To see the other types of publications on this topic, follow the link: Insect control; Swarming; Pests.
Dissertations / Theses on the topic 'Insect control; Swarming; Pests'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Insect control; Swarming; Pests.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Bouaichi, Abdelghani. "The behavioural and environmental bases of gregarization in the desert locust Schistocerca gregaria (Forskaal)." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318753.
Full text
2
Williams, Elizabeth Catherine. "Entomopathogenic nematodes as control agents of statutory insect pests." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265978.
Full text
3
Malek, Robert Nehme. "Novel Monitoring and Biological Control of Invasive Insect Pests." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/257781.
Full textAbstract:
Invasive species are alien to the ecosystem under consideration and cause economic or environmental damage or harm to human health. Two alien insects that fit this description are the brown marmorated stink bug, Halyomorpha halys and the spotted lanternfly, Lycorma delicatula. Both invaders are polyphagous pests that feed on a myriad of plant species and inflict severe crop losses. As sustainable control methods depend on the accurate monitoring of species’ invasion and involve the use of natural enemies, we addressed these two facets by exploring novel monitoring techniques and deciphering host-parasitoid interactions for improved integrated pest management. Thus, we adopted ‘BugMap’, a citizen science initiative that enables students, farmers and everyday citizens to report sightings of H. halys from Italy, with emphasis on Trentino-Alto Adige. Aside from fostering citizen participation in scientific endeavors and the enhanced literacy that ensues, BugMap helped uncover the invasion dynamics of H. halys and forecast its potential distribution in Trentino, all while coordinating technical monitoring and informing management strategies. The most promising agent currently under study for the classical biological control of H. halys is the Asian egg parasitoid Trissolcus japonicus. To assess the wasp’s potential non-target impacts, we investigated its foraging behavior in response to chemical traces ‘footprints’ deposited by its main host H. halys and by a suboptimal predatory species, the spined soldier bug, Podisus maculiventris. Wasps exhibited a ‘motivated searching’ when in contact with footprints originating from both species. However, T. japonicus arrestment was significantly stronger in response to H. halys footprints, compared with P. maculiventris, implying the presence of underlying chemical cues that shape its natural preferences. A series of GC-MS chemical analyses revealed that n-tridecane and (E)-2-decenal were more abundant in H. halys footprints and are probably the key components utilized by the wasp for short range host location. The function of the aforementioned compounds was studied, n-tridecane acted as an arrestant, prolonging T. japonicus residence time, whereas (E)-2-decenal fulfilled its presumed defensive role and repelled the wasp. These results shed new light on the chemical ecology of T. japonicus and help expand the understanding of parasitoid foraging and its implications for classical biological control. Moving to the other invader L. delicatula, an egg parasitoid Anastatus orientalis was reported attacking it at high rates in its native range in Eastern Asia and may play a key role in reducing its populations there. A series of bioassays revealed that wasps responded to footprints deposited by L. delicatula gravid females by initiating a strong searching behavior. Moreover, A. orientalis preferred to oviposit in egg masses with intact oothecae, suggesting that the host’s egg covering functions as a trigger for A. orientalis probing and oviposition. Thus, A. orientalis not only overcomes, but also reverses an important line of host structural defense for its own fitness gains. This dissertation discusses the benefits of combining citizen science with traditional monitoring, and the usefulness of decoding host-parasitoid interactions to design more efficacious management strategies of invasive insect pests.
4
Huggett, David Alan John. "Potential insect pests of the biomass crop Miscanthus." Thesis, Imperial College London, 1997. http://hdl.handle.net/10044/1/7180.
Full text
5
Bolton, Michael. "Genetic control methods for agricultural insect pests of global importance." Thesis, University of East Anglia, 2017. https://ueaeprints.uea.ac.uk/63943/.
Full textAbstract:
Insect pests of agricultural significance pose substantial risks for food security in an ever-growing global population. Conventional control measures used against these pests have had varying degrees of success and examples of pesticide resistance and offtarget effects of pesticides highlight the urgent need for the development of new, environmentally benign control methods. Deployment of ‘self-limiting’ insects is a species-specific approach that can be used to combat many species, including two major agricultural insect pests, the Medfly, Ceratitis capitata, and the Diamondback moth (DBM), Plutella xylostella. In this thesis, I used transgenic ‘self-limiting’ strains of medfly and DBM to stress-test self-limiting technology in laboratory and field scenarios. In Chapter 2, I tested the effect of larval diet composition on the penetrance of a female-specific self-limiting system in the OX3864A strain of medfly under simulated control conditions. In Chapter 3 I investigated the potential for resistance to selflimiting systems, using artificial selection for survival under a low dose of the transgene antidote, in the OX3864A medfly strain. In Chapter 4 I used the OX4319L self-limiting strain of DBM and showed that its responses to an artificial pheromone source in wind tunnel flight trials were comparable to the wild type. I also described the field dispersal characteristics of a long-term, laboratory-reared wildtype DBM strain in a mark-release-recapture trial. In Chapter 5 I demonstrated that the OX4319L DBM strain had comparable field longevity, but reduced mating competitiveness, in comparison to a wild-caught DBM strain. Finally, in Chapter 6, I discuss the broader context and address the practicalities, regulatory controls and implications of transgenic technologies for insect pest control under open field conditions.
6
Zhou, Yanmin. "Insect adhesion on rough surfaces and properties of insect repellent surfaces." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709055.
Full text
7
Hamilton, Amanda Jane. "Discovery and development of new phylloplane bio control agents to control insect pests." Thesis, University of Reading, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.701806.
Full textAbstract:
Aphids cause considerable harm to a variety of crops each year due to damage from feeding and the transmission of viruses. Effective, conventional pesticides that are authorised for use are in continuous decline; simultaneously many of the current biological pesticides fail to meet required efficiency. Increasing demands for improved food security mean that a solution for this problem is needed. Plant surfaces are well known to provide a niche for many bacteria. Some species of bacteria possess pathogenic qualities and are known to kill or incapacitate insects. Therefore there is the potential for the discovery of a direct bacterial application, or the opportunity to manipulate the crop environment in order to encourage the colonisation of these beneficial bacteria. In this project we aim to identify bacteria from plants and screen them for toxicity against aphids and their relatives. Investigations will be carried out into their host specificity, methods of pathogenicity, and potential application methods, with the hope of identifying suitable bacteria for use as a pesticide.
8
Ramos, Olgaly. "Entomopathogenic nematodes for the biological control of stored product insect pests /." Search for this dissertation online, 2005. http://wwwlib.umi.com/cr/ksu/main.
Full text
9
Green, Emily. "Development of genetic control strategies for insect pests using CRISPR/Cas9." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAJ100.
Full textAbstract:
La lutte contre les insectes nuisibles reste un défi économique, environnemental et de santé important. Le forçage génétique par CRISPR/Cas9 (FG) est un nouveau system de control génétique. Ce sont des systèmes génétiques capables d’envahir rapidement une population. Ce travail de thèse présente mes efforts pour développer des FGs chez deux espèces nuisibles, Anopheles gambiae, un vecteur majeur du paludisme, et Drosophila Suzukii, un ravageur agricole d’importance mondiale. Les objectifs de ce projet étaient de développer un FG à but d'élimination chez D. Suzukii, visant à réduire la taille de la population, et un FG à but de modification chez An. gambiae, visant à rendre les moustiques incapables de transmettre le maladie. Mes efforts pour développer un FG chez D. Suzukii n’ont pas abouti, mais les techniques et protocoles présentés ici peuvent servir de base pour de futurs travaux. Chez An. gambiae, j'ai caractérisé avec succès deux lignées transgéniques, dont l'une capable de bloquer significativement la transmission chez un modèle rongeur. Enfin, je présente mes avancées dans la mise au point d’une nouvelle stratégie, le forçage génétique indirectInsect pest control remains an important economic, environmental, and public health challenge. CRISPR/Cas9 gene drive (GD) is a novel genetic control strategy. GDs are genetic systems that can rapidly invade a population. This manuscript presents my efforts to develop gene drives in two important pest species, Anopheles gambiae, a major vector of malaria, and Drosophila suzukii, a global crop pest. The goals of this project were to develop a suppression gene drive in D. suzukii, to reduce population size, and a modification drive in An. gambiae, to reduce malaria transmission. While I was unable to produce a functional gene drive in D. suzukii, the efforts and protocols presented here can serve as a baseline for future work in this economically important crop pest. In An. gambiae, I successfully characterized two transgenic lines, one of which significantly blocks malaria transmission to a rodent model. Finally, I present my efforts to engineer a new modification gene drive strategy, indirect gene drive
10
Ukeh, Donald A. "The identification and use of semiochemicals for the control of the maize weevil, Sitophilus zeamais (Motschulsky) in Nigeria." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2008. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=25167.
