Dissertations / Theses on the topic 'Insecticides Evaluation'
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1
Malima, Robert Chikoja Munyu. "Evaluation of long lasting insecticidal materials and treatment kits and control of pyrethroid insecticide resistant mosquitoes using alternative insecticides on nets." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.536834.
2
Umeda, Kai, and Chris Fredman. "Evaluation of Insecticides for Aphid Control in Cabbage." College of Agriculture, University of Arizona (Tucson, AZ), 1996. http://hdl.handle.net/10150/214743.
Abstract:
Experimental insecticides CGA-215944 (Ciba), pyriproxyfen (S-71639, Valent), and RH-7988 (Rohm and Haas) demonstrated very good efficacy in reducing the aphid population in cabbage. Fipronil (Rhone-Poulenc) was not as effective in controlling the aphids relative to the other treatments. Acephate (Orthene®), chlorpyrifos (Lorsban™), and naled (Dibrom®) were highly effective relative to the untreated check.
3
Umeda, Kai, and Gabriel Towers. "Evaluation of Insecticides for Efficacy on Turfgrass Pests." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2008. http://hdl.handle.net/10150/216634.
Abstract:
No masked chafer larvae were observed for treatments of imidacloprid, imidacloprid plus bifenthrin, clothianidin, and the two higher rates of DPX-E2Y45. The inconsistent and low populations of masked chafer larvae and billbugs in the turfgrass did not provide for conclusive results. Clothianidin and the two higher rates of DPX-E2Y45 had no billbug larvae. An early rating date showed that more billbug adults were in turf treated with imidacloprid and DPX-E2Y45. Later rating dates showed a decline in adults for all treatments.
4
Umeda, Kai. "Evaluation of Foliar Insecticides for Whiteflies in Cantaloupes." College of Agriculture, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/219967.
Abstract:
A single application of buprofezin (Applaud7) at 0.38 lb AI/A had the fewest number of adult whiteflies (WF) on rating dates at 13, 21, and 27 days after treatment (DAT). The number of immature WF at 21 DAT of a single Applaud application ranged from 0.8 to 5.2 nymphs/leaf, significantly less than the untreated. Applaud treatments were effective in minimizing the immatures for 21 DAT of a single application and then numbers began to increase before 27 DAT. Applaud plus two subsequent weekly applications of bifenthrin (Capture7) plus endosulfan (Thiodan7, Phaser7) was almost similar to single applications of Applaud alone and adult numbers were also low. Weekly applications of the pyrethroids plus endosulfan reduced the adult WF relative to the untreated at 1 week after treatment (WAT). At 2 WAT of the third application, fenpropathrin (Danitol7) and Capture continued to show reduced numbers of adults and esfenvalerate (Asana7) was similar to the untreated. Danitol treatments had numerically fewer adults than Capture which was lower than Asana. The lowest adult and immature WF populations were observed season-long in the CGA-293343 (Novartis) treated cantaloupes. Both rates, 0.067 and 0.09 lb AI/A performed similarly and numerically slightly fewer nymphs were observed for the higher rate. CGA-293343 plus CGA-215944 (pymetrozine, Fulfill7) performed similar to the two rates of CGA-293343 alone.
5
Palumbo, John C. "Evaluation of Neonicotinoid Insecticides for Whitefly Management in Melons." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2002. http://hdl.handle.net/10150/214926.
Abstract:
Several studies were conducted in the spring and fall 2001 to evaluate a number of neonicotinoid compounds (Admire, Calypso, Actara, Platinum and dinotefuron) for whitefly control in spring and fall melons. The results of these studies demonstrate that several insecticide products are being developed that offer melon growers management alternatives for controlling whiteflies. The new foliar neonicotinoid Calypso (thiacloprid), shows excellent promise as a foliar, post-planting spray with 14-21 day residual. Further, no consistent negative interaction was detected between Platinum and fertilizer, 10-34-0 and UN 32, applied together as at-planting or side dress soil treatments. These treatments provided good whitefly control, but further research is needed to replicate these effects as Platinum has been labeled at lower rates than the manufacturer initially anticipated. At planting applications of Platinum at 8 oz (current labeled rate) did however provide acceptable residual control of whiteflies on fall melons under heavy population pressure.
6
Umeda, K., D. MacNeil, D. Roberts, and N. Lund. "Evaluation of Foliar Insecticides for Whitefly Control in Cantaloupes." College of Agriculture, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/219996.
Abstract:
The pyrethroid insecticides esfenvalerate (Asana®), bifenthrin (Capture®), or fenpropathrin (Danitol®) combined with endosulfan effectively reduced whitefly (WF, Bemisia argentifolii) counts at 1 week after treatment (WAT) following each of five applications. Asana, Capture, or Danitol combined with endosulfan effectively reduced WF counts at 1 WAT following each of five applications. Danitol treated melons exhibited fewer adult WF compared to Asana or Capture at most of the rating dates at 6 days after treatment (DAT) of each of the applications and also at 11 DAT of the last application. A single application of buprofezin (Applaud®) treatments or pymetrozine (Fulfill®) effectively reduced WF nymphs for 18 to 24 DAT and adults were reduced for 18 DAT. Fulfill exhibited a rate response where the higher rate reduced WF counts more than the lower rate.
7
Umeda, Kai, and Chris Fredman. "Evaluation of Insecticides for Lepidopterous Insect Pest Control in Cabbage." College of Agriculture, University of Arizona (Tucson, AZ), 1996. http://hdl.handle.net/10150/214747.
Abstract:
Experimental insecticides MK-244 (Merck), Alert (AC 303630, Cyanamid), and Confirm (RH-5992, Rohm and Haas) demonstrated very good efficacy in reducing the lepidopterous pests including plutell4 xylostella (diamondback moth, DBM) and Tricoplusia at (cabbage looper, CL) in cabbage. The total number of small, medium, and large DBM larvae for all treatments was lower than the untreated at most rating dates. The experimental insecticides compared favorably with commercially available products Lannate®, Larvin®, and Kryocide®.
8
Arias, Gladys Antonieta Rojas de. "Evaluation of Chagas control techniques in Paraguay." Thesis, Bangor University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318078.
9
Hundley, Christopher Alan. "Evaluation of organophosphate insecticides on performance of transgenic and conventional cotton." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/2189.
Abstract:
Genetically modified cotton (Gossypium hirsutum L.) acreage has increased dramatically over the last six years. Reports of variable results in fiber quality and yield have arisen in these cultivars. Some changes in production practices have occurred coincident with the introduction of transgenic technology, such as reduced use of broad-spectrum insecticides, including organophosphates (OP) that could potentially influence the growth and yield of cotton. One factor that might affect these parameters is the difference in the amount of foliarly-applied phosphorus (P) between an OP and non-phosphate (NP) insecticide regime. Therefore, a study was conducted to investigate selected growth characteristics, yield, and fiber quality of genetically modified and conventional cotton as influenced by OP and foliar phosphorus (FP) applications. A four replication strip-plot experimental design was utilized with cultivar serving as the whole plot and insecticide regime as the sub-plot. Three cultivars of the same recurrent parent (ST4892BR, ST4793R, and ST474) were planted in 2001 and 2002 under irrigated conditions in Burleson County, TX on a Weswood silty clay loam (fine-silty, mixed, thermic Fluventic Ustochrept). The insecticide regime consisted of NP, NP+FP, and OP treatments. The FP was applied at P2O5 weight equivalent to the P component in the concurrent OP application. ST4892BR had greater lint yield than ST4793R and ST474. The yield increase can be explained through plant mapping analysis which showed ST4892BR producing larger bolls and greater boll numbers. In addition, evaluation of fruiting distribution showed ST4892BR contained more lint on sympodial branches 6 through 10. The insecticide regime effect on lint yield resulted in higher yield (P=0.08) for the NP+FP regime. Examination of yield components revealed NP+FP increased second position bolls, predominantly at sympodial branches 6 through 10. Leaf tissue analysis revealed increased levels of P for the OP and NP+FP over that of the NP insecticide regime, which indicates a potential for plants to acquire P from OP insecticides. Furthermore, the considerable yield response to small amounts of FP is not clearly understood. While conclusive evidence exists regarding cultivar yield differences, this study does not provide sufficient evidence to conclude that OP insecticides influence growth, yield, or fiber quality characteristics of these cotton cultivars.
10
Rethwisch, Michael D. "Evaluation of Insecticides and Oils for Jojoba Scirtothrips ewarti bailey Control." College of Agriculture, University of Arizona (Tucson, AZ), 1990. http://hdl.handle.net/10150/215721.
11
Rethwisch, Michael D., Charles W. McDaniel, and James Thiessen. "Evaluation of Insecticides for Control of the Apache Cicada on Asparagus." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/214524.
Abstract:
Five insecticides were evaluated for Apache cicada control in asparagus. Best control was achieved by two unregistered pyrethroid insecticides. The currently registered pyrethroid insecticide in this study (Pounce) was not as effective as Capture or Baythroid. Methomyl Pinnate) applied after the experiment was also very effective in controlling adult Apache cicadas. Di-Syston provided very little control.
12
Kerns, David L., and Tony Tellez. "Evaluation of New Insecticides for Aphid Control in Green Leaf Lettuce." College of Agriculture, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/219976.
Abstract:
New soil injected and foliar insecticides were evaluated for their efficacy towards potato aphids in green leaf lettuce. The soil injected insecticides, Platinum and V10066, both appear to be viable alternatives to Admire, providing effective aphid control through harvest or ca. 90 days post-planting. Two foliar applications of Acetamiprid or Aphistar timed ca. 14 days apart beginning at the onset of aphid colonization provided superior aphid control over Provado or Fullfill, and control similar to that of the soil injected insecticides.
