis. [source] Beneficial links for the control of aphids: the effects of compost applications on predators and preyJOURNAL OF APPLIED ECOLOGY, Issue 4 2008James R. Bell Summary 1Polyphagous predators, such as spiders and beetles, perform a fundamental ecosystem service as regulators of agricultural pests, particularly aphids. They are most effective when they colonize the crop before the pest has reached its exponential growth phase. However, this is also when predators find themselves in a state of near-starvation. 2Predator numbers can be enhanced by applications of different types of organic matter, but the mechanism is not clearly understood. One hypothesis is that compost applied to the field may introduce a new detrital food chain to maintain predators until the pest arrives, but this may also be detrimental to effective pest control, fostering a surplus of alternative prey and causing a switch away from the pest. To elucidate these possible outcomes, we report on the use of within-field compost applications on aphids and their predators, presenting 4 years of field-scale manipulations. 3We found both direct and indirect links between compost, aphids and predators. In years when compost-treated plots had significantly higher numbers of predators, aphids were in significantly lower numbers than in plots without compost. Conversely, when there was a lack of response by predators, aphid numbers showed similar trends in all treatments. 4In all years, alternative prey responded strongly to compost application and did not fluctuate at the level shown by predators, suggesting that these two prey groups were decoupled. Instead, the predicted positive feedback of compost on predators numbers was either weak or absent. 5Synthesis and applications. The effect of compost on aphids clearly requires further practical refinement if it is to provide constant pest suppression, making it difficult to provide specific management recommendations at this stage. In the short term, compost application may not always confer immediate benefits in terms of pest control alone but this must be set against other better known benefits (moisture retention, nutrients). In the long term, experiments measuring the full trophic pathway are needed to unravel the effects of organic matter type, application time and the siting of compost relative to the crop in order to optimise pest suppression potential. [source] Teretrius nigrescens against larger grain borer Prostephanus truncatus in African maize stores: biological control at work?JOURNAL OF APPLIED ECOLOGY, Issue 2 2003Niels Holst Summary 1Following the accidental introduction of the bostrichid beetle Prostephanus truncatus into East and West Africa around 1980, a classical biological control campaign was launched in 1991; the histerid beetle Teretrius nigrescens was released as a biocontrol agent to prevent the destructive outbreak of the pest in small-farm maize stores. However, while the campaign has been ongoing, so has discussion in the scientific community about the merits of this campaign and its chances of success. 2From published and unpublished data from experimental maize stores in Benin, West Africa, we derived statistical models describing the in-store insect population dynamics, and were thus able to point out significant biological interactions and to explain the observed lack of biological control. 3We found that (i) T. nigrescens reduced significantly the population growth rate of both P. truncatus and the non-target pest, the weevil Sitophilus zeamais; (ii) T. nigrescens displayed a positive numerical response to both prey species, P. truncatus and S. zeamais; (iii) asymmetric competition existed between the two prey species, S. zeamais was negatively affected by P. truncatus but not vice versa; (iv) T. nigrescens and S. zeamais displayed negative intraspecific density-dependence whereas P. truncatus was resource-limited. 4We conclude that classical biological control with T. nigrescens is not likely to become successful, mainly due to the predator's intraspecific density-dependence and its low population growth rate compared with its prey. We recommend that further research on P. truncatus integrated pest management takes into account the farmer as an active agent managing the store. 