Full text
11
Greenfield, Bethany Patricia Jane. "Metarhizium pathogenesis of mosquito larvae." Thesis, Swansea University, 2014. https://cronfa.swan.ac.uk/Record/cronfa42819.
Full text
12
Salloum, Gregory Stewart. "Insect growth inhibitors from asteraceous plant extracts." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26529.
Full textAbstract:
Petrol and ethanolic extracts of six asteraceous weeds were added to artificial diet and screened for inhibition of larval growth on variegated cutworm, Peridroma saucia (Hbn.). Petrol and ethanolic extracts of Artemisia tridentata and Chamomilla suaveolens and ethanolic extracts of Chrysothamnus nauseosus and Centaurea diffusa were highly inhibitory at five times the naturally occurring concentrations. The two C. suaveolens extracts and the ethanol extract of A. tridentata were active at the natural concentration (100%) and were further examined at 20, 40, 60, and 80% of this level. Inhibition of larval growth was directly related to concentration for each of the three extracts tested. EC₅₀'S (effective concentration to inhibit growth by 50% relative to controls) for the three extracts were 36-42% of the naturally occurring level in the plants.
Nutritional indices were calculated for second instar P. saucia feeding on the active ethanolic A. tridentata extract and the petrol extract from C. suaveolens. The relative growth rate (RGR) of P. saucia larvae fed the ethanolic extract of A. tridentata in artificial diet was significantly lower than that in larvae fed diet with the petrol extract of C. suaveolens and larvae on control diet. Dietary utilization was significantly lower for larvae fed the A. tridentata extract. Results of a field trial indicated that a single treatment of A. tridentata extract at the equivalent of 0.2 g/ml could protect cabbage significantly better than the carrier solvent (30% aq ethanol) or distilled water as measured by a visual damage estimate. An insecticide standard, deltamethrin (17.9 µg/1 with 0.4% Superspred TM ), suppressed pest damage significantly better than the A. tridentata-extract treatment.
A residual oviposition deterrency to Pieris rapae was found in the field results. Caged experiments in the laboratory confirmed the contact oviposition deterrency of the A. tridentata extract at 0.2 g/ml. Offspring of field-collected P. saucia larvae grew 2.5-fold heavier than larvae from the laboratory colony. However, diet with the A. tridentata extract inhibited both field-collected and laboratory reared saucia larvae equally when compared to their respective controls fed untreated diet. In summary, these results indicate the potential benefit of using specific unrefined plant extracts for growth inhibitors and oviposition deterrents against insect pests. The contribution of individual phytochemicals in the A. tridentata ethanolic extract to growth inhibition or oviposition deterrency is currently speculative.Land and Food Systems, Faculty of
Graduate
13
Mazahery-Laghab, Hojjatollah. "Endogenous resistance to insect pests in alfalfa : engineering for enhanced resistance." Thesis, Durham University, 1997. http://etheses.dur.ac.uk/4695/.
Full textAbstract:
Alfalfa (Medicago sativa) is a valuable forage crop grown throughout the World. While the crop is resistant to attack by many insect pests, it is subject to potentially severe losses through the action of several specific pests, which are adapted to alfalfa as a host. The most economically damaging of these pests is the alfalfa weevil, Hypera postica. This thesis investigates the endogenous defences of alfalfa against insects, which are responsible for its resistance to non-pest species, and develops a strategy for increasing the resistance of alfalfa towards pest species, specifically alfalfa weevil. The role of saponins in the resistance of alfalfa towards non-pest species has been investigated by using successive insect bioassays, carried out with extracts, mixtures of compounds, and purified compounds, to identify which compounds present in alfalfa tissues are responsible for toxicity towards insects. Crude saponin extracts, in 80% methanol, from alfalfa seedling tissues were bioassayed against the cowpea seed weevil, Callosobruchus maculatus. Both extracts from shoot and root tissues caused larval mortality and delayed development when incorporated into an artificial diet at levels comparable to those found in alfalfa, but lower levels of root saponin extracts showed probiotic effects, whereas lower levels of shoot saponins were still toxic. Hydrolysis of the saponins present in these extracts decreased their toxicity. Purified saponin mixtures were prepared by butanol partition and ether precipitation, and were bioassayed against potato aphid (Aulacorthum solani) in a liquid artificial diet, which allowed quantitative effects to be accurately assayed. Shoot saponins showed a concentration-dependent toxic effect, decreasing survival over an initial 5 day period, decreasing growth, and inhibiting fecundity (measured by nymph production) in these insects. Alfalfa root saponins showed no deleterious effects below a threshold level, but caused complete mortality above this level. The alfalfa saponin mixtures were separated into fractions by chromatography on a reverse phase column. Bioassays showed that the toxicity towards potato was associated only with fractions containing saponins, and that fractions containing a component identified as soyasaponin I were more toxic to the aphids than others. Finally, two saponins purified from alfalfa, soyasaponin I and medicoside A, were assayed. These assays showed that soyasaponin was consistently more toxic in effects on mortality, growth and fecundity. It was concluded that alfalfa saponins, and in particular soyasaponin I, were major factors in the resistance of alfalfa towards potato aphid, and other insects. A saponin mixture from another species, sugar beet {Beta vulgaris) was also toxic to aphids, supporting the view that saponins have a general role in resistance to insects. Inhibition of insect digestive proteolysis by expression of a foreign protein protease inhibitor was selected as a strategy to protect transgenic alfalfa against alfalfa weevil. The major protease activity in larvae of this msect was shown to be due to cysteine proteases, which could be inhibited by cystatins. Rice cystatin was produced in large quantity using a recombinant protein expression system in E. coli for use in a "proving" experiment. Incorporation of the rice cystatin into an alfalfa weevil larvae artificial diet decreased survival, showing that this approach was feasible.
14
Adedipe, Folukemi Ebunoluwa. "Investigation of ecological behavior of two Coccinellidae beetle adults for biological control." Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10491.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 2009.Title from document title page. Document formatted into pages; contains vii, 60 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
15
Scholtz, Anna J. "Evaluation of the large-scale trapping of blowflies (Lucilia spp.) for an integrated pest management program : the lucitrap." Thesis, Port Elizabeth Technikon, 2003. http://hdl.handle.net/10948/126.