13
Palumbo, John C., Marvin D. Butler, and Clayton H. Jr Mullis. "Evaluation of Biological Insecticides for Control of Beet Armyworm in Lettuce." College of Agriculture, University of Arizona (Tucson, AZ), 1991. http://hdl.handle.net/10150/221457.
Abstract:
A field study was conducted at Yuma in 1990 to examine the efficacy of several biological insecticide formulations on beet armyworm in seedling lettuce. After a single application at thinning, none of the insecticides adequately reduced larval populations below damaging levels. Reductions in plant stand by larvalfeeding were significantly lower in plots treated with Lannate, Javelin, Biobit and Dipel. Lettuce seedling densities were reduced greaterthan 80% in untreated plots.
14
Jiang, Ying. "Evaluation of Novel Carbamate Insecticides for Neurotoxicity to Non-Target Species." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/41236.
Abstract:
Malaria (vector: Anopheles gambiae) is a major infectious disease that kills about 1 million people each year. For the improvement of its treatment and vector control during the past decades, several issues such as high medicine cost, insecticide resistance, and lack of an effective vaccine have prevented adequate control of malaria. Additionally, the low selectivity of malaria vector insecticides also presents a public health problem. The purpose of developing novel carbamate insecticides in our laboratory is to offer effective and selective insecticide options to achieve the ultimate goal of malaria control.
First, 50% inhibition concentration (IC50) data was collected from three mammalian AChEs with eight commercial carbamate insecticides by using the Ellman assay. The IC50 values varied from 57 nM to 7358 nM. The AChE sensitivity pattern and level were shown to be similar between the recombinant mouse and ICR male mouse brain cortex homogenate (slope = 0.99, R2 = 0.96). Then eight novel carbamate insecticides that are possible malaria vector control agents were selected for further neurotoxicity testing in non-target organisms. For commercial carbamate insecticides, the IC50 varied from 9.1 nM to 2,094 nM. For the novel carbamate insecticides, it varied from 58 nM to 388,800 nM. Based on IC50 data from previous work on A. gambiae, the selectivity index (IC50 of non-target species / IC50 A. gambiae) ranged from 0.17 to 5.64 and from 0.47 to 19,587 for commercial and novel carbamate insecticides, respectively.
Subsequently, the AChE protein sequence alignment comparison and cladogram were used to compare the genetic and evolutionary relationship among five different organisms. The alignment score ranged from 88 for mouse vs. human to 54 for hen vs. T. californica. The evolutionary relationships among species was obtained from the cladogram. Recombinant mouse vs. recombinant human was shown to have the most similar inhibitor potency profiles (alignment score = 88, closest taxa position on cladogram, similar AChE sensitivity pattern [R2 = 0.81] and level [P > 0.05] to the novel carbamates).
Neurotoxic esterase (NTE) assay showed that the novel carbamates did not significantly inhibit NTE, inhibition of which underlies a significant hazard for anticholinesterases, especially organophosphates, in several nontarget vertebrate organisms. The NTE activity in the presence of novel carbamate insecticides ranged from 93% to 116% of the control, while in the commercial group, bendiocarb significantly inhibited NTE, leaving only 76.5% of the initial reactivity at 1 mM inhibitor concentration.
Further in vivo bioassay using Daphnia magna was conducted to compare the aquatic toxicity of commercial and novel carbamates. The data showed that except for PRC331 (3-tert-butylphenylmethylcarbamate), all novel carbamates were of similar potency as bendiocarb (LC50 = 611 nM) for aquatic toxicity, and their LC50 values ranged from 172 nM (PRC331) to 1109 nM.
In conclusion, the novel carbamate insecticides would appear to be an improvement over commercial carbamate insecticides because of greater selectivity, negligible NTE inhibition capacity, but in some cases with potent in vivo toxicity to Daphnia magna. However, since the envisioned usage of these compounds is in bednets or as indoor residual sprays (IRS), any environmental exposures to nontarget aquatic organisms are expected to be minimal.Master of Science
15
Rethwisch, Michael D., Jessica Grudovich, Steven Bennett, and Mark Reay. "Evaluation of Various Insecticides for Late Winter/Early Spring Insect Control, 2004." College of Agriculture, University of Arizona (Tucson, AZ), 2005. http://hdl.handle.net/10150/203838.
Abstract:
Nine insecticides were applied on March 10, 2004, to alfalfa that had been water stressed prior to irrigation on March 6. These actions were thought to have resulted in treatments means with less distinct differences than usually noted for these treatments at 7-14 days post treatment. All pyrethroid treatments as well as Lorsban® and Steward® treatments resulted in significant reductions of alfalfa weevil larvae at four days post treatment. The Trilogy® treatment did not result in acceptable control of this pest. Significant increases in adult alfalfa weevils were noted at 10-14 days post treatment in pyrethroid treated alfalfa, perhaps due to increased production of certain plant volatiles in response to this class of insecticides. Low numbers of blue alfalfa aphids were noted in this study partially due to insecticide control as well as numerous beneficial insects. Fewest damsel bugs were noted from alfalfa treated with MustangMAXTM and Warrior® insecticides.
16
Harwood, Amanda D. "Temperature as a toxicity identification evaluation tool for pyrethroid insecticides : toxicokinetic confirmation /." Available to subscribers only, 2008. http://proquest.umi.com/pqdweb?did=1594480611&sid=9&Fmt=2&clientId=1509&RQT=309&VName=PQD.
17
Kerns, David L., and Tony Tellez. "Evaluation of Knack for Aphid Control in Green Leaf Lettuce." College of Agriculture, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/219963.
Abstract:
Knack was evaluated for its potential for regulating aphid populations in green leaf lettuce. However, Knack did not appear to be a viable control option, and probably did not work due to an inability to deliver the material where the aphids were on the underside of the lower leaves. A soil injection treatment of Admire at planting, and a foliar standard of Warrior + Endosulfan applied at the initiation of aphid colonization and again 14 later, were highly effective treatments.
18
Hauxwell, Irene Caroline. "Evaluation of potential baculovirus insecticides : studies of the infection process and host susceptibility." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312316.
19
Garcia-Alonso, Monica. "Evaluation of the potential of murine erythroleukemia (MEL) cells as an expression system for nicotinic acetylcholine receptors." Thesis, University of Reading, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389643.
20
Rethwisch, Michael D., Michael Meadows, and Larry Hood. "Evaluation of Oils and Insecticides for Leafminer Control in La Paz County Snap Beans." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/214505.
21
Palumbo, John, Clayton Jr Mullis, Francisco Reyes, and Andreas Amaya. "Evaluation of Conventional and Experimental Insecticides for Control of Western Flower Thrips in Head Lettuce." College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/221645.
Abstract:
Studies were conducted in small plot field trials to evaluate the efficacy of several experimental and conventional insecticide chemistries against western flower thrips in head lettuce. Results from two trials using new experimental compounds showed that several insecticides have potential for management of thrips populations. All of the products appear to be good candidates for thrips control and had efficacy against adults and nymphs. Success and Fipronil consistently provided comparable control to the standard Lannate/Ammo. In the trial evaluating conventional compounds, Orthene/Mustang and Lannate/Ammo combinations provided the best control of both adult and nymphs. Plant size and temperature may be important factors contributing to the efficacy of these products.
22
Asidi, Alex Ndongidila. "Evaluation of nets treated with alternative insecticides against pyrethroid resistant mosquitoes and pyrethroid tolerant bedbugs." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411599.
23
Rethwisch, Michael D., Tony Tellez, Alphonso Tellez, David Tellez, Mary Shaw, Alex Galarza, and Luis Lastra. "Evaluation of Oils, Insecticides and Insect Growth Regulators for Control of Sweetpotato Whitefly on Muskmelon and Watermelon." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/214506.
Abstract:
Five insecticides, four oils, one soap, and two insect growth regulators were evaluated for control of sweetpotato whitefly on muskmelons and watermelons in 1990. Best control (> 80%) was noted from the insect growth regulators at 11 days post treatment, but declined thereafter. Oils as a class provided some control but not all oils provided similar results. Insecticides tested did not provide adequate control and resulted in increased whitefly egg and nymph numbers at 11 days post treatment.
24
Li, Xiubin. "Synthesis of new dicinnamoyl quinic acid derivatives and analogs and the evaluation of their potential as biopesticides." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI032/document.