5Synthesis and applications. When biocontrol does not result in satisfactory pest control, as in the case of P. truncatus, farmers should learn how to scout for the pest and take action when a need is detected. In areas where the pest is usually only a minor problem, the agricultural extension service should consider setting up a simple early warning system for their region. When attempts at classical biological control remain unsuccessful, as in the case of P. truncatus now for 10 years, policy-makers should prioritize training of extension service and farmers in integrated pest management techniques (e.g. need-based use of insecticides) as a necessary supplement to biocontrol. [source] The ecological challenge of immunocontraception: editor's introductionJOURNAL OF APPLIED ECOLOGY, Issue 6 2000N.D. Barlow Summary 1. ,The problems of vertebrate pests are greater now than ever before, with vertebrate control constrained by problems of humaneness, scale and environmental impact. However, immunocontraception involves a conceptually ideal solution. Although not intrinsically novel, its delivery in baits or by a self-spreading vector and its effectiveness in pest control, are now the focus of growing international interest. 2. ,Major ecological questions correspond to the two forms of delivery: baits and vectors. First, given an effective immunocontraceptive, inserted into a bait and eaten by a pest, would the resulting level of sterilization in the population effectively suppress densities? Secondly, given that the immunocontraceptive agent can be inserted into a microparasitic or macroparasitic infective vector, would the modified vector persist at sufficient prevalence in the host population, and hence suppress densities to the required extent? 3. ,The papers published in this Special Profile focus on behaviour following sterilization or they model the likely impact of viral-vectored immunocontraception. They highlight advantages and disadvantages of immunocontraception and some general, novel and specific issues. These include the possibility of behaviourally mediated population responses to fertility control; the possible advantages of a mixed baiting and vector strategy; the competitiveness of a modified vector; the appropriateness of immunocontraception for controlling invasive vertebrates on islands; and the need for a ,pay-off' methodology for assessing genetic modifications against alternatives. 4. ,The findings offer significant benefits for management and policy: they will inform decisions on whether to pursue immunocontraception as a control option, and they provide evidence about efficacy and risk in applications to release genetically modified vectors. 5. ,Although many of the problems in developing immunocontraception technology are biotechnological, questions about the effectiveness of immunocontraceptive pest control are ultimately in the domain of ecologists. [source] Pests, pesticide use and alternative options in European maize production: current status and future prospectsJOURNAL OF APPLIED ENTOMOLOGY, Issue 5 2010M. Meissle Abstract Political efforts are made in the European Union (EU) to reduce pesticide use and to increase the implementation of integrated pest management (IPM). Within the EU project ENDURE, research priorities on pesticide reduction are defined. Using maize, one of the most important crops in Europe, as a case study, we identified the most serious weeds, arthropod pests, and fungal diseases as well as classes and amounts of pesticides applied. Data for 11 European maize growing regions were collected from databases, publications and expert estimates. Silage maize dominates in northern Europe and grain production in central and southern Europe. Crop rotations range from continuous growing of maize over several years to well-planned rotation systems. Weeds, arthropod pests and fungal diseases cause economic losses in most regions, even though differences exist between northern countries and central and southern Europe. Several weed and arthropod species cause increasing problems, illustrating that the goal of reducing chemical pesticide applications is challenging. Pesticides could potentially be reduced by the choice of varieties including genetically modified hybrids, cultural control including crop rotation, biological control, optimized application techniques for chemicals, and the development of more specific treatments. However, restrictions in the availability of alternative pest control measures, farm organization, and the training and knowledge of farmers need to be overcome before the adoption of environmentally friendly pest control strategies can reduce chemical pesticides in an economically competitive way. The complex of several problems that need to be tackled simultaneously and the link between different control measures demonstrates the need for IPM approaches, where pest control is seen in the context of the cropping system and on a regional scale. Multicriteria assessments and decision support systems combined with pest monitoring programs may help to develop region-specific and sustainable strategies that are harmonized within a EU framework. [source] Evidences of non-additive effects of multiple parasitoids on Diatraea saccharalis Fabr. (Lep., Crambidae) populations in sugarcane fields in BrazilJOURNAL OF APPLIED ENTOMOLOGY, Issue 2 2004M. N. Rossi Abstract: Biological control is a relatively benign method of pest control. However, considerable