Full textAbstract:
The results presented in this dissertation have been partially presented at scientific meetings. Chapter 2 is an exact copy of the technical contents of a paper submitted to a scientific journal. The format of this paper however has been changed to comply with the format used in this dissertation. The results of this paper were partially presented at the 36th National Congress of the South African Society of Animal Science, 5 – 8 April 1998 held in Stellenbosch. In this chapter errors occurred in the execution of the trial, but these were corrected in the follow-up trial after consulting with the manufacturers. It is discussed in the paper. Results of chapter 3 were partially presented at the 5th International Sheep Veterinary Congress 21 – 25 January 2001 held in Stellenbosch and at an International Congress (The FLICS (Flystrike & Lice IPM Control Strategies) Conference, 25 – 27 June 2001, Launceston) in Tasmania by Mr. S.W.P. Cloete in 2001. The updated results are given in this chapter. The results of chapter 4 were presented at a combined congress between the Grasslands and the Animal Production Societies of South Africa (The GSSA/SASAS Joint Congress 2002. 13 – 16 May) in Christiana in 2002. The results in this chapter represent the same experimental period as was reported upon at that congress, but additional statistical analyses were executed on the same data set. Copies of the abstracts of the contributions to these meetings are attached in chapter 6. The major objective of this study initially was to evaluate the Lucitrap® system under South African conditions. During the experimental period I had an opportunity to visit Australia and meet many role players. It came under my attention that the control of the blowfly is a rather complex problem with many facets. A current issue worldwide on the use of chemicals as a control method against insects and its hazardous influence on the environment is forcing producers to minimize chemical residues in textiles and other agricultural products. An Integrated Pest Management (IPM) approach seems to be the only option. This study has been executed to try and understand some aspects of the blowfly problem for future application in such a blowfly control program.
16
Rust, Nico. "The development of a commercial production process for p-menthane-3,8-diol." Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/d1018273.
Full textAbstract:
The synthesis of p-menthane-3,8-diol via the acid-catalyzed cyclization of citronellal in a dilute aqueous sulphuric acid medium was investigated using conventional batch and continuous systems in order to develop a commercial production process for said p-menthane-3,8-diol (PMD). The batch studies conducted during the first part of this study showed that the formation of PMD from citronellal occurs via an intra-molecular Prins reaction that results in the formation of both the desired PMD product, as well as the partially hydrated isopulegol. It was shown that the formationof the by- product, PMD-acetal, results from the reaction between an intermediate, 5-methyl-2- isopropylcyclohexanol, and the citronellal starting material, and not from the reaction between PMD and citronellal as previously reported. Kinetic studies confirmed the existence of a complicated kinetic model. The formation of PMD from citronellal displayed typical pseudo first order kinetics up to conversions of 70 after which the kinetic model becomes complicated as the result of the establishment of quasi equilibrium reactions between PMD and isopulegol (dehydration of PMD and hydration of isopulegol) and between PMD the PMD-acetal, both systems being acid catalysed. The PMD-acetal formation reaction appears to be second order with respect to PMD. Scale-up studies of the batch process to 30L and 50L scales showed that it would be extremely difficult to limit the level of PMD-acetal formation below the desired level of 1 percent, even if citronellal conversions are restricted to about 50 percent. During studies conducted on a commercially availablemicro-structured organic synthesis plant (OSP) it was shown that it is possible to perform the PMD reaction as a continuous process. The results obtained showed that the use of a micro-mixer such as the caterpillar micro-mixer did not provide enough residence time in order for desirable conversions (- 40 percent) to be obtained. By combining themicro-mixer with delay-loops of different thicknesses and lengths, and using increasing reaction temperatures, it was shown that the conversion of citronellal could be improved to some extent, but compared poorly to the expected conversions for a well-stirred batch reactor. By packing selected delay loops with inert SiC particles, improved mass transfer was observed between the organic and aqueous phases as reflected in the increased conversion of citronellal. Using the observations that were made during the use of the OSP, a continuous-flow, tubular reactor system was designed and constructed. Advanced statistical techniques were used to investigate the effect of variables such as temperature, acid concentration, reactor length, flow rate and the organic to aqueous ratio on the rate and selectivity of the reaction. Mathematical models were derived for citronellal conversion, yield of PMD and yield of PMD- acetals, and used to predict the concentrations of citronellal, PMD and PMD-acetals at set experimental conditions. The results obtained showed that it was possible to obtain a product which approached desired specifications.Downstream processing of the PMD reaction mixture as it exits the reactor requires phase separation and neutralization of the acid catalyst solution, followed by further work-up to recover unreacted starting material and intermediates for recycle back to the synthesis reactor, followed by purification of crude PMD to the desired specification. The study showed that neutralization, prior or after phase separation, does not affect the selectivity of the PMD to such a great extent, but does influence the relative conversion due to extended contact of the catalyst with the organic phase after the reaction is terminated. Recovery of unreacted citronellal and isopulegol could be achieved by a simple vacuum evaporation step, which may either be carried out in a batch manner using traditional distillation equipment, or in a continuous process using wiped-film (short path) techniques. It was also shown that selective crystallization of PMD from the crude product mixture by addition of a solvent, such as heptanes or hexane proved to be the best way of achieving the desired product specification.
17
Turner, David Edward. "Reduced dose rate insecticide use in cereals : effects on insect pests and predators." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296165.
Full text
18
Alm, Steven Robert. "Monitoring and control of Conotrachelus nenuphar (Herbst) and Glischrochilus quadrisignatus (Say) : (Coleoptera--curculionidae, nitidulidae) /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487262825075913.
Full text
19
Schirocki, Anke Gabriele. "The effect of temperature on invasion and pathogencity of entomopathogenic nematodes (nematoda: Rhabditida) to larvae of Galleria mellonella and Otiorhynchus sulcatus." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308061.
Full text
20
Bourchier, Robert S. "Development of traps for adult Glischrochilus quadrisignatus (Say) (Coleoptera:Nitidulidae) and investigation of olfactory responses to volatile components of corn, raspberry and tomato." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66170.
Full text
21
Rogers, Richard E. L. "Insect and mite monitoring in commercial apple orchards in Nova Scotia (1979-1985)." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65368.
Full text
22
Warner, Douglas James. "The potential of carabidae in the control of insect pests of winter oilseed rape." Thesis, University of Hertfordshire, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366035.
Full text
23
Scott, Corraine Athol. "Leguminous and graminaceous cover crops for the control of insect pests in organic squash." [Gainesville, Fla.] : University of Florida, 2008. http://purl.fcla.edu/fcla/etd/UFE0022711.
Full text
24
Helvering, Leah M. "Cloning of genes encoding larvicidal proteins from Bacillus thuringiensis subsp. israelensis into the cyanobacterial hybrid vector, pTNTV." Virtual Press, 1989. http://liblink.bsu.edu/uhtbin/catkey/562782.
Full textAbstract:
Bacillus thuringiensis subsp. isrealensis (B.t.i.) produces a crystalline endotoxin specific for some larvae of mosquitoes that are vectors of the malaria parasite and other infectious diseases. Fragments were obtained from the 108 kb plasmid from B.t.i. strain 4Q2 which encodes several proteins comprising the delta-endotoxin. These DNA fragments were inserted into the hybrid cyanobacterial cloning vector, pTNTV, downstream from its powerful lambda promoter, and the chimaeras were transformed into Escherichia coli. Ampicillin resistant transformants were screened with radioactively labelled oligonucleotides whose sequences were determined from the published sequences of the B.t.i. 130 kDa polypeptide. Clones showing hybridization were used in bioassays to determine their level of toxicity to the fourth instar larvae of the Aedes aegypti mosquito. Twelve clones were found that demonstrated toxicity which was statistically significantly greater than that observed in controls. Plasmid DNA from some of these clones was isolated, cut with restriction endonucleases, and viewed through agarose gel electrophoresis to confirm that B.t.i. fragments had been inserted into the vector. Future work will investigate the expression of these cloned toxin genes in transformable cyanobacteria and will determine their subsequent activity against the fourth instar larvae of Aedes aegypti and Anopheles quadrimaculatus.Department of Biology
25
Perera, Mallawa Thanthrie Mudiyanselage D. Renuka. "Response of pests of brassicae and their parasitoids to synthetic and natural feeding deterrents." Thesis, University of Aberdeen, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287701.