Abstract:
L'utilisation de pesticides conventionnels, en particulier les pesticides chimiques de synthèse, a considérablement réduit les pertes de récoltes et a connu un succès commercial. Cependant, l'utilisation excessive de pesticides chimiques qui manquent de toxicité spécifique a provoqué une série de problèmes environnementaux et de santé publique. L'intérêt de la recherche vers de nouveaux biopesticides naturels avec de nouveaux modes d'actions vise à un meilleur équilibre entre l'efficacité des pesticides et la réduction des méfaits possibles pour l'environnement et les humains. Les plantes sont une source importante de biopesticides. Les acides chlorogéniques (CQA), isolés à partir de diverses plantes et présentent in vivo et in vitro un large spectre d'activités biologiques, ont attiré l'attention avec un potentiel comme biopesticides basé sur la toxicité brevetée de l'acide 3,5-di-O-caféoylquinique contre les larves de Myzus persicae. L'étude des propriété insecticides notamment la mode d'action et l'étude de certaines relations structure-activité pourrait bénéficier de la synthèse de différents dérivés et analogues de CQA. Des analogues des acides 4-désoxy-3,5-dicinnamoy quiniques et 3,4- et 4,5-dicinnamoylquiniques naturels ont été synthétisés. Sept analogues dans la série 4-désoxy ont été soumis à des essais insecticides et deux composés présentent une activité insecticide plus élevée que l'acide 3,5-dicaféoylquinique naturel. Comme perspectives à ce travail, confirmer l'activité des composés synthétisés sur d'autres espèces de pucerons d'importance agronomique pourrait être réalisé. De plus, d’autres collaborations avec des biologistes pourraient être établies afin d’évaluer d'autres activités des composés synthétisés ou les utiliser comme outils pour étudier des mécanismes de biosynthéseThe use of conventional pesticides, especially the synthetic chemical pesticides, has greatly reduced the crop losses and gained a commercial success. However, the excessive use of pesticides lacking toxic specificity has caused a series of environmental and public health problems. The research interest toward new naturally-occurring biopesticides with novel modes of actions aims at a better balance between the efficiency of pesticide and reducing possible harms to environment and humans. Botanicals are an important source of biopesticides. Cinnamoyl quinic acids (CQA), isolated from various plants and shown to exhibit in vivo and in vitro a wide spectrum of biological activities, have attracted the attention with potential as biopesticides based on the patented toxicity of 3,5-di-O-caffeoylquinic acid against the larvae of Myzus persicae. The investigation of the insecticidal activity of CQA including their mode of action and the study of some structure-activity relationships could benefit from the synthesis of different CQA derivatives and analogs. A series of natural CQA derivatives natural 3,4- and 4,5-dicinnmamoylquinic acid derivatives but also analogs like 4-deoxy-3,5-dicinnamoylquinic acids were so synthesized. Seven targeted 4-deoxy CQA analogs were subjected to insecticidal assays, and two compounds were found to exhibit higher insecticidal activities than natural 3,5-dicaffeoylquinic acid. As perspectives to this work, confirming the activity of the synthesized compounds on other aphid species of agronomic importance could be performed. Furthermore, other collaborations could be established with biologists dedicated to measure other bioactivities of the synthesized compounds or use them as tools to investigate various biological pathways
25
Oxborough, R. M. "Laboratory and experimental hut evaluation of mosquito net and indoor residual spray (IRS) insecticides for improved malaria control." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2014. http://researchonline.lshtm.ac.uk/2092344/.
Abstract:
Since the start of Roll Back Malaria (RBM) in 1998 funding for malaria control has increased dramatically, resulting in the current peak of $2.5billion spent on global malaria control annually. Vector control has been a major source of expenditure, with the focus in sub-Saharan Africa being free Long-Lasting Insecticidal Net (LLIN) distribution and Indoor Residual Spraying (IRS). Use of pyrethroid insecticides in agriculture and rapid scaling up of pyrethroid LLINs and IRS for malaria vector control has led to the development and spread of pyrethroid resistance in Anopheles gambiae malaria vectors. In community use, the level of insecticide resistance at which malaria control is compromised remains uncertain, but experimental hut trials in Benin, an area of high frequency pyrethroid resistance, showed that holed pyrethroid Insecticide Treated Nets (ITNs) failed to protect sleepers from being bitten and no longer had a mass killing effect on malaria vectors. If LLINs and IRS are to remain effective it is essential that new public health insecticides are developed to address the growing problem of resistance. All insecticides that are currently recommended by the World Health Organization Pesticide Evaluation Scheme (WHOPES) for LLIN or IRS belong to just four classes of chemistry that act on nerve and muscle targets; namely pyrethroid, organophosphate (OP), carbamate, and organochlorine (DDT). The Global Plan for Insecticide Resistance Management (GPIRM) states that in areas of pyrethroid resistance or high LLIN coverage, alternative insecticide classes should be used for IRS in a rotation. Rotation of insecticides is very difficult to implement due to a lack of new public health insecticides. The Stockholm Convention on Persistent Organic Pollutants (POPs) came into effect in 2004, yet the use of DDT (classified as a POP) for malaria control has been allowed to continue under exemption since then due to a perceived absence of equally effective and efficient alternatives. Alternative classes of insecticide for IRS such as pirimiphos-methyl (OP) and bendiocarb (carbamate) have a relatively short residual duration of action (2-6 months according to WHOPES). In areas of year-round transmission, multiple spray cycles are required resulting in significantly higher costs for malaria control programs and user fatigue. For continued cost-effectiveness of IRS programs it is important to develop new longer-lasting formulations of currently available insecticides, while also developing insecticides with new modes of action. Pyrethroids are the only insecticides that are currently recommended by WHOPES for LLIN. Therefore, it is essential to develop and evaluate new insecticides for LLIN before effectiveness of pyrethroid LLIN is compromised. 6 This thesis consisted of a sequence of tests to evaluate the efficacy of several new formulations of WHOPES recommended insecticides and novel insecticides both in the laboratory and against wild mosquitoes entering experimental huts. Specifically these studies have shown that: Addition of eave baffles in experimental huts succeeded in reducing the potential for mosquito escape and is preferable to the assumption of doubling veranda catch to allow for unrecorded escapes (research paper 2). A Capsule Suspension (CS) formulation of pirmiphos-methyl used for IRS showed a significant improvement in terms of longevity on mud, concrete and plywood when compared with the previously recommended Emulsifiable Concentrate (EC) formulation in laboratory and experimental hut bioassays (research paper 3). A new formulation of deltamethrin with polymeric binder (SC-PE) for IRS showed only a slight improvement over the existing Water Dispersible Granules (WG) formulation in bioassays, but both formulations equalled DDT in experimental huts and should provide annual mosquito control. Deltamethrin SC-PE or WG should only be considered for use by malaria control programs where there is low pyrethroid LLIN coverage (research paper 4). In experimental hut trials, chlorfenapyr (pyrrole) IRS was equivalent to alphacypermethrin against pyrethroid susceptible An. arabiensis but superior against pyrethroid-resistant Cx. quinquefasciatus. The unique non-neurological mode of action shows no cross-resistance to existing resistance mechanisms and should be successful for control of pyrethroid resistant mosquitoes (research paper 5). In experimental hut trials, chlorfenapyr ITNs produced relatively high mortality rates of pyrethroid susceptible An. arabiensis but due to low irritability there was only a small reduction in blood-feeding (research paper 8). Mortality rates were similar to those produced by deltamethrin ITN. Unlike neurotoxic insecticides, such as pyrethroids and carbamates, chlorfenapyr owes its toxicity to the disruption of molecular pathways which enable cellular respiration to occur. Conventional 3 minute contact bioassay based on WHOPES guidelines is suitable for pyrethroids but does not predict field performance of 7 chlorfenapyr, which is metabolic in nature and sensitive to temperature and the phase of the insect’s circadian activity rhythm (research paper 9). Combining chlorfenapyr with a more excito-repellent pyrethroid on mosquito nets produced higher levels of blood-feeding inhibition than chlorfenapyr alone, in tunnel tests with both pyrethroid susceptible and resistant strains of Cx. quinquefasciatus (research paper 10). Restricting insecticide to particular surfaces of the nets (top only or sides only) indicated that An. arabiensis contacts both the top and sides of a mosquito net during host-seeking behaviour. These results support the rationale behind the ‘2-in-1’ mosquito net, in which the top of the net is treated with a non-pyrethroid insecticide and the sides with pyrethroid (research paper 11).
26
Kerns, David L., and Tony Tellez. "Commercial Evaluation of M-96-015 for Control of Citrus Mealybug, Woolly Whitefly and Citrus Thrips in Lemons." College of Agriculture, University of Arizona (Tucson, AZ), 1998. http://hdl.handle.net/10150/220526.
Abstract:
M-96-015 did not appear to effectively control woolly whitefly but does appear to kill citrus mealybug. However, as with other insecticides coverage is a problem. The real benefit of M-96-015 towards citrus mealybug would occur if it prevented their spread. However, we were not able to measure this in this study. As with previous trials, M-96-015 is an effective citrus thrips material.
27
Sehgal, Blossom. "Stored-grain insect management with insecticides: evaluation of empty- bin and grain treatments against insects collected from Kansas farms." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/15528.
Abstract:
Master of ScienceDepartment of Grain Science and Industry
Bhadriraju Subramanyam
The insecticides, β-cyfluthrin and chlorpyrifos-methyl plus deltamethrin, are approved in the United States for treating empty bin surfaces. Chlorpyrifos-methyl plus deltamethrin and spinosad insecticides are approved for direct treatment of wheat. The efficacy of commercial formulations of β-cyfluthrin and chlorpyrifos-methyl plus deltamethrin at labeled rates was evaluated against adults of 16 field strains of the red flour beetle, Tribolium castaneum (Herbst); seven strains of sawtoothed grain beetle, Oryzaephilus surinamensis (L.); and two strains of the lesser grain borer, Rhyzopertha dominica (F.). Concrete arenas in plastic Petri dishes (9 cm diameter) were used to simulate the concrete floor of empty bins. The time for ~100% knockdown and mortality of adults of laboratory strains of the three species was first established by exposing them to insecticide-treated concrete surfaces for 1 to 24 h. Adults of field strains of each species were exposed to specific established insecticide-time combinations. Mortality of all species was lower than knockdown, suggesting recovery after seven days when placed on food. Chlorpyrifos-methyl plus deltamethrin did not control all R. dominica and most O. ]surinamensis field strains. β-cyfluthrin was extremely effective against R. dominica but ineffective against T. castaneum and O. surinamensis field strains, even at four times the high labeled rate. Field strains of R. dominica were highly susceptible to spinosad and chlorpyrifos-methyl plus deltamethrin at labeled rates on hard red winter wheat. Strains of T. castaneum and O. surinamensis were susceptible only to the latter insecticide. Dose-response tests with spinosad on the two least susceptible field strains of each species showed the lethal dose for 99% mortality (LD[subscript]99) for T. castaneum and R. dominica field strains were similar to that of the corresponding laboratory strains. Corresponding values for the two O. surinamensis field strains were significantly greater (~6 times) than the laboratory strain. The effective dose for progeny reduction (ED[subscript]99) of only one R. dominica field strain was significantly greater (~2 times) than that of the laboratory strain. The baseline susceptibility data of field strains of three insect species to spinosad will be useful for monitoring resistance development once this product is commercially released as a grain protectant.