debate exists over whether multiple natural enemies often interact to produce additive or non-additive effects on their prey or host populations. Based on the large data set stored in the São João and Barra sugarcane mills (state of São Paulo, Brazil) regarding the programme of biological control of Diatraea saccharalis using the parasitoids Cotesia flavipes and tachinid flies, in the present study the author investigated whether the parasitoids released into sugarcane fields interfered significantly with the rate of parasitized D. saccharalis hosts. The author also observed whether there was an additive effect of releasing C. flavipes and tachinids on the rate of parasitized hosts, and looked for evidence of possible negative effects of the use of multiple parasitoid species in this biological control programme. Results showed that C. flavipes and the tachinids were concomitantly released in the Barra Mill, but not in the São Jão Mill. Furthermore, in the Barra Mill there was evidence that the parasitoids interacted because the percentage of parasitism did not increase after the release of either C. flavipes or tachinids. In the São João Mill, when both parasitoid species were released out of synchrony, both the percentage of parasitism by C. flavipes as well as that of the tachinids increased. When large numbers of tachinids were released in the Barra Mill, they caused a significant lower percentage of parasitism imposed by C. flavipes. The implications of the results as evidence of non-additive effects of C. flavipes plus tachinids on D. saccharalis populations are discussed. [source] A review of changes in the fish assemblages of Levantine inland and marine ecosystems following the introduction of non-native fishesJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2005M. Goren Summary The arrival of non-native fishes in the Levant Basin began in the late 19th century. Whereas the presence of most of the 40 non-native freshwater fishes stem from intentional introductions, either for aquaculture or pest control, the 62 species of non-native marine fishes arrived by natural dispersal via the Suez Canal. Of the non-native freshwater species, five have established successful breeding populations (mosquitofish Gambusia affinis, common carp Cyprinus carpio, crucian carp Carassius carassius, swordtail Xiphophorus hellerii and rainbow trout Oncorhynchus mykiss), and seven are regularly stocked in natural habitats (thinlip mullet Liza ramada, flathead mullet Mugil cephalus, European eel Anguilla anguilla, grass carp Ctenopharyngodon idella, Asian silver carp Hypophthalmichthys molitrix, bighead carp Aristichthys nobilis, black carp Mylopharyngodon piceus). Some non-native species appear to have out-competed native species. Gambusia affinis may have caused the extirpation of two native cyprinid fishes from the Qishon River basin (Levant silver carp Hemigrammocapoeta nana and common garra Garra rufa) and the southern Dead Sea (endemic Sodom's garra G. ghoerensis). The opening of the Suez Canal in 1869 allowed entry into the eastern Mediterranean of Indo-Pacific and Erythrean biota, with the latter now dominating the community structure (50,90% of fish biomass) and function (altered native food web) of the Levantine littoral and infra-littoral zones. The process has accelerated in recent years concurrent with a warming trend of the seawater. Record numbers of newly discovered non-native species is leading to the creation of a human-assisted Erythrean biotic province in the eastern Mediterranean. [source] Wolbachia -induced unidirectional cytoplasmic incompatibility and the stability of infection polymorphism in parapatric host populationsJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 2 2007M. FLOR Abstract Wolbachia are intracellular, maternally inherited bacteria that are widespread among arthropods and commonly induce a reproductive incompatibility between infected male and uninfected female hosts known as unidirectional cytoplasmic incompatibility (CI). If infected and uninfected populations occur parapatrically, CI acts as a post-zygotic isolation barrier. We investigate the stability of such infection polymorphisms in a mathematical model with two populations linked by migration. We determine critical migration rates below which infected and uninfected populations can coexist. Analytical solutions of the critical migration rate are presented for mainland-island models. These serve as lower estimations for a more general model with two-way migration. The critical migration rate is positive if either Wolbachia causes a fecundity reduction in infected female hosts or its transmission is incomplete, and is highest for intermediate levels of CI. We discuss our results with respect to local adaptations of the Wolbachia host, speciation, and pest control. [source] Influence of within-field position and adjoining habitat on carabid beetle assemblages in winter wheatAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2010M. Anjum-Zubair 1The influence of within-field position and adjoining habitat on carabid beetles was studied in 20 winter wheat fields in ten different Swiss agricultural landscapes. In each landscape, two winter wheat fields (one with adjoining sown wildflower area and one with adjoining grassy margin) were investigated. 