Full textAbstract:
Antifeedants and growth regulators have potential as alternatives to conventional methods of insect pest control. As with conventional chemicals it is important to consider their effects on natural enemies of the pests. The aim of this project was to determine whether the bitter-tasting synthetic chemical denatonium benzoate as an antifeedant and compare with neem derivatives. Other aims were to investigate their effect on parasitoids and the field infestation of cabbage pests. Denatonium benzoate is systemic and had no contact effect but acted as an antifeedant on a generalist sap feeder Myzus persicae and reduced the survival, fecundity, and lifespan. Neem derivatives, Azatin EC and Pestistat R were more effective of which Azatin EC was the most effective. Antifeedants further reduced the fecundity and survival when parasitized with its parasitoid, Aphidius matricariae and neem derivatives had adverse effects on both aphid and the parasitoid. Denatonium benzoate and Pestistat R with a specialist leaf feeder, Pieris brassicae and all antifeedants with Plutella xylostella (generalist leaf feeder) and Chrysodeixis eriosoma (specialist brassica leaf feeder) reduced the leaf area consumed and it was inversely proportional to the concentration. The highest leaf area consumption was in denatonium benzoate and the lowest in Pestistat R. Higher azadirachtin concentrations were detrimental but denatonium benzoate was safer to the larval parasitoid, Cotesia plutellae. Denatonium benzoate and Azatin EC reduced field infestation of M. persicae, P. xylostella and C. eriosoma in Peradeniya, Sri Lanka and Azatin EC was the most effective. Denatonium benzoate acts as an antifeedant against cabbage pests and safer towards parasitoids hence can be used in integrated pest management programmes. Neem derivatives are comparatively more effective on pests but harmful to parasitoids. Denatonium benzoate and Azatin EC effectively reduced the pest infestation under field conditions.
26
Nepgen, Eugene Stephan. "A study on the application technology of the sterile insect technique, with focus on false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), a pest of citrus in South Africa." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013199.
Full textAbstract:
False codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is considered the most important indigenous pest of citrus in southern Africa. Major concerns such as progressive insecticidal resistance, the negative impact of insecticides on the environment, as well as the influence of consumers opposed to chemical residues on fruit, created opportunities for biological control methods such as Sterile Insect Technology (SIT). This technology is now established in the Western and Eastern Cape provinces of South Africa as an effective, sustainable alternative to conventional FCM control methods. Due to the prevalence of the pest in all citrus producing areas of South Africa, potential for SIT to expand is enormous. Success of an SIT programme is highly dependent on efficient application of the technology to achieve its objectives in a timeous manner. The aim of this study was to advance the application of SIT for control of FCM on citrus in South Africa, by investigating the effect of certain critical stages in the process. The effect of long-distance transportation on fitness of irradiated FCM was determined, showing reduced performance with cold-immobilized transport. A significant decrease in flight ability and longevity of irradiated FCM was found, although critically, realized fecundity was not affected. The effect of two different insecticides in the pyrethroid and organophosphate chemical groups were investigated for their residual effect on mortality of released irradiated FCM, to determine if these pest control programmes could be integrated. Both chlorpyrifos and tau-fluvalinate were effective in killing irradiated FCM for a number of days after application, after which degradation of the active ingredient rendered it harmless. This effect was found to be similar for irradiated and non-irradiated males, consequently ratios of sterile : wild male FCM should be retained regardless of whether sprays are applied or not. The modes for release of sterile FCM in an SIT programme were investigated. Efficacy of ground and aerial release platforms were tested by evaluating the recovery of released irradiated male FCM in these orchards. More irradiated FCM were recovered in orchards released from the ground compared to air. However, an economic analysis of both methods shows application of irradiated insects over a large geographical area is more cost-effective by air. Depending on the terrain and size of the target area, a combination of both methods is ideal for application of SIT for control of FCM in citrus. Development of application technology for advance of the programme is discussed and recommendations for future research and development are offered.
27
Wagenaar, Gideon Daniel. "Dispersal of sterile false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), for a sterile insect technique programme on citrus." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/4977.
Full textAbstract:
The false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), is an important pest of citrus in South Africa and challenging to manage due to its inconspicuous nature. An effective method currently being employed for the area-wide suppression of the FCM is the Sterile Insect Technique (SIT) and the effective dispersal of sterile moths is very important for success with SIT. This study was conducted in the Addo area of the Sundays River Valley (Eastern Cape) where the programme is commercially used. In this study, sterile male moths were released in different orchards on a citrus farm, and in nearby veld at different times of the year, and their dispersal was monitored through the use of pheromone traps. Various climatic factors were monitored. This provided insight into the local dispersal of sterile male FCM adults in response to abiotic cues (particularly climatic factors). The movement of the FCM in four citrus cultivars, namely lemons, navel and Valencia oranges and mandarins and in the nearby veld (open field), was determined at six different stages of the year. Results clearly indicated that sterile FCM movement is concentrated within citrus orchards, as very few moths were trapped beyond 30 m from the release point, particularly in navel and Valencia orchards. Of the climatic factors measured, minimum and maximum temperatures had the most significant influence on FCM dispersal, and based on the results, various recommendations are made for the releases of sterile FCM in an area-wide SIT management programmes on citrus. A better understanding of the dispersal capabilities of the FCM in an agricultural system, under different conditions and at different times of the year, is invaluable not only in improving release strategies in an SIT programme but in planning future control strategies against the FCM.
28
Er, Mehmet Kubilay. "Studies on the microbial control of pastureland leatherjackets (Tipula spp. Tipulidae: Diptera)." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327215.
Full text
29
Tremblay, Annie C. "The role of birds as predators and potential biocontrol agents of insect pests in corn fields." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ50898.pdf.
Full text
30
Palumbo, J. C., C. H. Jr Mullis, and F. J. Reyes. "Comparative Effectiveness of Bacillus thuringiensis Formulations Against Lepidopterous Pests of Fall Lettuce." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/214515.
Full textAbstract:
A field study was conducted at Yuma in 1991 to examine the relative effectiveness of several formulations of Bacillus thuringiensis on beet armyworm and cabbage looper on seedling and pre-cupping lettuce. Several applications were made before and after thinning. Results of the study suggest that most formulations are capable of controlling small larvae. However, because of the inherent variation in beet armyworm dispersion, it was difficult to statistically attribute differences in pest levels due to insecticide efficacy.
31
Hicks, Teri Ann. "Expression of the bacillus thuringiensis var. israelensis 130kDa delta-endotoxin and the firely luciferase reporter gene in escherichia coli." Virtual Press, 1991. http://liblink.bsu.edu/uhtbin/catkey/770955.