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Budeli, Mutshinya Ananias. "Genetics evaluation of tick resistance in South African Bonsmara cattle." Thesis, University of Limpopo (Turfloop Campus), 2010. http://hdl.handle.net/10386/883.
Abstract:
Thesis (M.Sc. (Agric.)) --University of Limpopo, 2010The objectives of the study were to estimate genetic parameters for tick resistance and to evaluate the effect of the level of tick infestation on the estimates of genetic parameters in South African Bonsmara cattle. Field data of repeated tick count records (n = 11 280) on 1 176 animals were collected between 1993 and 2005 by ten breeders participating in the National Beef Recording and Improvement Scheme. The distribution of tick count records were normalized using a Box-Cox transformation. Data were divided into 7 sub-data sets based on the mean tick count per contemporary group, to facilitate the investigation of the effect of level of tick infestation on the derived genetic parameters. A repeatability animal model including the fixed effects of contemporary group and age of animal at tick counting and random effects of the direct additive genetic, permanent environmental and residual effects was used to estimate genetic parameters using REML procedures. The additive genetic variances for tick count ranged from 0.01 to 0.08. Variances for the permanent environment ranged from 0.00 to 0.03. Phenotypic variance decreased with increasing mean tick count level while additive genetic variance increased with increasing mean tick count level. The heritability also increased with mean tick count level until a mean tick count level of ≥30. The highest heritability estimate obtained in the current study was 0.17 for data with mean tick count level ≥25. These results suggest that sufficient genetic variation for tick count exists in the Bonsmara cattle. Therefore genetic selection for tick resistance is feasible even though genetic progress may be slow.
the Limpopo Department of Agriculture (LDA) and the Department of Science and Technology (DST)
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Boulogne, Isabelle. "Evaluation du potentiel insecticide et antifongique sur Acromyrmex octospinosus (Reich) d'une sélection de plantes à usages etnopharmacologiques TRAMIL." Thesis, Antilles-Guyane, 2011. http://www.theses.fr/2011AGUY0469/document.
Abstract:
Les attines sont des fourmis champignonnistes dans la zone allant des Etats-Unis à l'Argentine en passant par la Caraïbe. Les dégâts causés par ces ravageurs sont considérables et estimés à plusieurs millions de dollars par an. Elles sont de ce fait considérées comme l'un des premiers fléaux de l'agriculture de la zone (Cameron & Riggs, 1985 ; Fowler et al., 1986). En Guadeloupe, la "fourmi manioc" (Acromyrmexoctospinosus Reich) cause de nombreux dommages, aussi bien pour l'agriculture que dans les milieux naturels. Les dégâts occasionnés par ces fourmis ont nécessité l'utilisation de pesticides de synthèse. pour tenter de les combattre. La dangerosité de ces substances pour les milieux naturels et anthropisés ainsi que pour la santé publique est un contexte favorable à l'exploration de nouvelles pistes telles que l'utilisation de plantes à usages phytosanitaires. L'objet principal de cette thèse consiste à savoir si on peut déceler à partir de l'ethnopharmacologieTRAMIL des usages permettant de combattre cette fourmi et son symbiote fongique, Leucocoprinuss 'gongylophorus (Heim) MoeIler. Les protocoles retenus et présentés dans ce travail permettent d'observer les effets des usages de plantes choisis sur la survie et le comportement des insects et sur la croissance du symbiote. Ils ont été sélectionnés pour leur potentialité à mettre en évidence les différents types d'effets des extraits végétaux (insecticide par contact, insectifuge, toxique par ingestion, fongistatique ou fongicide). Six usages traditionnels issus de cinq plantes sont testés sur la fourmi: Mammea americana L., Nerium oleander L., Nicotiana tabacum L., Rollinia mucosa (Jacq.) Baill. et Trichilia pallida Sw. Cinq autres usages traditionnels sont testés sur le champignon : Allium cepa L., Allium sativum L., Lycopersicom esculentum Mill., Manihot esculenta Crantz et Senna alata (L.) Roxb. Les resultants obtenus permettent de dégager quelques pistes de lutte intéressantes contre ce ravageurLeaf-cutting ants are fungus-growing ants.Their geographie distribution ranges from southern United States to northern Argentina, incIuding the West Indies, Economic losses due to these ants were estimated at several million dollars per year. The latter statement makes they are considered as one of the most important pest species of the agricultural productions (Cameron & Riggs, 1985 ; Fowler et al., 1986). In (Guadeloupe, the most important invasive pest species which caused important losses in forests, gardens and field crops is 'cassava ant' (Acromyrmex octospinosus Reich). These huge losses required to use, synthetic chemical pesticides to control these leaf-cutting ants, the consequence of which is, irreversible' injuries on environment and on human health. As a matter of fact, this situation has prompted an increasing interest in alternative methods for pest control like plants with pesticide used. The main objective of this thesis is to know if traditional ethnopharmacological TRAMIL uses could help to fight against this ant and against the symbiotic fungus, Leucocoprinus gongylophorus (Heim) . Moeller. Methods used and presented in this work aIIowed to observe effects of selected plant uses on mortality and insect's behavior. The protocols performed were selected for their potentiality to detect the different types of insecticidal effects (contact toxicity, repellent effect, toxicity by ingestion, fungicidal or fungistatic). Six traditional plant uses of five plants were tested on the ant : Mammea americana L., Nerium oleander L., Nicotiana tabacum L.,Rollinia mucosa (Jacq) Baill. and Trichilia pallida Sw.Five other plants uses were tested on the fungus:Allium cepa L.,Lycopersicon esculentum Mill.,Manihot esculenta Crantz and Senna alata (L.) Roxb.The obtained résults provide us with some interesting trails to fight against this pest
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Zogo, Mahugnon Barnabas. "Impact entomologique de stratégies complémentaires de lutte intégrée contre le paludisme dans un contexte de résistance des vecteurs aux insecticides au nord de la Côte d’Ivoire." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTT056.
Abstract:
L’expansion de la résistance des vecteurs aux pyréthrinoïdes et le ralentissement des progrès obtenus récemment dans la lutte contre le paludisme en Afrique mettent en exergue le besoin urgent de déployer des stratégies complémentaires aux moustiquaires imprégnées d’insecticide à longue durée d’action (MILDA) pour accélérer la réduction du poids de la maladie. Les stratégies telles que le renforcement de l’Information, l’Education et la Communication (IEC), les pulvérisations intradomiciliaires (PID) et la lutte anti-larvaire (LAL) à base du Bacillus thuringiensis isralensis (Bti) sont disponibles mais le réel bénéfice de leur utilisation en combinaison aux MILDA reste à démontrer. L’objectif principal du présent travail a été de mesurer l’impact additionnel de ces trois stratégies sur la transmission des Plasmodium spp. à travers un essai contrôlé randomisé mené dans 28 villages du district sanitaire de Korhogo, au Nord de la Côte d’Ivoire, une zone de résistance des vecteurs aux pyréthrinoïdes. En amont du déploiement de ces interventions, mon travail de thèse a d’abord permis 1) l’étude de l’efficacité d’une nouvelle formulation de larvicide en conditions semi-contrôlées ; 2) l’étude de la bionomique des anophèles vecteurs, des mécanismes de résistance aux insecticides et de la transmission des Plasmodium spp et 3) l’identification et la caractérisation des gîtes larvaires d’anophèles dans la zone d’étude. Le suivi post-intervention a permis de montrer 1) une réduction de la densité agressive des vecteurs (69%) cinq mois après le démarrage de la stratégie IEC, de l’indice sporozoïtique (84%) et du TIE (86%) dans le bras MILDA + IEC par rapport au bras MILDA seules ; 2) une réduction de la densité agressive des vecteurs deux mois (72%) et quatre mois (69%) après la mise en place de la PID puis du TIE (62%) dans le bras MILDA + PID par rapport au bras MILDA seules ; 3) une réduction de la densité agressive des vecteurs (95%) trois mois après le démarrage de la LAL et du TIE (88%) dans le bras MILDA + LAL par rapport au bras MILDA seules. Ces résultats montrent que les stratégies IEC, PID et LAL sont des stratégies complémentaires efficaces pour réduire l’intensité de la transmission à Korhogo. L’analyse des données épidémiologiques de l’essai permettra de mieux apprécier le bénéfice additionnel de ces stratégies sur le poids du paludismeThe spread of pyrethroid resistance in malaria vectors and the stalling of recent progress in malaria control in Africa highlight the urgent need to deploy complementary strategies to long-lasting insecticidal nets (LLINs) to accelerate the reduction in the disease burden. Strategies such as strengthened Information, Education and Communication (IEC), Indoor Residual Spraying (IRS) and larviciding with Bacillus thuringiensis isralensis (Bti) are available but the actual benefit of their use in combination with LLINs remains to be demonstrated. The main objective of this work was to measure the additional impact of these three strategies on malaria transmission through a randomized controlled trial run in 28 villages in the health district of Korhogo, northern Côte d’Ivoire, an area of vector resistance to pyrethroids. Prior to the deployment of these strategies, my work allowed us to 1) assess the efficacy of a new larvicide formulation under semi-field conditions; 2) study vector bionomics, insecticide resistance mechanisms and malaria transmission; 3) identify and characterize Anopheles spp. breeding habitats in the study area. Data from post-intervention surveys showed 1) a reduction of vector density (69%) five months after the beginning of the IEC strategy, of sporozoïte rate (84%) and of IER (86%) in the LLIN+IEC arm relative to the LLIN alone arm; 2) a reduction of vector density at months two (72%) and four post-IRS (69%) and of EIR (62%) in the LLIN+IRS arm relative to the LLIN alone arm; 3) a reduction of vector density (95%) three months after the beginning of larviciding intervention and of IER (88%) in the LLIN + larviciding arm relative to the LLIN alone arm. These results provide evidence that IEC, IRS and larviciding are effective complementary strategies to reduce transmission intensity in Korhogo. Analysis of epidemiological data collected during the trial will allow a better understanding of the additional benefit of these strategies on the malaria burden
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Damien, Barikissou Georgia. "Evaluation épidémiologique de l’efficacité des stratégies de lutte anti-vectorielle contre le paludisme dans un contexte de lutte intégrée." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTT044/document.