2Carabid beetles were caught in pitfall traps 3 and 30 m from the edge in each of the 20 wheat fields. Significantly more individuals were found in the centres (30-m position) than at the edges (3-m position). Conversely, species richness was significantly higher at the field edges than in the centres. 3Of the ten most abundant species, Poecilus cupreus, Agonum muelleri and Pterostichus melanarius were significantly more abundant in the field centres than at the edges. Harpalus rufipes was significantly more abundant in the fields adjoining sown wildflower areas than in the fields adjoining grassy margins. 4In conclusion, the response of carabid beetles to within-field position and adjoining habitats was species specific. This needs to be taken into account in habitat management for biodiversity conservation and pest control. [source] Fertilizer affects the behaviour and performance of Plutella xylostella on brassicasAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2009Joanna T. Staley Abstract 1,Foliar nitrogen concentration, which can be manipulated in crop plants by fertilizer supply, has long been recognized as a major factor in phytophagous insect abundance and performance. More recently, the type of fertilizer supplied has been shown to influence the abundance of some herbivore species. The diamondback moth Plutella xylostella is a global pest of Brassica crops. Although it has been the subject of numerous studies on host-plant resistance and pest control, few studies have addressed the effect of abiotic factors, such as nutrient supply, on its performance and behaviour. 2,We assessed oviposition preference, larval feeding preference and larval performance of P. xylostella on two cultivars of Brassica oleracea. Plants were grown using two fertilizer types, John Innes fertilizer and an organic animal manure, at high and low concentrations. 3,Plutella xylostella laid more eggs on cultivar Derby Day than Drago. Derby Day was also the cultivar on which larval performance was maximized. However, differences in larval performance between cultivars were only found when plants were grown in compost with John Innes fertilizer, and not when fertilized with animal manure. 4,Foliar nitrogen concentration was greater in plants grown in high fertilizer treatments but did not differ between cultivars. The concentrations of three glucosinolate compounds (glucoiberin, sinigrin and glucobrassicin) were greater in the high fertilizer treatments. Glucosinolate concentrations were higher in the Drago than the Derby Day cultivar. 5,These results are discussed in relation to the preference-performance hypothesis, and the assessment of plant resistance differences between cultivars using different types of fertilizer. [source] Effects of ground cover (straw and compost) on the abundance of natural enemies and soil macro invertebrates in vineyardsAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2007Linda J. Thomson Abstract 1,Herbicides are commonly applied under grapevines in Australia to remove weeds and thereby to avoid water loss through transpiration. 2,Interest in sustainability promotes a reduction in chemical inputs, including herbicides, leading to trials with surface mulches to suppress weeds. 3,Surface mulches may also influence the abundance of a range of invertebrates. Potentially, an increase in natural enemies will contribute to pest control and encourage a reduction in pesticide application. 4,We used three trapping methods and direct soil sampling to assess invertebrates at ground level, in the canopy and in the soil to determine the influence of mulch on natural enemies, potential pests and soil macroinvertebrates, including earthworms. 5,Collections sorted to family demonstrated that the addition of straw or compost mulches increased natural enemies collected with pitfall traps and soil organisms. However, there was no clear indication of the overall superiority of either mulch. 6,Abundance of ground beetles, parasitoid Hymenoptera and spiders collected with pitfall traps were increased by the addition of mulches. In the canopy, predatory and parasitic Diptera and predatory Hemiptera increased after mulching. 7,Earthworms collected by hand sorting soil increased with straw mulching. 8,No influence on pests was detected. Although Lepidoptera and Sigmurethra, collected in pitfall traps, increased with straw mulching, neither included pest species. 