Full textAbstract:
The use of the larvacidal delta-endotoxin of the sporeforming bacterium Bacillus thuringiensis var. israelensis has been examined as a promising means to control insects that carry diseases such as malaria. An ultimate goal of this project was to genetically engineer both E. coli and the cyanobacterium Synechococcus PCC 7942 to express high levels of this delta-endotoxin and to construct the recombinant to carry a gene which would allow for monitoring of recombinants in the field. Previous research performed by a member of our laboratory involved cloning the gene fragment encoding the delta-endotoxin into a hybrid plasmid yielding recombinant E. coli clones which were toxic to mosquito larvae. Unfortunately, upon further examination of these recombinants using agarose gel electrophoresis and mosquitocidal assays, the clones were found to be unstable and lost their toxin encoding genes readily. Furthermore, cloning of the stabilizing parB locus into one of the recombinant plasmids did not enhance segregational stability as had been shown with some plasmids in E. coli. In another approach oligonucleotide primers were constructed which flanked the 130 kDa toxin gene but excluded a transposon-likesequence postulated to contribute to instability. These primers were used in the polymerase chain reaction in order to amplify this smaller DNA fragment for cloning experiments. Only a small quantity of primers were made and amplification of the DNA was not achieved prior to depletion of the primers. Future work will involve synthesizing new primers to be used for amplification and cloning of the B.t.i. toxin gene.In order to construct a traceable recombinant, the luciferase reporter gene (Luc) had been previously cloned into a hybrid plasmid that was capable of transforming both E. coli and the cyanobacterium Synechococcus PCC 7942. The new construction was then transformed into E. coli, to yield a pool of uncharacterized recombinants. In the present work, I determined that the luciferase enzyme was being expressed in the E. coli recombinants in the presence of the substrate luciferin. Initially, bioluminescence of these E. coli clones was detected by using OG-1 film which fogs in the presence of light. In order to quantify expression of the clones, lysates of the E. coli recombinants were also examined using a luminometer. Comparisons of bioluminescence were made between lysates with the parent E. coli plasmid harboring the luciferase gene and recombinants in which the Luc gene was placed downstream of the powerful rightward lambda promoter. Luminometer readings indicated that luciferase expression was enhanced six fold (from 2.0 X 10-6 to 3.0 X 10-5 by units/cell) in the recombinant plasmid. Plasmid DNA was isolated from the two luciferase expressing E. coli clones. Recombinants were obtained as determined by agarose gel electrophoresis examination of the plasmid DNA. This recombinant DNA was used to transform Synechococcus PCC 7942. However, because enzyme releasing methods were unsuccessful for the more rigid Synechococcus PCC 7942, the level of expression of the Luc gene could not be determined by either method mentioned above. Apparently, the methods used either failed to lyse the cells or they were too harsh and inactivated the enzyme. Future endeavors will involve the use of a French press to more gently lyse the cells so that the level of expression can be determined.Department of Biology
32
Afun, Jakpasu Victor Kofi. "The role of weeds in the natural control of upland rice insect pests in Cote d'Ivoire, West Africa." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268021.
Full text
33
Mathewson, Johanna. "Die insekplaagkompleks op sitrus te Vaalharts." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51706.
Full textAbstract:
Thesis (MSc)--Stellenbosch University, 2000.Full text to be digitised and attached to bibliographic record.
ENGLISH ABSTRACT: The cultivation of citrus in the Vaalharts region is a fairly recent development. With the introduction of this crop, an insect pest complex has also developed in this region. The presence of these pests was studied in eleven orchards, planted with three citrus cultivars and of varying ages, distributed in the 300 square kilometer cultivation area. Each orchard was inspected for the presence of pests by making use of two weekly sampling techniques. Ten of the most important insect pests of citrus in the Vaalharts region are briefly described by refering to their general appearance, life cycles, feeding and pest status and economic threshold. For every pest various control options, including operational systems, crop cultivation, biological and chemical control, are discussed and, where applicable, illustrated by means of graphic presentations. The seasonal presence of the cirtrus pests in the Vaalharts region is tabulated and discussed individually. With these details as background, an insect pest management programme for citrus in the Vaalharts region is compiled.
AFRIKAANSE OPSOMMING: Die verbouing van sitrus in die Vaalhartsgebied is 'n redelik onlangse ontwikkeling. Gepaard met die nuwe gewas het daar ook 'n insekplaagkompleks in die gebied ontstaan. Die voorkoms van die plae is in elt .boorde, beplant met drie sitruskultivars en van verskillende ouderdomme, verspreid in die 300 vierkante kilometer verbouingsareaal, bestudeer. Elk van die boorde is weekliks ondersoek vir die aanwesigheid van plae deur van twee moniteringstegnieke gebruik te maak. Die tien belangrikste insekplae van sitrus in die Vaalhartsgebied word kortliks beskryf deur na hulle algemene voorkoms, lewenssiklus, voeding en plaagstatus en ekonomiese drempelwaardes asook die moniteringsmetodes wat gebruik is, te verwys. Vir elke plaag word beheeropsies, wat operasionele stelsels, gewasverbouing, bloloqlese en chemiese beheer insluit, bespreek wat, waar toepaslik, aan die hand van grafiese voorstellings gemustreer word. Die seisoenale aanwesigheid van die sitrusplae word in 'n tabel aangedui en individueel bespreek. Met die gegewens as agtergrond is 'n insekplaagbestuurprogram vir sitrus in die Vaalhartsgebied opgestel.
34
Powell, Peggy K. "Penetration and permanence of an organophosphate and a pyrethroid in structural wood for insect control." Diss., Virginia Tech, 1990. http://hdl.handle.net/10919/37743.
Full text
35
Smith, Susan Margaret. "The use of the entomopathogenic fungus Beauveria bassiana (bals.) vuill. for control of insect pests of stored maize." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390614.
Full text
36
Petrova, Adelina Simeonova. "Investigating the role of insect saliva in the plant-insect interaction as a basis for development of novel methodologies for control of homopteran pests of cereals." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.577152.
Full textAbstract:
Phloem feeding insects (aphids, hoppers) are an important group of pests. They cause damage to their host plant not only by removing nutrients, but also more importantly by transmitting viral diseases. To date, there are no effective long-term control methods for managing the populations of these pests. To address this problem recent research has focused on studying endogenous defence mechanisms, with the aim of their future exploitation in crop protection. This project has studied both sides of plant-insect interactions (plant responses and insect means for invasion), using as a model system Oryza sativa (rice) as the host plant and Nilaparvata lugens (Brown planthopper) as the insect pest. The overall objective of the project was to investigate the molecular and biochemical nature of the 0. sativa - N. lugens interaction as a means of providing the basis for developing novel strategies for control of homopteran pests. For this purpose, insect feeding as the major determinant of host plant responses was studied with particular emphasis on the role of insect saliva, since recent studies on chewing insects have demonstrated that saliva is the main factor modulating host responses. Studying saliva from phloem feeding insects is extremely difficult and to date no salivary compounds from this insect order have been identified within host plants. Hydrogen peroxide (HzOz) is a part of the Reactive Oxygen Species (ROS) system, which includes superoxide (Oy), and hydroxyl radical (OH) as well. Several roles for HzOz have been assigned, such as signalling, cell wall modification and direct toxicity to pathogens and insects. Catalase is the main enzyme responsible for decomposition of hydrogen peroxide (HzOz). Using PCR with degenerate primers, a catalase cDNA (Kat-1) from Nilaparvata lugens salivary glands was identified. Kat-1 transcript abundance was higher in the gut than in salivary glands. Recombinant catalase (~57 kDa) was produced in E. coli, purified and used to produce antibodies in rats. lmmunodetection analysis indicated that there are three possible catalases with molecular masses of ~ 57 kDa, ~70 kDa and ~1 00 kDa in the salivary glands but only one ~57 kDa in the gut. A ~70 kDa immunoreactive protein was detected as well in infested host tissue from the resistant variety, suggesting that catalase is secreted from saliva into host plant tissue. Thus, the role of Nilaparvata lugens salivary catalase may be disruption of signalling and detoxification as well as conditioning of the host cells. Production of ROS occurs under both stressed and non-stressed conditions and ROS concentrations are modulated by enzymatic and non-enzymatic components within the antioxidant system. Key enzymes from the antioxidant system include superoxide dismutase (SOD; EC 1.15.1.1), catalases (CAT; EC 1.11.1.6), ascorbate peroxidases (AsPOX; EC 1.11.1.11), glutathione reductase (GR; EC 1.6.4.2) and class III peroxidases (POX; EC 1.11.1.7). The effects of Nilaparvata lugens infestation and saliva on the antioxidant enzyme system in resistant and susceptible varieties were studied by assaying enzyme activity. Temporal and spatial analysis indicated different patterns of enzyme activation in susceptible and resistant host varieties, suggesting that the antioxidant enzyme system is controlled differently in the two rice varieties. At systemic level during infestation, increase of the HzOz-detoxifying system activity (SOD, CAT and AsPOX) was demonstrated only in the resistant variety. Further, saliva induced GR and AsPOX activity in the resistant variety only. These two enzymes are part of the AA-GSH (Ascorbate- Glutathione) cycle, the most important HzOz-detoxifying system in the chloroplasts, peroxisomes and mitochondria. At the mRNA level, there were local differential effects of infestation and saliva in the susceptible and resistant varieties on the expression of SOD and CatA genes. Variation in the expression patterns of genes coding for different forms of SOD, as well as CatA, was demonstrated only in the susceptible variety. Systemic expression of Nilaparvata lugens saliva-responsive genes was studied through subtractive hybridisation and Real Time RT-PCR confirmed the differential expression of several genes. Functional analyses indicated that Nilaparvata lugens saliva altered expression of genes involved In primary metabolism, signalling, transport, translation and regulation and with unknown functions. More than one third of up-regulated genes were implicated in senescence, including biosynthesis of exported amino acids and transport.
