Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 25 for “"natural enemy"”.
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The Dynamics of Natural Enemy Resistance in Aphid Populations
… could compromise control of aphid populations by natural enemies with implications for bio-control. Sixteen pea aphid lines were genotyped and characterised for the presence of known facultative endosymbionts and the APSE bacteriophage and, of these lines, fourteen harboured at least one known …
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Host Plant and Spatial Influences on the Natural Enemy Community Structure of a Host Specific Insect Herbivore
… Here I investigate the structure of the insect natural enemy community centered on galls produced by Belonocnema treatae (Hymenoptera: Cynipidae) on the leaves of its host plants across the gall former's geographic range while controlling for spatial autocorrelation among sample sites. …
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OPTIMIZING THE BIOLOGICAL CONTROL OF INVASIVE INSECTS: EVALUATING NATURAL ENEMY HOST SPECIFICITY, PREY BEHAVIOR, AND VIBRATIONAL COMMUNICATION
… habitat. The absence of biotic factors, such as natural enemies, is one of the key aspects of their success. Therefore, introducing their natural enemies to control the phytophagous populations is an effective and sustainable management strategy for invasive insects. However, biological control …
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The role of emerging hosts in the North American emerald ash borer invasion: Implications for natural enemy-free space
… with these novel hosts for development or how natural enemies respond to EAB developing on these novel host plant species. The objectives of this study were threefold: (a) to determine the ability of Oregon ash, white fringetree, and European olive to support complete EAB larval development, …
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Sublethal effects of Bacillus thuringiensis Berliner on the diamondback moth, Plutella xylostella (L.), and its natural enemy, Cotesia plutellae Kurdjumov : implications for resistance management / by Lynne Grbin.
This research examines biological and behavioural interactions among the diamond-back moth, Plutella xylostella L. (Lepidoptera: Plutellidae), Cotesia plutellae Kurdjumov (Hymenoptera: Braconidae) and the microbial insecticide, Bacillus thuringiensis Berliner. A deterministic simulation model is …
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Influence of Selective Insecticides and Cropping System on Arthropod Natural Enemies in Soybean
Arthropod natural enemies play a key role in controlling potentially damaging pest populations in agroecosystems. An abundant and diverse natural enemy community is associated with higher yields in a variety of crops. Certain aspects of soybean production can make a field more or less amenable to a …
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Influence of living and non-living habitat complexity on arthropods in strip-tilled cabbage fields
… pests and, 2) greater abundance of important natural enemy species. Habitats with both later oat kill dates or reduced herbicide intensity contained 1) fewer herbivores with chewing feeding guilds and more specialized diet breadths and, 2) greater abundance of active hunting natural enemies. …
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The influence of native plants on arthropod population dynamics: can native plants enhance conservation biological control
… biological control aims to maintain sustainable natural enemy populations. Through increased urbanization, alien vegetation is being planted; these plants may be unacceptable hosts for herbivores. We tested the prediction that urban landscapes composed of native plants host a diverse herbivore …
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Spatial ecology of an insect host-parasitoid-virus interaction: the winter moth (Operophtera brumata) and its natural enemies in Orkney
Understanding the population dynamics of host-natural enemy interactions in spatially heterogeneous habitats may help mitigate the negative effects of environmental change. The aim of this thesis is to investigate the role of spatial processes in determining the distribution and abundance of two …
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Diapause biology, dispersal capabilities and insecticide use for Lygus lineolaris in Mid-Atlantic cotton systems
… on L. lineolaris, secondary pests, and natural enemy populations. Findings indicated that insecticides used to control L. lineolaris were successful at lowering pest populations and acephate was found to impact natural enemy populations. Plots applied with acephate experienced secondary …
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Effects of Farm Management Practices on Pest Slugs and Slug Predators in Field Crops
… crops by slugs. Conserving, and even enhancing, natural enemy populations is a desirable way to manage slug infestations because remedial control measures are limited. To better understand how cover crop usage and tillage practices affect slug and natural enemy populations, 43 Virginia fields …
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Effect of buckwheat (Fagopyrum esculentum) on the abundance and efficacy of the leafroller parasitoid (Dolichogenidea tasmanica) in a Blenheim vineyard : A dissertation submitted in the partial fulfilment of the requirements for the degree of Bachelor of Science with Honours at Lincoln University
… wasp Dolichogenidea tasmanica Cameron., a natural enemy of leafrollers. In this work, eight vine rows sown with a mid-row buckwheat strips were alternated with eight control strips (grassed) at Squire Estate vineyard, Blenheim. Two yellow 'Trappit' sticky traps per buckwheat and control row …
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The Use of Buckwheat Border Habitats to Attract Natural Enemies of Cucumber Beetles in a Cucurbit Agroecosystem
… esculentum Moench) border habitat to attract the natural enemies, Celatoria diabroticae (Shimer) and Celatoria setosa (Coquillett) (both Diptera: Tachinidae) and Chauliognathus pennsylvanicus (Deg.) (Coleoptera: Cantharidae). Five different plants were seeded in the border and buckwheat dominated. …
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Conservation biological control in a multi-strata agroforestry system
… I evaluated the response of arthropod pest and natural enemy guilds to variations in shrub layer composition and alley mowing. Shrub composition affected guilds on shrubs but had little effect on arthropods in neighboring apple trees. Pest guilds linked to apple damage were not affected by shrub …
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Agroecosystem management strategies and trophic interactions among herbivores, pathogens and predators
… strategies aiming to reduce impacts on natural enemy populations are practices that can be employed in different types of farming systems. Much of the conservative biological control efforts are focused on maintaining populations of parasitoids and predators. However, pathogens represent …
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Influence of light conditions on the dynamics of Tetranychus urticae and its control by the predatory mite Neoseiulus californicus
… questions regarding its impact on pest and natural enemy dynamics. This study investigates the impact of LED light exposure on the dynamics of the two-spotted spider mite (Tetranychus urticae) and its control by the predatory mite Neoseiulus californicus. Three light treatments were applied: …
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Assessing adaptive winter behaviors of beneficial arthropods, with a focus on the long-distance migratory ecology of Nearctic hover flies (Diptera: Syrphidae)
… the effects of field borders on arthropod natural enemy communities. Syrphid hover flies of the subfamily Syrphinae are an important group of arthropods. Adults are pollinators for a variety of crop and non-crop plant species, while larvae act as biological control agents for major crop …
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Aquatic Community Interaction Diversity and Mosquito Larvae
… First, I conducted a meta-analysis on the use of naturalenemies to control mosquito populations. Second, I developed simulation models to testthe effects of plant, herbivore, and enemy diversity, abundance and diet breadths onsampling interaction diversity in artificial communities. Third, I …
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Multitrophic Interactions in a Prairie Insect Community: Ecology, Behavior, and Conservation
… selecting for plant characters that encourage natural enemy attack."
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Population dynamics, mortality factors, and pest status of alfalfa weevil in Virginia
… pest status of alfalfa weevil and incidence of natural enemies. Fields located in the Piedmont region of the state had significantly higher alfalfa weevil pressure than those in the Shenandoah Valley and southwestern region. The dominant natural enemy of alfalfa weevil larvae was the parasitoid, …
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