Abstract:
Malgré les efforts national et international pour contrôler le paludisme, de nombreux pays d’Afrique Sub-saharienne restent à risque d’infection, de morbidité et de décès liés au paludisme. L’objectif de cette thèse est d’évaluer l’efficacité « théorique » et l’efficacité « réelle » des outils de la lutte anti-vectorielle (LAV) en utilisant des indicateurs parasitologiques et cliniques. Pour évaluer l’efficacité « théorique » d’une mesure de LAV (étude expérimentale), il faut effectuer un essai contrôlé randomisé à unité de randomisation collective. L’évaluation de l’efficacité « réelle » des outils de LAV est possible grâce à l’utilisation d’un essai contrôlé randomisé à condition que le groupe témoin soit couvert au minimum par les moustiquaires imprégnées d’insecticide à longue durée d’action (MILD) de référence ou les outils de LAV déjà en utilisation dans la population d’étude. Mais, elle nécessite d’énormes moyens techniques, logistiques et financiers. Les résultats de cet essai ont permis de noter que ni la couverture universelle en MILD, ni les combinaisons de MILD+Pulvérisation intra-domiciliaire (PID) ou de MILD+bâches imprégnées d’insecticides n’ont pas apporté une protection supplémentaire contre l’infection et l’accès palustre non compliqué (APNC) par rapport à la MILD en couverture sélective. L’évaluation de l’efficacité réelle des outils de LAV en post-distribution requiert un type d’étude épidémiologique plus souple dans la faisabilité. Face aux contraintes éthiques et financières de l’étude longitudinale, nous avons validé l’utilisation d’une étude cas-témoin à cet effet. Elle a été réalisée en premier chez les enfants de 0-5 ans puis appliquée à toute la population. Les résultats obtenus indiquent que l’efficacité des MILD est variable d’une région à l’autre. En zone rurale, les MILD ont conféré sur l’APNC une efficacité de 40-50 % en ouverture sélective en MILD chez les enfants de zéro à cinq ans. Une réduction de 49 % des APNC a été notée dans toute la population si les MILD (en couverture universelle) sont associées à la PID. En zone urbaine, les MILD en couverture universelle n’ont pas permis de réduire le nombre d’APNC dans toute la population. Elles ont cependant permis une réduction de 50 % des infections palustres dans un seul quartier de la zone d’étude. Les limites de cette étude cas-témoin peuvent être intrinsèques aux mesures de lutte (défaut de couverture, résistance des vecteurs aux insecticides etc.). La mesure de l’exposition peut également être soumise à des biais. Plusieurs facteurs interférant avec la réussite de la LAV ont été évoqués. Le premier facteur défavorable à l’efficacité de la MILD est son défaut d’utilisation. De même, la description de la pièce où se joue la LAV montre que l’espace disponible pour que tous les acteurs puissent jouer convenablement leur rôle (MILD, PID, Homme et vecteur) est assez restreint. Cet espace est souvent mal éclairé. De même la présence des flammes libres participe à la dégradation de l’intégrité physique des MILD. La présence de trous sur les moustiquaires indique une perte de leur efficacité car à partir d’un certain indice > 100, les individus sont fortement exposés aux piqûres de vecteurs. En plus, An. funestus, un des principaux vecteurs assurant la transmission dans les zones d’études concernées peut piquer au-delà de 6 h du matin et assure une bonne partie de la transmission à l’extérieur des habitations. Enfin, les moustiquaires peuvent également créer des dommages corporels à partir d’incendie auxquelles elles participent de part leur caractère inflammable. A l’étape actuelle de la lutte contre le paludisme, il est nécessaire de trouver de meilleurs outils pour améliorer la qualité de la prévention par la LAV. La recherche opérationnelle nous semble en outre primordiale dans la mesure où les outils de LAV utilisés à large échelle ont déjà fourni de bons résultats d’efficacité au laboratoireDespite national and international efforts, malaria remains a major public health in many countries. Health systems are hindered by the lack of information on the actual burden of malaria and the effectiveness of vector control tools. Vector-control measures are a component of integrated malaria control strategies. The objective of our thesis was to evaluate the efficacy and the effectiveness of malaria vector control tools using parasitological and clinical criteria.With a block randomized control trial, we investigated whether the combination of long-lasting insecticidal mosquito nets (LNs) with indoor residual spraying (IRS) or Carbamate-treated Plastic Sheeting (CTPS) conferred better protection against malaria vectors than did LNs alone. The clinical incidence density of malaria was not reduced in the children from the "Universal LN" group (incidence density rate (0.95, 95% CI 0.67–1.36, p=0.79), nor in those from the "Target LN + IRS" group (1.32, 0.90–1.93, p=0.15) or from the "Universal LN + CTPS group (1.05, 0.75–1.48, p=0.77) compared with the reference group "Target LN". The same trend was observed with the prevalence and parasite density of asymptomatic infections. The evaluation of the effectiveness of vector control tools is possible but requires enormous technical, logistic and financial resources. The evaluation of the effectiveness of malaria vector control tools after distribution requires a more flexible epidemiological study. Considering the ethical and financial constraints of the longitudinal study, we validated the use of a case-control study to this purpose. It was conducted primarily among children aged 0-5 years old and then applied to the entire population. Results were spatial dependant when taking into account age and compliance to chemoprophylaxis as confusion factors, use of other vector control tools, sex, and economic status, school level of the mother or the head of the house. In the rural area, the use of LNs provided significant level of protection (40-50%) against clinical cases among children aged 0-5 years old. This significant protection was obtained among all population only if the LNs were associated to IRS. In the urban area, the use of LN was not provided protection against clinical cases but reduce 50% of the risk of Plasmodium falciparum infection in one neighbourhood. The limits of this case-control study may be intrinsic to control measures (lake of coverage, vector resistance to insecticides etc.). The exposure of vector control tools measures may also be subject to bias. Several factors interfering with the success of malaria control were discussed. The first negative factor to the effectiveness of vector control tools was the "no use of LNs". Then follows the immediate environment where the fight against vectors took place. The description of the room where played vector control fighting shows that the space available for all the actors (LNs, IRS, humans and vectors) to play their role properly is quite limited. This space is often poorly enlightened. Similarly the presence of open flames is involved in the degradation of the physical integrity of LNs. The presence of holes on the bed-nets indicates a loss of effectiveness because from a hole index above 100, individuals are highly exposed to the bites of vectors. In addition, An. funestus, one of the main vectors of malaria transmission in the study area, bitted after 6:00 am and provides much of the transmission in outdoor. Finally, the nets can also create personal injury as fire. At the end our work, we conclude that the innovative vector control tools are required to improve malaria vector control. But, operational research seems now essential as the vector control tools used on a large scale have provided good efficacy results in the laboratory. The challenge then is to obtain comparable results in real condition of use and look for effectiveness barriers
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Kesteman, Thomas. "Evaluation de l'efficacité des actions de lutte antipaludique à Madagascar." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM5043.
Abstract:
Afin de guider les politiques de santé publique, il semble intéressant de vérifier l’efficacité des actions de lutte contre le paludisme (ALP). Pour ce faire, l’on tend à évaluer l’impact d’une ALP sur l’incidence de la maladie par exemple, mais cette approche permet difficilement d’isoler l’effet d’une ALP par rapport aux autres interventions déployées simultanément, et par rapport aux interférences environnementales et sociales. La modélisation mathématique est également d’un recours limité puisqu’elle établit des inférences à partir de l’efficacité théorique de l’intervention (efficacy en anglais) mesurée au cours d’essais contrôlés. La mesure directe de l’efficacité de l’intervention sur le terrain (effectiveness en anglais), c’est-à-dire sous l’influence de facteurs biologiques, environnementaux et humains, est cependant possible. En particulier, des enquêtes épidémiologiques appropriées permettent de mesurer l’association entre l’exposition aux ALP et le poids du paludisme.Dans le cadre de cette thèse, plusieurs études de ce type ont été menées pour évaluer l’effectiveness des ALP à Madagascar. Ce pays a l’avantage de présenter un contraste important en terme de transmission du paludisme, certaines parties étant en phase de pré-élimination et d’autres présentant une transmission du paludisme intense et continue. (...)Ce travail de thèse propose une méthodologie d’évaluation de l’effectiveness des ALP transposable dans d’autres contextes, et démontre l’utilité de cette approche. Dans un contexte mondial où les financements internationaux stagnent, ces résultats apportent des informations et outils utiles pour poursuivre la lutte contre le paludismeIn order to guide policy making in public health, it seems useful to confirm the effectiveness of malaria control interventions (MCI). To achieve this, one may evaluate the impact of a given MCI on the incidence of the disease, for example, but this approach won’t easily disentangle the effects of the intervention from those of other MCIs deployed simultaneously, and from influences of environmental and social factors. Mathematical modelling won’t be helpful in this purpose since it infers the impact from the efficacy measured in controlled trials. The direct estimation of the effectiveness of the intervention under fields conditions, i.e. under the influence of biological, environmental and human factors, is nevertheless possible. In particular, appropriate epidemiological surveys can estimate the association between exposure to MCIs and malaria.The present thesis describes the results of several studies conducted to evaluate the effectiveness of MCIs in Madagascar. This country has the advantage to include constrasted malaria transmission patterns, with areas earmarked for pre-elimination and others with intense and perennial malaria transmission. (...)Overall this thesis proposes a methodology for the evaluation of the effectiveness of MCIs that can be transferred to other settings, and demonstrates the usefulness of this approach. In a global context of stagnating international funding, these results provide valuable information and tools to carry on the fight against malaria
33
Bafalimanana, Halitiana Josea. "Evaluation des effets d'insecticides sur deux types d'Hyménoptères auxiliaires des cultures, l'abeille domestique (Apis mellifera L. ) et des parasitoi͏̈des de pucerons : études de terrain à Madagascar et de laboratoire en France." Paris, Institut national d'agronomie de Paris Grignon, 2003. http://www.theses.fr/2003INAP0001.