37
Jech, L. E., and S. H. Husman. "Correlation between Early Season Insecticide Control of Pink Bollworm and Other Pests and Subsequent Whitefly Applications near Gila Bend, AZ, 1997." College of Agriculture, University of Arizona (Tucson, AZ), 1998. http://hdl.handle.net/10150/210360.
Full textAbstract:
Cotton pesticide application histories in the Gila Basin were followed from 27 April through 20 September. The main interest was the effect of early season applications to control pink bollworm, Pectinophora gossypiella, and other pests on subsequent whitefly applications. Categories explored include, transgenic and non transgenic cotton, planting dates, and location within the valley. Regression analysis shows a significant effect due to the early season control for either P. gossypiella, or other pests (P > 0.009) but lower for them together (P > 0.026). Early applications for either PBW or other pest resulted in increased application for whitefly.
38
Smith, Ethan A. "Is everything connected? following the predators, pests, and plants within a no-till, western Montana agroecosystem /." CONNECT TO THIS TITLE ONLINE, 2006. http://etd.lib.umt.edu/theses/available/etd-12212006-142245/.
Full text
39
Pryke, James Stephen. "Source and identity of insect contaminants in export consignments of table grapes." Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1169.
Full text
40
Martel, John W. "Development of Semiochemical-Based Strategies for Management of Colorado Potato Beetle, Leptinotarsa decemlineata (Say)." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/MartelJW2004.pdf.
Full text
41
Ahmed, Mohamed Mudathir Mohamed. "Studies on the control of insect pests in vegetables (okra, tomato, and onion) in Sudan with special reference to neem preparations." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=961140771.
Full text
42
Scott, Ian M. "The efficacy and mode of action of Piper (Piperaceae) botanical insecticide for control of insect pests of the home and garden." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/29161.
Full textAbstract:
The present study highlights the practical application of a Piper-based botanical insecticide for controlling insect pests of the home and garden in urban areas in eastern Canada and northeastern North America. Biopesticides, including botanicals, can offer a safe and effective alternative to conventional insecticides for controlling major insect pests within an IPM program. Secondary compounds from the Piperaceae family, specifically the abundant isobutyl amides and lignans, have shown promise for insecticidal applications.
A method for extraction and HPLC-MS analysis of Piper spp. was developed in order to allow quick and accurate measure of piperamide levels in P. nigrum, P. tuberculatum, West African Guinea pepper, P. guineense Schum and Thonn, and in less recognized species from Central America. Extraction of leaf and peppercorn material with 50:50 ethyl acetate and water provided a greater than 80% recovery of spiked piperine. HPLC analysis using a binary gradient of acetonitrile and water provided a clean separation of the major amide peaks between 5 and 12 min. The use of APCI-MS improved the detection limit 10 fold below the 2-ng limit of the HPLC-DAD method.
Extracts from P. nigrum, P. guineense and P. tuberculatum were tested for efficacy against insects from five orders. Among the insect pests tested, the most sensitive species were, in order of increasing lethal concentration: Eastern tent caterpillar, Malacosoma americanum F. < European pine sawfly larvae, Neodiprion sertifer Geoffroy < spindle ermine moth larvae, Yponomeuta cagnagella Hubner < Viburnum leaf beetle larvae, Pyrrhalta viburni Paykull < stripped cucumber beetle adult, Acalymma vittatum Fabrcius < Colorado potato beetle adult, Leptinotarsa decemlineata (Say) < Japanese beetle adult, Popillia japonica Newman < hairy chinch bug, Blissus leucopterus hirtus Montandon. Greenhouse trials revealed that the pepper formulations also had a repellent activity thus protecting plant leaves from: (1) herbivory by lily leaf beetles, Lilioceris lilii (Scopoli) adults and larvae, and striped cucumber beetle, Acalymma vittatum F. adults and (2) oviposition by European corn borer, Ostrina nubilalis (Hubner).
When an insecticide resistant strain of potato beetle larvae was tested with the P. tuberculatum extract, there was less than a two fold tolerance ratio compared to the 22-fold tolerance ratio to cypermethrin, a pyrethroid. An in vitro polysubstrate monoxygenase (PSMO) enzyme assay, using the substrate methoxyresorufin O-demethylation (MROD), determined that piperine, is responsible for inhibition of that specific enzyme. A subsequent toxicokinetic study determined that piperine is quickly eliminated from the exoskeleton (t1/2 = 16.5 h) and hemolymph (t 1/2 = 12 h) of the adult American cockroach Periplaneta americana L. after a topical application. (Abstract shortened by UMI.)
43
Chang, Gary C. "Ecological interaction among natural enemies and its consequences for biological control /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/5205.
Full text
44
Hepburn, Colleen. "Composition and phenology of insect pests of Capsicum (Solanaceae) cultivated in the Makana District, Eastern Cape Province, South Africa." Thesis, Rhodes University, 2008. http://hdl.handle.net/10962/d1005339.
Full textAbstract:
Capsicum baccatum var. pendulum was first grown in the Makana District in 2005. Extremely little was known about best practices for cultivation or the insects and diseases associated with the crop in this area. The study was conducted during the second year of production, November 2005 and November 2006, in an attempt to identify the composition and phenology of insects occurring on C. baccatum. In the more rural parts of the Eastern Cape, and more particularly in Grahamstown, there are very few industries. With the advent of this new agricultural venture, a processing factory has been opened in Grahamstown creating more than 600 seasonal jobs in the factory and 1000 seasonal jobs on farms for local people. This business enterprise has not only brought about the creation of jobs, but also training and skills development and empowerment, generating much-needed income in this area. An extensive literature review yielded limited information on insect pests associated with Capsicum. Data from a pilot sampling trial undertaken were statistically analyzed to establish the number of plants to be scouted per site and the most effective scouting techniques to use. Based on the data available and insects collected during the pilot sampling trial, a surveillance programme was designed. Five different types of monitoring traps were placed in each of the eight study sites. Collection of trap catches and scouting of fifteen individual plants per site was undertaken on a weekly basis over the 52-week study period. The most commonly occurring potential insect pests were African Bollworm Helicoverpa armigera (Hübner), False Codling Moth Thaumatotibia leucotreta (= Cryptophlebia leucotreta) (Meyrick), Mediterranean Fruit Fly Ceratitis capitata (Wiedemann) and several species of thrips. Population densities of these pests and their phenology on Capsicum were determined. Statistical analyses established the efficacy of the monitoring traps for each pest, tested for differences among and between study sites, calculated an estimate of the number of pods damaged and a measure of plant damage.The results show that the majority of damage caused to the Capsicum baccatum cropping system was due to Mediterranean Fruit Fly populations. It was established that, although African Bollworm and False Codling Moth were present during the study period, their numbers were negligible and only nominal damage was caused by these pests. Damage caused by thrips species was apparent but not quantifiable. Intervention strategies using an Integrated Pest Management approach, are discussed.
45
Potgieter, Linke. "A mathematical model for the control of Eldana saccharina Walker using the sterile insect technique." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85865.
