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Flower Thrips (flower + thrips)
Kinds of Flower Thrips Selected AbstractsDensity, dispersal, and feeding impact of western flower thrips (Thysanoptera: Thripidae) on flowering chrysanthemum at different spatial scalesECOLOGICAL ENTOMOLOGY, Issue 1 2005Marc Rhainds Abstract., 1. This study evaluated the effect of dispersal on the density and feeding impact of a phytophagous insect in relation to the spatial distribution of its host plants. 2. The interaction between density, dispersal, and feeding impact of western flower thrips on flowering chrysanthemum was quantified at three spatial scales, with infested and uninfested plants either isolated in 0.25 m2 individual cages, or enclosed together in 2.25 m2 communal cages or 75 m2 greenhouses. 3. In individual cages, the rate of dispersal from chrysanthemum plants to blue sticky traps increased with the density of thrips for females but not males. Uninfested plants consistently had fewer thrips when they were individually caged rather than enclosed with plants infested with adults, indicating that dispersal mediates inter-plant distribution of thrips. 4. The feeding impact of thrips on inflorescences was evaluated using the absorbance of ethanol extracts at wavelengths characteristic of yellow carotenoid pigments associated with chrysanthemum inflorescences (415, 445, and 472 nm). Increasing absorbance of extracts with increasing density of thrips per inflorescence suggests that feeding by thrips results in ruptured cells leaching carotenoid pigments. 5. In communal cages, the distribution of thrips was uniform for infested and uninfested plants, whereas the density and feeding impact of thrips in greenhouses were higher for infested than uninfested plants. These results suggest that short-range dispersal by adults homogenises the density and feeding impact of thrips among host plants only on a small spatial scale. [source] Susceptibility of Megalurothrips sjostedti developmental stages to Metarhizium anisopliae and the effects of infection on feeding, adult fecundity, egg fertility and longevityENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2000S. Ekesi Abstract The susceptibility of immature stages of the legume flower thrips, Megalurothrips sjostedti, to the entomopathogenic fungus Metarhizium anisopliae, was investigated under laboratory conditions. The adult stage was found to be more susceptible to infection than the larval and pupal stages. Mortality at all stages was dose-dependent, with the highest concentration of 1×108 conidia ml,1 producing the highest mortality (26, 46 and 100% for larvae, pupae and adults, respectively) at 8 days post-inoculation. At the same concentration, daily pollen consumption was significantly reduced at 2 days after treatment in infected adults but more slowly in infected larvae. Fecundity, egg fertility and longevity in adults surviving infection as larvae were significantly reduced compared to the control. [source] Analysis of expressed sequence tags for Frankliniella occidentalis, the western flower thripsINSECT MOLECULAR BIOLOGY, Issue 4 2010D. Rotenberg Abstract Thrips are members of the insect order Thysanoptera and Frankliniella occidentalis (the western flower thrips) is the most economically important pest within this order. F. occidentalis is both a direct pest of crops and an efficient vector of plant viruses, including Tomato spotted wilt virus (TSWV). Despite the world-wide importance of thrips in agriculture, there is little knowledge of the F. occidentalis genome or gene functions at this time. A normalized cDNA library was constructed from first instar thrips and 13 839 expressed sequence tags (ESTs) were obtained. Our EST data assembled into 894 contigs and 11 806 singletons (12 700 nonredundant sequences). We found that 31% of these sequences had significant similarity (E, 10,10) to protein sequences in the National Center for Biotechnology Information nonredundant (nr) protein database, and 25% were functionally annotated using Blast 2GO. We identified 74 sequences with putative homology to proteins associated with insect innate immunity. Sixteen sequences had significant similarity to proteins associated with small RNA-mediated gene silencing pathways (RNA interference; RNAi), including the antiviral pathway (short interfering RNA-mediated pathway). Our EST collection provides new sequence resources for characterizing gene functions in F. occidentalis and other thrips species with regards to vital biological processes, studying the mechanism of interactions with the viruses harboured and transmitted by the vector, and identifying new insect gene-centred targets for plant disease and insect control. [source] Poor host plant quality causes omnivore to consume predator eggsJOURNAL OF ANIMAL ECOLOGY, Issue 3 2003Arne Janssen Summary 1Omnivorous arthropods are known to change their diet when host plant quality is low. Consequently, it has been suggested that decreased plant quality has a twofold negative effect on herbivore populations: (1) a decrease in growth rate of herbivores; (2) omnivores include more herbivores in their diet. We hypothesized that decreased host plant quality may also cause omnivores to feed on predators, including their own enemies. 