Abstract:
Les abeilles et les parasitoi͏̈des de pucerons courent le risque d'exposition à des insecticides qui ne leur sont pas destinés. Nos objectifs consistent à évaluer ce risque sur le terrain et à contribuer à mettre au point des tests de toxicité létale et sublétale en laboratoire pour les deux types d'insectes. A Madagascar, nous avons mené une enquête pour déterminer l'impact de pratiques paysannes en matière de protection de cultures d'agrumes sur les abeilles, et une expérimentation en parcelle de choux pour évaluer les effets de traitements insecticides sur les Hyménoptères parasites de pucerons. En France, nous avons déterminé en laboratoire les toxicités aigue͏̈s de la deltaméthrine, de la lambda cyhalothrine, du chlorpyriphos éthyle et du pyrimicarbe, pour les abeilles et le parasitoi͏̈de de pucerons, Aphidius ervi. Nous avons analysé, chez l'abeille, certaines causes de variabilité des doses létales à 50%. Nous avons également déterminé les effets d'insecticides sur le comportement d'orientation olfactive en olfactomètre chez l'abeille et A. Ervi. A Madagascar, le traitement pendant la floraison existe et les apiculteurs constatent des effets négatifs sur leurs ruches. L'expérimentation en parcelle de chou montre que le traitement insecticide contribue à retarder l'action des Hyménoptères parasites de pucerons. En laboratoire, la toxicité varie en fonction du mode de pénétration et de la nature des matières actives. Chez l'abeille, les toxicités par ingestion collective et individuelle ne sont pas toujours comparables. L'importance du phénomène de trophallaxie dans cette différence a été précisée. Ainsi, la valeur de DL50 exprimée en ng/abeille dépend des conditions expérimentales. Les abeilles et A. Ervi ayant survécu aux traitements insecticides et testés en olfactomètre, ne montrent pas ou peu de changement de comportement d'orientation vis-à-vis de l'odeur utilisée. Par contre, les abeilles recevant des DL20 et DL50 de deltaméthrine ont une capacité locomotrice réduite. Cette perturbation pourrait avoir des effets non négligeables sur les insectes auxiliaires dans un environnement pollué par les insecticidesHoneybees and aphid parasitoids may suffer from side effects of insecticides during their beneficial activity. Our objective was the risk assessment of pesticides towards these non target insects in the field and a contribution to the setting up of lethal and sublethal toxicity tests in the laboratory. In Madagascar, we conducted an investigation to define the impact of crop protection farmers' practices on honeybees, and we conducted an experimentation to estimate the effects of a treatment on aphid parasitoids. In France, we determined the acute toxicity of deltamethrin, lambda cyhalothrin, chlorpyrifos ethyl and pirimicarb, on the honeybee and on an aphid parasitoid, Aphidius ervi. We analyzed some parameters responsible for the variability of lethal dose 50 (LD50) values. We also investigated the effects of the insecticides on orientation responses of the honeybee and A. Ervi, using a common behavioral test, the four-armed olfactometer. In Madagascar, insecticide treatment can occur during blooming and the farmers have observed negative effects on honeybee colonies. With regard to Hymenopterous parasitoids, we found out that the insecticide treatment contributes to delay their action in experimental cabbage field plots. In laboratory conditions, the toxicity varies according to the exposure route and to the active ingredient. The honeybee oral toxicity differed between collective and individual administration. The role of trophallactic interactions in the distribution of the active ingredient was evaluated. Thus, value of LD50 expressed in ng/bees varies according to the experimental conditions. The honeybees and A. Ervi surviving the insecticide treatments showed no or little effect in their attraction responses in the four-armed olfactometer. On the other hand, in honeybees, LD20 and LD50 of deltamethrin decreased their capability to move. These perturbations might have an important effect on beneficials insects in an environment contaminated by pesticides
34
Clark, L. J., and E. W. Carpenter. "Insecticide Evaluation Studies, Safford Agricultural Center, 1999-2000." College of Agriculture, University of Arizona (Tucson, AZ), 2001. http://hdl.handle.net/10150/211302.
Abstract:
Three studies were conducted over the two year period to explore the effectiveness of using pyrethroid insecticides only vs. rotating insecticide chemistries between the pyrethroids and organophosphates on both long and short staple cotton varieties. These same treatments were also evaluated over Bt and non-Bt varieties. In the worst case scenario, where weather conditions prevented timely application of insecticides and effectiveness of insecticides applied, long staple cotton yielded around 1/3 bale per acre after six insecticide applications. Within 200 feet of this experiment, during the same cropping season, with the same insecticides applied, DP 90B (a Bt variety) produced 3 bales per acre. Details of these studies are contained in this report.
35
Beaufour, Martine Nicole Hélène. "Evaluation des [delta]2-oxazolines-1,3, des [delta]2-thiazolines-1,3 et des [delta]2-imidazolines-1,3 comme proinsecticides d'acides carboxyliques : suivis de la métabolisation dans les milieux biologiques d'insectes par RMN et chromatographie : réactivité particulière des imidazolines vis-à-vis du DNBF." Versailles-St Quentin en Yvelines, 2002. http://www.theses.fr/2002VERS002V.
Abstract:
Une évaluation de l'activité biologique des proinsecticides a été réalisée au moyen de tests par contact sur acariens, drosophiles et pucerons ainsi que de tests par ingestion sur chenilles. Ainsi, les résultats sont ressortis : certaines oxazolines se comportent effectivement comme des proinsecticides d'acides carboxyliques, les thiazolines se révélant finalement être également des proinsecticides en présence de corps gras. Par contre, les imidazolines se sont montréées stables. En ce qui concerne l'impact de la chiralité, aucune énantiosélectivité n'a été décelée jusqu'ici, pour les deux volets activité biologique et démasquage. Lors de testes biologiques sur couches de pucerons soit sensibles, soit résistants aux insecticides classiques, une remarquable sélectivité puceron/puceron a été mise en évidence pour les oxazolines
36
Ellsworth, Peter C., Brian Deeter, and Mike Whitlow. "EUP Evaluation of a Novel Insecticide for Lygus Control." College of Agriculture, University of Arizona (Tucson, AZ), 1999. http://hdl.handle.net/10150/197261.
Abstract:
Lygus became the number one pest of cotton in 1998 with statewide losses of over $16 million in spite of individual costs to the grower of over $55/A for control. Selective technologies for whitefly and pink bollworm control reduce the number of broad spectrum sprays that incidentally control Lygus. Control of Lygus depends mainly on just two related chemical classes of insecticides, organophosphates and carbamates. Over reliance on such a limited diversity of chemical controls increases the risk of resistance. Further, FQPA threatens the future availability of many of our main stay chemical controls. The study reported here sought to investigate the commercial suitability of a new compound, Regent®, for the control of Lygus. This novel mode of action represents one of the few potential new tools under development for Lygus management. Under a federal Emergency Use Permit (EUP), Regent was tested against two standards of Lygus control (Orthene® and Vydate®) and an untreated check. In a test of unusually high Lygus densities, Regent provided excellent control of small (instars 1–3) and large (instars 4–5) Lygus nymphs and may provide marginally better control of adults than current standards. None of the tested agents provided quick control or knockdown of adults. Rather, adult levels were reduced over time, most likely as a result of prevention of the development of new adults via nymphal control. All three materials protected cotton producing yields significantly higher than the check. The Orthene treatment had the highest yield, though not significantly higher than the Regent treatment which was effectively sprayed one less time than the other compounds.
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Rafalimanana, Halitiana Joséa. "Evaluation des effets d'insecticides sur deux types d'Hyménoptères auxilliaires des cultures, l'abeille domestique (Apis mellifera L.) et des parasitoïdes de pucerons : études de terrain à Madagascar et de laboratoire en France." Phd thesis, INAPG (AgroParisTech), 2003. http://tel.archives-ouvertes.fr/tel-00005703.
Abstract:
Les abeilles et les parasitoïdes de pucerons courent le risque d'exposition à des insecticides qui ne leur sont pas destinés. Nos objectifs consistent à évaluer ce risque sur le terrain et à contribuer à mettre au point des tests de toxicité létale et sublétale en laboratoire pour les deux types d'insectes. A Madagascar, nous avons mené une enquête pour déterminer l'impact de pratiques paysannes en matière de protection de cultures d'agrumes sur les abeilles, et une expérimentation en parcelle de choux pour évaluer les effets de traitements insecticides sur les Hyménoptères parasites de pucerons. En France, nous avons déterminé en laboratoire les toxicités aiguës de la deltaméthrine, de la lambda cyhalothrine, du chlorpyriphos éthyle et du pyrimicarbe, pour les abeilles et le parasitoïde de pucerons, Aphidius ervi. Nous avons analysé, chez l'abeille, certaines causes de variabilité des doses létales à 50%. Nous avons également déterminé les effets d'insecticides sur le comportement d'orientation olfactive en olfactomètre chez l'abeille et A. ervi.