Full textAbstract:
Thesis (PhD)--Stellenbosch University, 2013.ENGLISH ABSTRACT: Two mathematical models are formulated in this dissertation for the population growth of an Eldana saccharina Walker infestation of sugarcane under the influence of partially sterile released insects. The first model describes the population growth of and interaction between normal and sterile E. saccharina moths in a temporally variable, but spatially homogeneous environment. The model consists of a deterministic system of difference equations subject to strictly positive initial data. The primary objective of this model is to determine suitable parameters in terms of which the above population growth and interaction may be quantified and according to which E. saccharina infestation levels and the associated sugarcane damage may be measured. The second model describes this growth and interaction under the influence of partially sterile insects which are released in a temporally variable and spatially heterogeneous environment. The model consists of a discretized reaction-diffusion system with variable diffusion coefficients, subject to strictly positive initial data and zero-flux Neumann boundary conditions on a bounded spatial domain. The primary objectives in this case are to establish a model which may be used within an area-wide integrated pest management programme for E. saccharina in order to investigate the efficiency of different sterile moth release strategies in various scenarios without having to conduct formal field experiments, and to present guidelines by which release ratios, frequencies and distributions may be estimated that are expected to lead to suppression of the pest. In addition to the mathematical models formulated, two practical applications of the models are described. The first application is the development of a user-friendly simulation tool for simulating E. saccharina infestation under the influence of sterile insect releases over differently shaped spatial domains. This tool provides the reader with a deeper understanding as to what is involved in applying mathematical models, such as the two described in this dissertation, to real-life scenarios. In the second application, an optimal diversification of sugarcane habitats is considered as an option for minimising average E. saccharina infestation levels, and as a further consequence, improving the cost-efficiency of sterile insect releases. Although many special cases of the above model classes have been used to model the sterile insect technique in the past, few of these models describe the technique for Lepidopteran species with more than one life stage and where F1-sterility is relevant. In addition, none of these models consider the technique when fully sterile females and partially sterile males are being released. The models formulated in this dissertation are also the first to describe the technique applied specifically to E. saccharina, and to consider the economic viability of applying the technique to this species. Furthermore, very few examples exist of such models which go beyond a theoretical description and analysis towards practical, real-life applications as illustrated in this dissertation.
AFRIKAANSE OPSOMMING: Twee wiskundige modelle word in hierdie proefskrif vir die populasiegroei van ’n Eldana saccha- rina Walker infestasie van suikerriet onder die invloed van gedeeltelik steriele, vrygelate insekte daargestel. Die eerste model beskryf die populasiegroei van en -interaksie tussen normale en steriele E. saccharina motte in ’n dinamiese, maar ruimtelik-homogene omgewing. Die model is ’n stelsel deterministiese verskilvergelykings onderhewig aan streng positiewe aanvangswaardes. Die primˆere doelstelling met hierdie model is om geskikte parameters te bepaal in terme waarvan die bogenoemde groei en interaksie gekwantifiseer kan word, en waarvolgens E. saccharina infestasievlakke en die gepaardgaande suikerrietskade gemeet kan word. Die tweede model beskryf hierdie groei en interaksie onder die invloed van gedeeltelik steriele insekte wat in ’n dinamiese en ruimtelik-heterogene omgewing vrygelaat word. Die model is ’n gediskretiseerde stelsel reaksie-diffusievergelykings met veranderlike diffusieko¨effisi¨ente onderhewig aan streng positiewe aanvangswaardes en zero-vloei Neumann-randwaardes op ’n begrensde ruimtelike gebied. Die primˆere doelstellings in hierdie geval is om ’n model tot stand te bring wat in ’n area-wye, ge¨ıntegreerde pesbestrydingsprogram vir E. saccharina gebruik kan word om die doeltreffendheid van verskillende steriele motvrylatingstrategie¨e te bepaal sonder om daadwerklik veldeksperimente uit te voer, en om riglyne daar te stel waarvolgens vrylatingsverhoudings, -frekwensies en -verspreidings bepaal kan word wat na verwagting na ’n onderdrukking van die pes sal lei. Bykomend tot die wiskundige modelle in hierdie proefskrif, word twee praktiese toepassings van die modelle ook beskryf. In die eerste toepassing word ’n gebruikersvriendelike simulasie hulpmiddel ontwikkel om E. saccharina infestasie onder die invloed van steriele insekvrylatings in verskillende ruimtelike gebiede te simuleer. Hierdie toepassing fasiliteer ’n dieper begrip van wat ter sprake is in die toepassing van wiskundige modelle, soos die twee modelle in hierdie tesis, tot werklike scenario’s. In die tweede toepassing word ’n optimale diversifisering van suikerriet habitats as ’n opsie vir die vermindering van die gemiddelde E. saccharina infestasie vlakke beskou, en gevolglik word die verbetering van die koste-doeltreffendheid van steriele insekvrylatings afgeskat. Alhoewel verskeie spesiale gevalle van die bogenoemde twee klasse van modelle reeds in die verlede gebruik is om die doeltreffendheid van die steriele-insektegniek te modelleer, beskryf weinig van hierdie modelle die tegniek vir Lepidopteriese spesies met meer as een lewensfase en waar F1-steriliteit ter sprake is. Verder beskryf geen van hierdie modelle die tegniek waar algeheel steriele wyfies en gedeeltelik steriele mannetjies vrygelaat word nie. Die modelle in hierdie tesis is ook die eerste waar die tegniek spesifiek op E.saccharina toegepas word, en waar die ekonomiese lewensvatbaarheid van die tegniek vir hierdie spesie oorweeg word. Verder bestaan daar min voorbeelde van soortgelyke modelle wat verder gaan as ’n teoretiese beskrywing en wiskundige ontleding na praktiese, werklike toepassings, soos in hierdie proefskrif ge¨ıllustreer.
46
Zhao, Dingxin. "Mathematical models for the population dynamics and management of the carrot weevil, Listronotus oregonensis (LeConte) (Coleoptera:Curculionidae)." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74555.
Full textAbstract:
The time-varying survival rates of the carrot weevil, Listronotus oregonensis, were estimated by a new method. This method precluded the possibility of negative simulation survival rates. Analysis of carrot weevil population dynamics indicated that the egg mortality was density dependent with Anaphes sordidatus, an egg parasitoid, as a major density dependent factor. Larval mortality was less density dependent. Based on the mortality information, a simulation model for carrot weevil population dynamics was established. The simulation precision, evaluated by comparing simulated and observed egg and larval population dynamics, was satisfactory. Sensitivity analysis indicated that A. sordidatus had a large influence on carrot weevil population dynamics. The economic threshold for carrot weevil control in early carrots was 5 eggs/100 carrots at the peak population density. It ranged from 3.8 to 5.3 eggs/100 carrots in mid-season carrots depending on the selling price. A decision model showed that the best sowing date was after June 5 when risks were not considered. For risk aversion growers, sowing carrots between May 20 and May 31 was the best choice.
47
Jenkins, Paul E. "Control of the grape berry moth, Paralobesia viteana, using reduced-risk insecticides, cultural controls, and conservation of natural enemies." Diss., Connect to online resource - MSU authorized users, 2006.
Find full text
48
Mkize, Nolwazi. "Insect pests of cultivated and wild olives, and some of their natural enemies, in the Eastern Cape, South Africa." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1005403.