9,The results are discussed with reference to the potential economic impact of mulches. [source] Are the ecological concepts of assembly and function of biodiversity useful frameworks for understanding natural pest control?AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2002Andrew Wilby First page of article [source] Effects of reduced-rate methyl bromide applications under conventional and virtually impermeable plastic film in perennial crop field nurseriesPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 8 2010Bradley D Hanson Abstract BACKGROUND: Producers of perennial crop nursery stock in California use preplant soil fumigation to meet state phytosanitary requirements. Although methyl bromide (MB) has been phased out in many agricultural industries, it is still the preferred treatment in the perennial nursery industry and is used under Critical Use Exemptions and Quarantine/Preshipment provisions of the Montreal Protocol. The present research was conducted to evaluate reduced-rate MB applications sealed with conventional and low-permeability plastic films compared with the primary alternative material. RESULTS: Reduced rates (100,260 kg ha,1) of MB applied in combination with chloropicrin (Pic) and sealed with a low-permeability plastic film provided weed and nematode control similar to the industry standard rate of 392 kg ha,1 MB:Pic (98:2) sealed with high-density polyethylene (HDPE) film. However, the primary alternative chemical, 1,3-dichloropropene (1,3-D), tended to provide slightly lower pest control even on sites with relatively low plant parasitic nematode, soil-borne pathogen and weed pest pressure. CONCLUSION: If California regulations change to allow the use of low-permeability films in broadcast fumigant applications, the results of this research suggest that reduced rates of MB in perennial crop nurseries could serve as a bridge strategy until more technically, economically and environmentally acceptable alternatives are developed. Published 2010 by John Wiley & Sons, Ltd. [source] What can pest management learn from laboratory animal ethics?PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 3 2010James Yeates Abstract There remains a lack of a clear overarching policy framework for decision-making in pest control programmes. In comparison, ethical principles have been extensively developed for scientific procedures, such as those underlying the UK's Animals (Scientific Procedures) Act 1986. This paper assesses the extent to which the principles and methodology underlying the act and secondary guidance could be used to provide principles of rodent management. Useful principles include that any programme has a legitimate purpose; that methods are used only if the harms are outweighed by the benefits; that harms are minimised by refinement, replacement and reduction and that there is personal responsibility. The usefulness and implications for pest control of each principle and the overall approach are discussed. Copyright © 2009 Society of Chemical Industry [source] The promise of insect genomicsPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 5 2007Cornelis JP Grimmelikhuijzen Insects are the largest animal group in the world and are ecologically and economically extremely important. This importance of insects is reflected by the existence of currently 24 insect genome projects. Our perspective discusses the state-of-the-art of these genome projects and the impacts that they have on basic insect science and pest control. Copyright © 2007 Society of Chemical Industry [source] Rodenticide grain bait ingredient acceptance by Norway rats (Rattus norvegicus), California ground squirrels (Spermophilus beecheyi) and pocket gophers (Thomomys bottae)PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 7 2006Terrell P Salmon Abstract Vertebrate pest control in California is often accomplished through the use of rodenticide grain baits. These grain baits are composed of steam-rolled oats (SRO), a toxicant, an indicator dye and an oil combination. A series of tests were performed to determine the effects of various dye and oil formulations on acceptance of grain bait by Norway rats [Rattus norvegicus (Berk)], California ground squirrels [Spermophilus beecheyi (Richardson)] and pocket gophers (Thomomys bottae Eyd & Gerv). Seven different dyes, four oil formulations and clean (untreated) oats were tested for acceptance. The addition of the selected oils and dyes to grain resulted in no significant differences in consumption. This indicates that there is a wide variety of dyes that could be used in the formulation of rodenticides. These alternatives could aid in proper pesticide use, the deterrence of bait consumption by birds and possibly in ingredient adhesion to the finished bait. Copyright © 2006 Society of Chemical Industry [source] Insect peptide hormones: a selective review of