A Madagascar, le traitement pendant la floraison existe et les apiculteurs constatent des effets négatifs sur leurs ruches. L'expérimentation en parcelle de chou montre que le traitement insecticide contribue à retarder l'action des Hyménoptères parasites de pucerons.
En laboratoire, la toxicité varie en fonction du mode de pénétration et de la nature des matières actives. Chez l'abeille, les toxicités par ingestion collective et individuelle ne sont pas toujours comparables. L'importance du phénomène de trophallaxie dans cette différence a été précisée. Ainsi, la valeur de DL50 exprimée en ng/abeille dépend des conditions expérimentales. Les abeilles et A. ervi ayant survécu aux traitements insecticides et testés en olfactomètre, ne montrent pas ou peu de changement de comportement d'orientation vis-à-vis de l'odeur utilisée. Par contre, les abeilles recevant des DL20 et DL50 de deltaméthrine ont une capacité locomotrice réduite. Cette perturbation pourrait avoir des effets non négligeables sur les insectes auxiliaires dans un environnement pollué par les insecticides
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Kulkarni, Manisha A. "Entomological evaluation and insecticide resistance monitoring of malaria vectors in Tanzania." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111839.
Abstract:
Insecticide-treated nets (ITN) are an effective tool to reduce the burden of malaria in Africa. To address questions concerning the sustained impact of ITN in the face of changing transmission intensity and spreading insecticide resistance a series of four entomological investigations was undertaken in Tanzania.First, a longitudinal survey of vector populations at different altitudes was conducted in the Hai District, Kilimanjaro Region, Tanzania. Entomological parameters relevant to malaria transmission were measured. Vector densities and entomological inoculation rates decreased dramatically with increasing altitude. Seasonal variations in the host preference and resting behaviour of Anopheles arabiensismay influence malaria transmission and control.
Second, the insecticide susceptibility status of vector populations from agricultural sites in the Kilimanjaro Region was evaluated. Malaria vectors from six sites were highly susceptible to diagnostic concentrations of pyrethroid insecticides and DDT in susceptibility tests. Permethrin tolerance in populations of An. arabiensis from an irrigated rice-growing area was not directly related to agricultural use of insecticides. Synergist bioassays indicated the contribution of a metabolic oxidase-based mechanism to the observed resistance while the knockdown resistance (kdr) mechanism was not detected. Close monitoring of resistance development in this area is needed.
Third, the biological efficacy of ITN and the insecticide susceptibility status of mosquito populations from areas with long-term use of ITN were investigated. Data were compiled from national surveys and long-term ITN projects to examine trends in resistance development in Tanzania. Anopheles species were highly susceptible to ITN and diagnostic concentrations of pyrethroid insecticides, while 'nuisance-biting' Culex quinquefasciatus displayed low susceptibility to these compounds. Low efficacy of ITN against C. quinquefasciatus has implications for user acceptance of ITN.
Finally, a novel method for kdr genotyping was developed and evaluated. Sequence specific oligonucleotide probes (SSOP) were used to identify kdr mutations in Anopheles gambiae s.l. in a high-throughput enzyme-linked immunosorbent assay (ELISA) format. Evaluation of the method on field-collected specimens detected the leucine-phenylalanine kdr mutation in two individual An. arabiensis, raising implications for the geographic spread of kdr-based resistance. The novel SSOP-ELISA method is a useful tool for high-throughput screening allowing sensitive detection of insecticide resistance.
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Kerns, David L., and Tony Tellez. "Evaluation of Insecticide Applications for Citrus Thrips Control Under Hot Conditions." College of Agriculture, University of Arizona (Tucson, AZ), 2002. http://hdl.handle.net/10150/226071.
Abstract:
A small plot efficacy trial was conducted evaluating citrus thrips control under hot conditions. Average daily maximum temperatures ranged from the mid-90’s to low 100°F’s. Success and Carzol were the most efficacious products evaluated, followed by Lorsban and Dimethoate. Both Lorsban and Dimethoate provided good initial thrips control but were short lived. Lorsban appeared to have a slightly longer residual than Dimethoate. Both of the pyrethroids, Baythroid and Danitol, performed poorly. Neither provided good thrips knockdown or residual control. Pyrethroids should be avoided for thrips control when temperatures equal or exceed 95°F. We were not able to demonstrate any adverse effect on efficacy towards thrips by acidifying Success. However, Success is not prone to hydrolysis at high pHs, and acidification is not necessary or advised.
40
Palumbo, John, Clayton Jr Mullis, Francisco Reyes, and Andreas Amaya. "Evaluation of Foliar Insecticide Approaches for Aphid Management in Head Lettuce." College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/221644.
Abstract:
Provado insecticide (imidacloprid) was compared to Admire and other standard insecticides for management of aphids in head lettuce in Yuma 1995 and 1996. Foliar applications of Provado appear to provide an alternative method of controlling aphids on lettuce comparable to prophylactic applications of Admire. The prevention of aphid colonization in lettuce heads with Provado may depend greatly on the timing and frequency of applications before harvest occurs. These studies and other studies on spinach suggest that more than one application of Provado will be necessary to adequately suppress aphid contamination in heads. The label suggests that applications be timed 5-7 apart. Our data tends to support this recommendation. Furthermore, timing applications should be based on days to harvest, level of aphid colonization and duration of aphid migration.
41
Magbity, Edward Brima. "Methods for entomological evaluation of treated bed nets." Thesis, London School of Hygiene and Tropical Medicine (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324915.
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Brownlow, Andrew C. "Evaluation of a novel method for controlling bovine trypanosomiasis." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/4930.
Abstract:
The problem of controlling tsetse flies in Africa is an old one. The tsetse fly transmits the trypanosome parasites which cause sleeping sickness in humans and disease in cattle. Because cattle are a favoured food source for tsetse much work has been done looking at the use of insecticide treated cattle as a control strategy for the tsetse fly. Such treatment methods possess many advantages; they are safe and relatively environmentally benign, they can be applied by individual farmers without the need for logistically demanding and costly traditional control programmes and, in addition to tsetse flies the insecticides are effective against a wide range of other harmful cattle parasites. The cost of the insecticide is however a significant constraint to the number of livestock keepers who can afford to employ the technique and as a result many cattle remain untreated. Following the discovery that tsetse had a significant predilection for feeding on the legs and belly of cattle, it was hypothesised that restricting the insecticide to only those areas could offer comparable protection to treating the whole animal. Such an approach would use up to 80% less drug and thus make the treatment per animal much cheaper. In addition, preferentially targeting areas favoured by tsetse, and leaving the rest of the animal untreated, preserves some important ecological balances between cattle and their parasites which traditional treatment methods destabilise. This thesis describes the design, implementation and analysis of a longitudinal study run over 8 months in south east Uganda that sought to compare the effect of applying insecticide to cattle only on the regions favoured by tsetse flies. Cattle were recruited to the study and assigned one of four treatment groups; a whole body application of deltamethrin insecticide pour-on; a restricted application of deltamethrin spray, applied to the front legs, ears and belly; a prophylactic trypanocide injection of isometamidium chloride, and a control group, that received no further treatments. All animals in the study were however cleared using twin doses of a trypanocide diminazene aceturate at the start of the study.
43
Duthie, Marnie A. "Evaluation of a neem-based insecticide for control of the mountain pine beetle." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24124.pdf.
44
Moore, David Joseph II. "Evaluation of Multiple Insecticidal Products for Control of the Common Bed Bug (Cimex lectularius (L.))." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/76923.
Abstract:
The common bed bug has reemerged as a major pest in the United States. Pest management professionals need reliable up-to-date information on how to manage bed bug infestations. My study was intended to evaluate the efficacy of several insecticides currently labeled for bed bug control.
In product efficacy tests, field strain bed bugs were found to be 99-450 times less susceptible than laboratory strain bed bugs to several pyrethroid products. The non-pyrethroid products tested, chlorfenapyr and a non-toxic desiccant dust, killed laboratory strain bed bugs, but were extremely slow acting taking greater than 9 days to kill 50%. None of the insecticides tested, including the pyrethroids, were repellent to laboratory or field strain bed bugs.
A field test was conducted comparing 2 pesticide treatments regimens (traditional and novel) for bed bug control in low income apartments. Both the traditional and novel combinations caused significant reductions in bed bug populations. Both treatments reduced the number of bed bugs by the end of the test period, but neither treatment combination completely eliminated the bed bug infestations, even after an average of 1.3 gallons of product was applied in each apartment.
Laboratory assays were conducted to determine the effect of hydroprene exposure on bed bug development. Although hydroprene did not appear to interfere with nymphal development, fifty percent of the bed bugs died during the final molt. The bed bugs which survived to adulthood showed no reduction in fecundity when compared to control groups.Master of Science in Life Sciences
45
Dierks, Cole. "Evaluating the Efficacy of Foliar Insecticide and Soybean Seed Treatment in South Dakota." Thesis, South Dakota State University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13864072.