Full textAbstract:
This thesis has two focuses. The first problem facing the olive industry in the Eastern Cape is the growers’ perceptions of both what the industry will provide them and what a pest management program might entail. The second focus is the biology of olive pests in the Eastern Cape in terms of understanding their populations and their natural enemies on private farms, with future hopes of understanding how Integrated Pest Management strategies can be developed for this crop. Eastern Cape private farmers, small-scale farmers and workers from agricultural training institutions were interviewed regarding the history and cultivation of the local olive crop. Only one commercially viable olive grove was identified; other groves were small, experimental pilot ventures. The introduction of olives to small-scale farmers and agricultural training schools was generally a top-down initiative that led to a lack of sense of ownership and the trees being neglected. Other problems included poor human capital; poor financial capital; lack of adequate support; lack of knowledge transfer and stability; lack of communication and evaluation procedures of the project; miscommunication; and finally, olive pests. Apart from hesitancy to plant at a commercial scale, the main problem facing private farmers (Varnam Farm, Hewlands Farm and Springvale Farm) was pests. Therefore an investigation of pests from private farms was conducted ranging from collection of cultivated and wild olive fruit and flea beetle larvae for parasitism, trapping systems both for fruit flies and olive flea beetle adults. A survey of olive fruits yielded larval fruit flies of the families Tephritidae (Bactrocera oleae (Rossi), B. biguttula (Bezzi) and Ceratitis capitata (Wiedemann)) and Drosophilidae (Drosophila melanogaster (Meigen)) from wild olives (O. europaea cuspidata (Wall. ex G. Don) Cif.) but none from cultivated olives (O. e. europaea L.). Braconid wasps (Opiinae and Braconinae) were reared only from fruits containing B. oleae and B. biguttula. This suggests that B. oleae is not of economic significance in the Eastern Cape, perhaps because it is controlled to a significant level by natural enemies, but B. biguttula may be a potential economic pest. A survey of adult fruit flies using ChamP traps baited with ammonium bicarbonate and spiroketal capsules and Sensus trap baited with methyl eugenol and Questlure confirmed the relative importance of B. biguttula over B. oleae. ChamP traps were over 50 times better than Sensus traps for mass trapping of B. biguttula but both were ineffective for trapping B. oleae and C. capitata. Six indigenous flea beetles of the genus Argopistes Motschulsky (Chrysomelidae: Alticinae) were found, three described by Bryant in 1922 and 1944 and three new species. Their morphology was investigated by scanning electron microscopy and mutivariate morphometric analysis. The leaf-mining larvae are pests of wild and cultivated olives in South Africa and threaten the local olive industry. At Springvale Farm, A. oleae Bryant and A. sexvittatus Bryant preferred the upper parts of trees, near new leaves. Pseudophanomeris inopinatus (Blkb.) (Braconidae) was reared from 23 Argopistes larvae. The beetle larvae might not be controlled to a significant level by natural enemies because the rate of parasitism was low. The olive flea beetles showed no attraction to traps containing various volatile compounds as baits. The lace bug, Plerochila australis Distant (Tingidae), was sometimes a pest. It showed a preference for the underside of leaves on the lower parts of the trees. A moth, Palpita unionalis Hübner (Crambidae), was reared in very low numbers and without parasitoids. A twig-boring beetle larva, chalcidoid parasitoids and seed wasps of the families Eurytomidae, Ormyridae and Eupelmidae were also recorded.
49
Wallage, Helena Rachelle. "The effects of Plagiorchis elegans (Trematoda : Plagiorchiidae) infection on the carbohydrate metabolism of fourth instar Aedes aegypti (Diptera : Culicidae) larvae." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30763.
Full textAbstract:
Glucose was present in substantially greater concentrations in whole body extracts of fourth instar Aedes aegypti L. larvae than was trehalose; in contrast, trehalose was more abundant than glucose in haemolymph extracts. Preliminary studies suggested that infection of Ae. aegypti by the entomopathogenic digenean Plagiorchis elegans Rudolphi alters the carbohydrate metabolism of fourth instar larvae. Within 24 hours of cercarial penetration, total body extracts of infected fourth instar larvae exhibited decreased trehalase activity, increased trehalose-6-phosphatase activity, and an accumulation of trehalose in comparison to uninfected larvae. Concentrations of glucose, glycogen and lipids, and the activity of glycogen phosphorylase a were similar in extracts of infected and control larvae. The predominant fatty acids, in both control and infected larvae, were C 18:0, C 18:1 and C 18:3. There were no significant differences in the types and proportions of fatty acids found in control and infected larvae. Parasitic infection is discussed in terms of impaired trehalose metabolism.
50
Scudeler, Elton Luiz [UNESP]. "Efeito do óleo de nim (Azadirachta indica A. Juss) no intestino médio de Ceraeochrysa claveri (Navás, 1911) (Neuroptera: Chrysopidae): estudo citoquímico, imunocitoquímico e ultraestrutural." Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/99436.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:30:13Z (GMT). No. of bitstreams: 0
Previous issue date: 2012-02-24Bitstream added on 2014-06-13T18:59:57Z : No. of bitstreams: 1
scudeler_el_me_botib.pdf: 6021367 bytes, checksum: 931a3db0cfc7da410cba6a737f5365bf (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Ceraeochrysa claveri, popularmente conhecido como bicho lixeiro, é um inseto predador de ovos e larvas de insetos pragas encontrados em diferentes ecossistemas agrícolas. O bicho lixeiro se destaca por apresentar potencial para ser utilizado em programas de Controle Biológico, uma vez que é predador na fase de larva, apresenta curto tempo de desenvolvimento, fácil criação massal e alto potencial reprodutivo na fase adulta. Com o propósito de aprofundar o conhecimento na morfologia e ultraestrutura do intestino médio de C. claveri, o objetivo deste trabalho foi caracterizar histológica e ultraestruturalmente o intestino médio de C. claveri no terceiro ínstar de larva, pupa e adulto. Objetivamos, ainda, avaliar o efeito da ingestão do óleo de nim (Azadirachta indica A. Juss) (Meliaceae) sobre as células epiteliais do intestino médio de larva de terceiro ínstar, pupa e adulto de C. claveri. Ovos de Diatraea saccharalis foram tratados com óleo de nim em três diferentes concentrações (0,5; 1 e 2%) e oferecidos como alimento a larvas de C. claveri durante todo período larval. Após coleta e fixação do intestino médio de larva, pupa e adulto (grupos controle e tratados com óleo de nim), as regiões do mesêntero (anterior, média e posterior) foram processadas para análise histológica (citoquímica e imunocitoquímica) e para análise ultraestrutural. Nossos resultados mostraram que o intestino médio de C. claveri, para as três fases do ciclo de vida, é do tipo pseudoestratificado, composto por células colunares, regenerativas e endócrinas; diferenças morfológicas e ultraestruturais no epitélio permitem caracterizar duas regiões, anterior e posterior, atuando respectivamente na secreção e absorção; região média apresenta características...
Ceraeochrysa claveri, popularly known as trash-carriers is a predator insect of eggs and larvae of insect pests found in different agroecosystems. The trash-carriers stands out because it has the potential to be used in biological control programs, once it is a predator in the larval stage; it has short developmental times, easy mass-rearing and high reproductive potential in adult stage. In order to deepen the knowledge on the morphology and ultrastructure of the midgut of C. claveri, the aim of this study was to characterize histological and ultrastructurally the midgut of C. claveri in the third instar larva, pupa and adult. We also evaluate the effect of ingestion of neem oil (Azadirachta indica A. Juss) (Meliaceae) on the midgut epithelial cells of third instar larva, pupa and adult of C. claveri. Diatraea saccharalis eggs were treated with neem oil at three different concentrations (0.5, 1 and 2%) and provided as food to larvae of C. claveri throughout the larval period. After collected and fixed the midgut of larva, pupa and adult (control and treated groups with neem oil), the midgut regions (anterior, middle and posterior) were processed for histological (cytochemistry and immunocytochemistry) and for ultrastructural analysis. Our results showed that the midgut of C. claveri for the three phases of the life cycle is of pseudostratified type, consisting of columnar cells, regenerative cells, and endocrine cells, morphological and ultrastructural differences in the epithelium allowed to characterize two regions, the anterior and posterior, they working mainly in the secretion and absorption respectively; the middle region has intermediate characteristics, and it is considered a transitional area. The ingestion of neem oil in the larval stage of C. claveri showed to be toxic to this predator, causing ultrastructural alterations... (Complete abstract click electronic access below)