their physiology and potential application for pest controlPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 10 2003Gerd Gäde Abstract Our knowledge on primary structure, synthesis, release, receptor binding, structure,activity relationships, mode of action and degradation of, mainly, neuropeptides from insects has increased dramatically during the last 10 years or so. Here, five case studies are presented, which deal selectively with effects on: reproduction (trypsin modulating oostatic factor in mosquito); energy metabolism, locomotion and the immune system (adipokinetic hormones); water and ion balance, and feeding behaviour (diuretic hormones, kinins, sulfakinins); sex attraction (pheromone biosynthesis activating neuropeptide); and growth and development, and muscle activity (allatostatins). The literature is reviewed in the context of how the knowledge on neuropeptides has been and can be used for the design of novel, safe and selective compounds to control pest insects in the foreseeable future. Copyright © 2003 Society of Chemical Industry [source] Effects of Xenobiotic Compounds on Cell Activities in Euplotes crassusTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2005FRANCESCA TRIELLI It is now widely accepted that Protists are relevant bioassays to be exploited for the study of environmental modifications due to the presence of xenobiotic compounds. In this work, we evaluated the possibility of utilizing Euplotes crassus, an interstitial marine ciliate, for the pre-chemical screening of environmental sites, such as estuarine and coastal sediments. With this aim, we tested the sensitivity of E. crassus to exposure to three classes of pollutants: an organophosphate neurotoxic drug, basudin, largely used for pest control in agricultural sites, a toxic heavy metal, mercury (HgCl2), and an aromatic polycyclic hydrocarbon, benzopyrene (BP). We found a dose-dependent effect of these compounds on cell viability at concentrations ranging from 1/102 v/v to 1/107 v/v for basudin, from 5 ,M to 0.1 ,M for HgCl2, and from 50 ,M to 1 ,M for BP. In particular, 100% mortality was caused by a 1-h exposure to 1/105 v/v basudin, or 2 ,M HgCl2, or 25 ,M BP, and by a 24-h exposure to 1/106 v/v basudin, 0.5 ,M HgCl2, or 5 ,M BP. A significant decrease in the daily mean fission rate (P<0.001) was found after exposure to 1/107 v/v basudin, or 0.25 ,M HgCl2, or 1 ,M BP. Moreover, as it is well known that the inhibition of acetylcholinesterase (AChE) activity represents a specific biomarker for neurotoxic drugs, we first detected this enzyme activity in E. crassus, using cytochemical, spectrophotometric, and electrophoretic methods; then, AChE activity was characterized by its sensitivity to specific AChE inhibitors and to variations in pH and temperature. Like AChE present in higher organisms, the AChE activity detected in E. crassus was inhibited by exposure to basudin. Conversely, exposure to HgCl2, or PB did not inhibit AChE activity, but caused a significant reduction in lysosomal membrane stability. [source] Predicting the unexpected: using a qualitative model of a New Zealand dryland ecosystem to anticipate pest management outcomesAUSTRAL ECOLOGY, Issue 4 2009DAVID S. L. RAMSEY Abstract Pest management is expensive and there is often uncertainty about the benefits for the resources being protected. There can also be unintended consequences for other parts of the ecosystem, especially in complex food webs. In making decisions managers generally have to rely on qualitative information collected in a piecemeal fashion. A method to assist decision making is a qualitative modelling approach using fuzzy cognitive maps, a directed graphical model related to neural networks that can take account of interactions between pests and conservation assets in complex food webs. Using all available information on relationships between native and exotic resources and consumers, we generated hypotheses about potential consequences of single-species and multi-species pest control on the long-term equilibrium abundances of other biotic components of an ecosystem. We applied the model to a dryland ecosystem in New Zealand because we had good information on its trophic structure, but the information on the strength of species interactions was imprecise. Our model suggested that pest control is unlikely to significantly boost native invertebrates and lizards in this ecosystem, suggesting that other forms of management may be required for these groups. Most of the pest control regimes tested resulted in greater abundances of at least one other pest species, which could potentially lead to other management problems. Some of the predictions were unexpected, such as more birds resulting from possum and mouse control. We also modelled the effects of an increase in invasive rabbits, which led to unexpected declines of stoats, weasels, mice