Abstract:
The utilization of cover crops and no-till practices are important for the conservation of both soil and moisture in South Dakota. However, it is unknown if these practices impact the efficacy of insecticide seed treatments. In soybean, insecticide seed treatments are used prophylactically to prevent potential crop losses from early season insect pests. The prophylactic use of any management strategy increases the likelihood for selection pressure and also represents unnecessary input costs. The purpose of the research conducted for Chapter 2 was to determine the impact that tillage systems, cover crops and planting populations have on the efficacy of insecticide seed treatments. Two years of field data was collected from established long-term tillage and cover crop rotation plots at the South Dakota State University Southeast Research Farm. During each year, four factors were evaluated for their impact on yield (i.e., tillage, cover crop, seeding rate and seed treatment). Stand counts, soil samples and yield data were taken from each plot. In Chapter 3, we evaluated pyrethroid resistance in soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae) populations in South Dakota. In 2015, the University of Minnesota discovered populations of the soybean aphid that were partially resistant to pyrethroid insecticides. Due to the soybean aphid’s capacity for rapid reproduction and its ability to travel long distances in its alate (i.e., winged) form, it was determined that South Dakota may have resistant populations present. In 2017 and 2018, an efficacy study was deployed at three locations, over two years throughout Eastern South Dakota. A total of eight foliar insecticides were used in 2017 and 10 foliar insecticides in 2018. The results from chapter 2 indicate that seed treatment and cover crops have no significant impact on soybean yield. The results from chapter 3 determined that pyrethroid resistant soybean aphids are present in South Dakota.
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Kharel, Kabita. "Evaluation of pyrethrin aerosol insecticide as an alternative to methyl bromide for pest control in flour mills." Thesis, Kansas State University, 2013. http://hdl.handle.net/2097/16006.
Abstract:
Master of ScienceDepartment of Entomology
Frank H. Arthur
Kun Yan Zhu
Experiments were conducted to assess the effects of direct and indirect exposure scenarios, different degrees of residual flour, open and obstructed positions, and seasonal temperature variations on the efficacy of synergized pyrethrin against the red flour beetle, Tribolium castaneum (Herbst) and the confused flour beetle, Tribolium confusum Jacquelin du Val. To evaluate effects of direct and indirect exposures of T. castaneum and T. confusum eggs, larvae, pupae, or eggs to the insecticide aerosol within a flour mill, the following treatments were made to each life stage: insects treated with aerosol and transferred to treated or untreated flour, untreated insects transferred to treated flour, and insects and flour combined and treated together. Different degrees of harborage or sanitation levels were created by exposing T. confusum larvae, pupae, and adults to pyrethrin aerosol in Petri dishes containing 0, 0.1, 1, 5, and 10 g of wheat flour. Effects of pyrethrin dispersal in open and obstructed positions and seasonal temperature variations were assessed by exposing T. confusum pupae and adults in open positions and inside wooden boxes (1 m long, 20 cm wide, and 5, 10, or 20 cm high) inside experimental sheds maintained at target temperatures of 22, 27, and 32 °C. Results showed that when T. castaneum and T. confusum were directly exposed to aerosol without the flour source, or with a low amount of flour at open exposed areas, the aerosol provided good control against all life stages of T. castaneum and T. confusum. However, when insects were indirectly exposed (treated together with flour or untreated insects were transferred to treated flour), or treated together with deeper flour amounts, and exposed inside the boxes, the efficacy was greatly reduced. Eggs and pupae of both the species were more susceptible compared to larvae and adults. Additionally, the moribund adults initially observed in indirect exposure treatments, or at the deeper flour depth and exposure positions insides the boxes, were better able to recover. Generally, temperatures in the range of 22-32 °C had no significant effects on overall efficacy of pyrethrin aerosol.
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Raeppel, Caroline. "Evaluation de la contamination des atmosphères intérieures et extérieures induite par les usages non agricoles de pesticides." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00869960.
Abstract:
Dans le but d'évaluer la contamination des atmosphères intérieures et extérieures induite par les usages non agricoles de pesticides, deux approches complémentaires ont été mises en oeuvre : l'utilisation de capteurs passifs de type Tenax TA pour réaliser des prélèvements d'air, et l'utilisation de cheveux employés comme biomarqueurs d'exposition. Des campagnes de mesures ont été menées sur plusieurs sites à la suite de traitements de désherbage ou de désinsectisation ainsi quedans des logements. Les échantillons d'air et de cheveux ont été extraits respectivement par thermodésorption et par extraction solide-liquide, avant d'être analysés en chromatographie gazeuse couplée à la spectrométrie de masse (GC-MS). Une augmentation du niveau de contamination de l'air extérieur et intérieur et l'existence de transferts entre ces deux milieux ont pu être observées après l'application de pesticides. Dans les logements, des pesticides actuellement employés mais aussi des pesticides interdits et persistants ont été détectés. Plusieurs pesticides ont également été détectés dans les cheveux, mais l'exposition humaine à ces derniers n'a pas pu toujours être corrélée à une contamination de l'air.
48
Saddler, Adam. "Evaluating insecticide-resistance in the malaria vector Anopheles gambiae and its implications for malaria transmission." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/24434.
Abstract:
Insecticide resistance, in the mosquito vector, threatens the efficacy of current methods to control malaria. Yet evidence of control failure due to insecticide resistance is sparse, despite over 50 years since resistance was identified in the mosquito. In this thesis, laboratory experiments with mosquitoes, as well as mathematical modelling, are used to improve our understanding of how insecticide resistance might impact malaria transmission. Firstly, demographic and environmental effects on the phenotypic expression of resistance are investigated. Decreasing expression of resistance with age and malaria infection, suggest resistance may not be as large a problem as once believed. Further factors that affect the phenotypic expression of resistance, such as infection by the microsporidian Vavria culicis and quantity of larval food, suggest that the phenotypic expression of resistance may even be manipulated to reduce its impact on disease transmission. Secondly, costs of resistance are explored as they may reduce the ability of a mosquito to transmit malaria. It is demonstrated that, under environmental stress from parasites, costs to longevity can be increased. Mosquito longevity is a key parameter in malaria transmission so any reduction in longevity, due to costs of resistance, will reduce the ability of the mosquito to transmit malaria. Finally, the thesis examines if the behavioural avoidance of insecticides can be changed through environmental manipulation. In summary, the phenotypic expression of resistance and the costs of resistance are two factors that will determine the threat insecticide-resistance poses to malaria control. It is demonstrated, in the laboratory, that these two factors can vary due to environmental and demographic factors, but to fully understand the threat of resistance these ideas have to be investigated in the field.
49
ALIX, ANNE. "Evaluation de l'efficacite parasitaire de trybliographa rapae w. (hymenoptera : figitidae), utilise en association avec le chlorfenvinphos dans la perspective d'une lutte integree contre la mouche du chou delia radicum l. (diptera : anthomyiidae) (doctorat : biologie et sciences de la sante)." Rennes 1, 2000. http://www.theses.fr/2000REN1B052.
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Che, Mendoza A. "Evaluation of impact of long-lasting insecticidal house screening (LLIS) on pyrethroid resistant population of the dengue vector Aedes aegypti in Mexico." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3004265/.
Abstract:
The public health importance of the endophilic mosquito Aedes aegypti has increased dramatically in the recent decade, because it is the vector of current outbreaks of dengue, chikungunya, Zika and Yellow fever viruses. The use of long-lasting insecticide nets fixed on doors and windows (LLIS) is one innovative approach recently proposed for Aedes control and under initial evaluation in different settings. Nevertheless, there is an urgent need to evaluate the efficacy of this intervention in endemic areas of dengue, where insecticide resistance in the mosquito populations has already developed after many years of selection pressure by the local vector control programmes. The aim of this PhD was to evaluate the efficacy of LLIS and assess the impact of insecticide resistance on this intervention. In 2012, cluster randomised controlled trials were conducted in two Mexican cities -Acapulco (Guerrero state) and Merida (Yucatan state). The study compared ten control and ten intervention areas of 100 households each across both cities. Intervention clusters included LLIS (Acapulco and Merida during the first year), followed by targeted treatment (TT) in the productive water container types (in Acapulco during the second year). Cross-sectional entomologic surveys quantified mosquito infestations at baseline (pre-intervention) and in four post-intervention samples surveys approximately at 6-monthly intervals corresponding to dry/rainy seasons. Sequentially over two years from 2012-2014, WHO cone bioassays were performed in order to determine the insecticidal activity of LLIS under operational conditions, susceptibility tests using CDC bottles, biochemical assays and genotyping for kdr were performed on F1 adult mosquitoes emerged from eggs collected using ovitraps. Overall, results showed significant reductions on adult vector densities in houses in the treated clusters with LLIS after two years at Merida and Acapulco: ca. 50% on the presence (OR≤0.62, P < 0.05) and abundance (IRR≤0.58, P < 0.05) of indoor-resting adults. In Acapulco, the combination of house screening with LLIS and TT of the most productive Ae. aegypti breeding sites had a significant impact on dengue vector populations and sustained that impact for up to 24 months. Based on the WHO efficacy criteria, the LLIS were efficient in killing susceptible Ae. aegypti (most of them achieving 80% of mortality) when first installed, but their activity rapidly declined. Much lower levels of mortality were achieved against the local and resistant Aedes population (less than 40%). The Ae. aegypti local populations demonstrated high levels of resistance to pyrethroids, mainly permethrin, some signs of decreased susceptibility for organophosphates but susceptibility to carbamates. Biochemical analysis showed a significant elevation of oxidases and GST enzyme activity and kdr-1016I and -1534C mutations were found at high frequencies in the two study sites. There was no clear effect attributable to the instalment of LLIS on the mechanism of insecticide resistance (kdr frequencies and levels of enzyme activity), but in terms of intensity of resistance, resistance seemed to be higher within the study arms with LLIS after the intervention. Although the efficacy of LLIS can be compromised by the degradation of the insecticide and/or the resistance of Aedes populations to pyrethroid-based insecticides, the physical barrier would still work as a preventive measure, as demonstrated in this study. The positive entomological impact observed in this study provides evidence of a sustained effect of LLIS on Ae. aegypti, and encourages the development of cluster randomised trials evaluating the epidemiological impact of this intervention.