2We tested this hypothesis, using the omnivorous western flower thrips. This species is known to feed on many plant species, but also on the eggs of another herbivore, the two-spotted spider mite. Previous research has shown that a decrease in plant quality leads to increased feeding on spider mite eggs by western flower thrips. Western flower thrips also kill the eggs of various predatory mites, including those of the specialist predator of spider mites and those of a predatory mite that attacks western flower thrips itself. 3In this paper we investigate whether thrips larvae kill predator eggs to feed on them and whether this predation depends on host plant quality. 4Larval survival as well as developmental rate increased when plant tissue of low quality (sweet pepper) was supplemented with eggs of two predatory mite species or when it was supplemented with pollen, a high-quality food type. 5Supplementing high quality leaf tissue (cucumber) with predator eggs did not lead to increased survival and developmental rate. Thrips larvae fed significantly less on predatory mite eggs when pollen was available. 6Thus, thrips larvae indeed feed on predator eggs, including those of their predator, and they feed more on predator eggs when host plants are of low quality. [source] Influence of plant species and plant growth stage on Frankliniella occidentalis pupation behaviour in greenhouse ornamentalsJOURNAL OF APPLIED ENTOMOLOGY, Issue 1 2008R. Buitenhuis Abstract The influence of plant stage and plant species on the pupation behaviour of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), was investigated in flowering and non-flowering potted chrysanthemums and mini roses. On non-flowering chrysanthemums and roses, 92,93% of the F. occidentalis pupated in the soil. On flowering roses, 87% pupated in the soil, and on flowering chrysanthemums only 60% chose the soil as a pupation site and 40% stayed on the plant. This means that, in the presence of flowers, especially complex inflorescences like chrysanthemums, a large proportion of F. occidentalis chooses stay on the plant to pupate. [source] Spatio-temporal analysis of plant pests in a greenhouse using a Bayesian approachAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2010Christine Poncet 1The present study aimed to propose a method that can improve our understanding of pest outbreaks and spatio-temporal development in greenhouse crops. 2The experiment was carried out in a greenhouse rose crop grown under integrated pest management (IPM) for 21 months. The main pests observed were powdery mildew, two-spotted spider mites and western flower thrips. A quick visual sampling method was established to provide continuous monitoring of overall crop health. 3A Bayesian inferential approach was then used to analyse temporal and spatial heterogeneity in the occurrence of pests. Interactions between pest dynamics and properties of spatial evolutions were exhibited revealing the influence of biotic and abiotic factors on crop health. 4In the context of IPM, this information could be used to improve monitoring strategies by identifying periods or locations at risk. It could also facilitate the implementation of the whole IPM procedure through the identification of key factors that have a negative impact on overall crop health. [source] Insecticide resistance management strategies against the western flower thrips, Frankliniella occidentalisPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 11 2008Pablo Bielza Abstract Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is an economically important pest of a wide range of crops grown throughout the world. Insecticide resistance has been documented in many populations of WFT. Biological and behavioural characteristics and pest management practices that promote insecticide resistance are discussed. In addition, an overview is provided of the development of insecticide resistance in F. occidentalis populations and the resistance mechanisms involved. Owing to widespread resistance to most conventional insecticides, a new approach to insecticide resistance management (IRM) of F. occidentalis is needed. The IRM strategy proposed consists of two parts. Firstly, a general strategy to minimise the use of insecticides in order to reduce selection pressure. Secondly, a strategy designed to avoid selection of resistance mechanisms, considering cross-resistance patterns and resistance mechanisms. Copyright © 2008 Society of Chemical Industry [source] Relationship between esterase activity and acrinathrin and methiocarb resistance in field populations of western flower thrips, Frankliniella occidentalis,PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 12 2006Ana C Maymó Abstract The western flower thrips, Frankliniella occidentalis (Pergande), is a serious pest in the south-east of Spain owing to its direct feeding on crops, transmission of the tomato spotted wilt virus and its very high level of resistance to insecticides. Mechanisms of resistance were examined using field populations of F. occidentalis with different susceptibilities to acrinathrin, methiocarb (selective insecticides), endosulfan, metamidophos and deltamethrin (broad-spectrum insecticides). Esterase activity towards ,-naphthyl acetate and p -nitrophenyl acetate in resistant strains was significantly higher than in the reference strain (MLFOM) for both model substrates. This higher activity was significantly correlated with acrinathrin and methiocarb resistance. Copyright © 2006 Society of Chemical Industry [source] Metabolomic analysis of host plant resistance to thrips in wild and cultivated tomatoes,PHYTOCHEMICAL ANALYSIS, Issue 1 2010Mohammad Mirnezhad Abstract Introduction , Western flower thrips (Frankliniella occidentalis) are among the most serious crop pests worldwide. Control of thrips mainly depends on pesticides, excessive use of which leads to human health risks and environmental contamination. As an alternative, we study host plant resistance to thrips. Objective , To apply nuclear magnetic resonance spectroscopy (NMR) metabolomics to study host plant resistance to thrips in wild and cultivated tomatoes. Methodology , Ten wild species and 10 cultivated tomato lines were compared. Five replicates of each species and lines were used for a thrips bioassay while another five replicates were used for the metabolomic analysis. The three most resistant and susceptible wild species, and cultivated lines, as identified by the thrips bioassay, were used for the metabolomics, performed by 1H NMR spectroscopy followed by principal component analysis. Results , Wild and cultivated tomatoes differed significantly in thrips resistance. Only wild tomatoes were thrips-resistant, among which Lycopersicon pennellii and L. hirsutum exhibited the lowest thrips damage. Their 1H NMR-based metabolomic profiles were significantly different from those of thrips-susceptible tomatoes. Thrips-resistant tomatoes contained acylsugars, which are known for their negative effect on herbivores. Conclusion , The identification of acylsugars as a resistance factor for thrips in tomato proves that NMR-based metabolomics an important tool to study plant defences, providing fundamental information for the development and realisation of herbivore resistance breeding programmes in agricultural crops. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effects of gamma irradiation on the life stages of yellow flower thrips, Frankliniella schultzei (Trybom) (Thysanoptera: Thripidae)ANNALS OF APPLIED BIOLOGY, Issue 3 2001JULIANA A YALEMAR Summary Irradiation at a minimum absorbed dose of 250 Grays (Gy) has been approved by the USDA as a quarantine treatment for certain fruits in Hawaii to control four species of tephritid fruit flies. Subsequent research must determine whether this dose is sufficient to control other quarantine pests, such as mealybugs, thrips, mites, beetles, moths, and scale insects, on other commodities with export potential that are approved for irradiation treatment for fruit flies. This study demonstrated that irradiation at 250 Gy caused non-emergence of eggs and pupae, failure of larval development, and sterility of adults of yellow flower thrips, Frankliniella schultzei (Trybom). Adults were the most resistant stage tested, with 100% mortality at 57, 36 and 30 days post-treatment for the 250, 350 and 400 Gy treatments, respectively. Untreated adults survived up to 66 days. After receiving an irradiation dose of 250 Gy, no one- to two-day old eggs hatched successfully, while 3,4-day old eggs hatched but did not develop beyond the larval stage. Of the controls, 96.0% of 1,2-day old eggs and 75.9% of the 3,4-day old eggs hatched and survived through pupation. No first or second instar larvae treated with a target dose of 250 Gy were able to pupate. When pupae were irradiated at 250 Gy, 37% emerged as adults and all were sterile compared to 88.3% emergence of controls. [source] Evaluation of existing and new insecticides including spirotetramat and pyridalyl to control Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) on peppers in QueenslandAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 2 2010Iain R Kay Abstract Insecticides are used by growers to control Frankliniella occidentalis (western flower thrips) in Australian vegetable crops. However, limited information was available on the efficacy of some insecticides used against F. occidentalis and data on new insecticides that could be included in a resistance management program were required. The efficacy of 16 insecticides in controlling F. occidentalis was tested in four small plot trials in chillies and capsicums. Spinosad, fipronil and methamidophos were effective against adults and larvae. Spirotetramat had no efficacy against adults but was very effective against larvae. Pyridalyl was moderately effective against larvae. Methidathion showed limited effectiveness. Abamectin, amorphous silica, bifenthrin, chlorpyrifos, dimethoate, emamectin benzoate, endosulfan, imidacloprid, methomyl and insecticidal soap were not effective. Laboratory bioassays on F. occidentalis collected from the field trials showed resistance to bifenthrin but not to the other insecticides tested. The trials demonstrated that some insecticides permitted for use against F. occidentalis are not effective and identified a number of insecticides, including the new ones spirotetramat and pyridalyl, that are effective and that could be used to manage the pest within a resistance management program. [source] | |||||||||||||