and possums. These unexpected outcomes resulted from complex indirect pathways in the food web. Fuzzy cognitive maps allow rapid construction of prototype models of complex food webs using a wide range of data and expert opinion. Their utility lies in providing direction for future monitoring efforts and generating hypotheses that can be tested with field experiments. [source] The impact of aphicide drenches on Micromus tasmaniae (Walker) (Neuroptera: Hemerobiidae) and the implications for pest control in lettuce cropsAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 3 2006Peter G Cole Abstract, The recent arrival of lettuce aphid (Nasonovia ribis-nigri (Mosley) ) in Australia has resulted in a pesticide-based protection program based upon seedling drenches of imidacloprid being promoted by many advisory agencies and accepted by growers as the only option available. This has caused concern about potential for incompatibility with existing integrated pest management programs for other pests in lettuce. Two neonicotinoid insecticides, imidacloprid (Confidor 200SC) and thiamethoxam (Actara), were applied to lettuce seedlings by drenching. A model aphid (Macrosiphum euphorbiae (Thomas) ), used because N. ribis-nigri was not present in mainland Australia at that time, was periodically released onto the seedlings over 10 weeks. The effects of imidacloprid and thiamethoxam on larvae of predatory brown lacewings (Micromus tasmaniae (Walker) ) which fed on the aphids were measured over 10 weeks by bioassay. Imidacloprid applied at a rate of 11 mL active ingredient (ai) per 1000 seedlings and thiamethoxam applied at 0.5 g ai per 1000 seedlings were highly toxic to M. tasmaniae that consumed aphids from the seedlings for up to 4 weeks after application. A 1/10 rate of imidacloprid (1.1 mL ai per 1000 seedlings) caused moderate toxicity for 3 weeks, and was then harmless to M. tasmaniae. Thiamethoxam and the high rate of imidacloprid caused almost complete mortality of aphids for about 6 weeks after application, and the low rate of imidacloprid displayed similarly high activity for about 3 weeks. [source] Bioengineering nitrogen acquisition in rice: can novel initiatives in rice genomics and physiology contribute to global food security?BIOESSAYS, Issue 6 2004Dev T. Britto Rice is the most important crop species on earth, providing staple food for 70% of the world's human population. Over the past four decades, successes in classical breeding, fertilization, pest control, irrigation and expansion of arable land have massively increased global rice production, enabling crop scientists and farmers to stave off anticipated famines. If current projections for human population growth are correct, however, present rice yields will be insufficient within a few years. Rice yields will have to increase by an estimated 60% in the next 30 years, or global food security will be in danger. The classical methods of previous green revolutions alone will probably not be able to meet this challenge, without being coupled to recombinant DNA technology. Here, we focus on the promise of these modern technologies in the area of nitrogen acquisition in rice, recognizing that nitrogen deficiency compromises the realization of rice yield potential in the field more than any other single factor. We summarize rice-specific advances in four key areas of research: (1) nitrogen fixation, (2) primary nitrogen acquisition, (3) manipulations of internal nitrogen metabolism, and (4) interactions between nitrogen and photosynthesis. We develop a model for future plant breeding possibilities, pointing out the importance of coming to terms with the complex interactions among the physiological components under manipulation, in the context of ensuring proper targeting of intellectual and financial resources in this crucial area of research. BioEssays 26:683,692, 2004. © 2004 Wiley Periodicals, Inc. [source] Structure Determination of an Organometallic 1-(Diazenylaryl)ethanol: A Novel Toxin Subclass from the Web of the Spider Nephila clavipesCHEMISTRY & BIODIVERSITY, Issue 6 2004Maurício, Ribeiro Marques A novel chemical subclass of toxin, [1-(3-diazenylphenyl)ethanol]iron, was identified among the compounds present in the web of the spider Nephila clavipes. This type of compound is not common among natural products, mainly in spider-venom toxins; it was shown to be a potent paralytic and/or lethal toxin applied by the spider over its web to ensure prey capture only by topical application. The structure was elucidated by means of ESI mass spectrometry, 1H-NMR spectroscopy, high-resolution (HR) mass spectrometry, and ICP spectrometry. The structure of [1-(3-diazenylphenyl)ethanol]iron and the study of its insecticidal action may be used as a starting point for the development of new drugs for pest control in agriculture. [source] | ||||||||||||||||