Academic literature on the topic 'Vector control Biological control Philippines'
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Journal articles on the topic "Vector control Biological control Philippines"
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Christodoulou, Mario. "Biological vector control of mosquito-borne diseases." Lancet Infectious Diseases 11, no. 2 (February 2011): 84–85. http://dx.doi.org/10.1016/s1473-3099(11)70017-2.
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Kamareddine, Layla. "The Biological Control of the Malaria Vector." Toxins 4, no. 9 (September 19, 2012): 748–67. http://dx.doi.org/10.3390/toxins4090748.
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Lacey, Lawrence A., and Brucke K. Orr. "The Role of Biological Control of Mosquitoes in Integrated Vector Control." American Journal of Tropical Medicine and Hygiene 50, no. 6_Suppl (January 1, 1994): 97–115. http://dx.doi.org/10.4269/ajtmh.1994.50.97.
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Espino, Fe, Jesusa Marco, Nelia P. Salazar, Ferdinand Salazar, Ysadora Mendoza, and Aldwin Velazco. "Community-based dengue vector control: experiences in behavior change in Metropolitan Manila, Philippines." Pathogens and Global Health 106, no. 8 (December 2012): 455–60. http://dx.doi.org/10.1179/2047773212y.0000000061.
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Hareem Sajjad and Neelam Arif. "Biological Control of Mosquito Vectors." Scientific Inquiry and Review 3, no. 1 (January 31, 2019): 25–32. http://dx.doi.org/10.32350/sir.31.03.
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The main purpose of this review paper is to study different biological control methods for controlling mosquito vectors. Mosquitoes act as vector for many harmful diseases including malaria, dengue fever, yellow fever, filarial, encephalitis, chikungunya, dengue and poly arthritis. The use of chemical insecticides for controlling mosquitoes is limited because they develop resistance against these insecticides. So, efforts have been made to control the mosquito vectors by eco-friendly techniques. At present, biocontrol agents are used to control the mosquito species with the aim to reduce the impact and cost of insecticide based strategies. These biocontrol agents involve the use of natural enemies including bacteria, fungi, larvivorous fish, protozoans and nematodes. These agents target mosquitoes at different stages of their life cycle. In this paper, we focus on several bio-controlling methods used to reduce the population of mosquito vectors.
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Doloi, Dipika. "A study on certain biological control methods to control and manage vector-borne diseases." International Journal of Mosquito Research 8, no. 1 (January 1, 2021): 31–34. http://dx.doi.org/10.22271/23487941.2021.v8.i1a.497.
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Mishra, Prabhakar, Brij Kishore Tyagi, Natarajan Chandrasekaran, and Amitava Mukherjee. "Biological nanopesticides: a greener approach towards the mosquito vector control." Environmental Science and Pollution Research 25, no. 11 (July 18, 2017): 10151–63. http://dx.doi.org/10.1007/s11356-017-9640-y.
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Arias-Castro, Juddy Heliana, Hector Jairo Martinez-Romero, and Olga Vasilieva. "Biological and Chemical Control of Mosquito Population by Optimal Control Approach." Games 11, no. 4 (December 14, 2020): 62. http://dx.doi.org/10.3390/g11040062.
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This paper focuses on the design and analysis of short-term control intervention measures seeking to suppress local populations of Aedes aegypti mosquitoes, the major transmitters of dengue and other vector-borne infections. Besides traditional measures involving the spraying of larvicides and/or insecticides, we include biological control based on the deliberate introduction of predacious species feeding on the aquatic stages of mosquitoes. From the methodological standpoint, our study relies on application of the optimal control modeling framework in combination with the cost-effectiveness analysis. This approach not only enables the design of optimal strategies for external control intervention but also allows for assessment of their performance in terms of the cost-benefit relationship. By examining numerous scenarios derived from combinations of chemical and biological control measures, we try to find out whether the presence of predacious species at the mosquito breeding sites may (partially) replace the common practices of larvicide/insecticide spraying and thus reduce their negative impact on non-target organisms. As a result, we identify two strategies exhibiting the best metrics of cost-effectiveness and provide some useful insights for their possible implementation in practical settings.
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Pandey, Ritesh, R. N. Singh, and P. N. Pandey. "Mathematical Model for Malaria Transmission and Biological Control." Journal of the Tensor Society 8, no. 01 (June 30, 2009): 159–73. http://dx.doi.org/10.56424/jts.v8i01.10549.
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In this paper, a nonlinear mathematical model for the control of vector borne diseases, like malaria is proposed and analyzed. In the modeling process it is assumed that the mosquito population is controlled by using larvivorous fish, which partially depends on the larva of mosquito population. It is further assumed that the mosquito population grows logistically. The equilibria of the model are obtained and their stability is discussed by using stability theory of differential equations. Further numerical simulation is performed to verify the analytically obtained results.
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Chen-Charpentier, Benito. "Stochastic Modeling of Plant Virus Propagation with Biological Control." Mathematics 9, no. 5 (February 24, 2021): 456. http://dx.doi.org/10.3390/math9050456.
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Plants are vital for man and many species. They are sources of food, medicine, fiber for clothes and materials for shelter. They are a fundamental part of a healthy environment. However, plants are subject to virus diseases. In plants most of the virus propagation is done by a vector. The traditional way of controlling the insects is to use insecticides that have a negative effect on the environment. A more environmentally friendly way to control the insects is to use predators that will prey on the vector, such as birds or bats. In this paper we modify a plant-virus propagation model with delays. The model is written using delay differential equations. However, it can also be expressed in terms of biochemical reactions, which is more realistic for small populations. Since there are always variations in the populations, errors in the measured values and uncertainties, we use two methods to introduce randomness: stochastic differential equations and the Gillespie algorithm. We present numerical simulations. The Gillespie method produces good results for plant-virus population models.
Dissertations / Theses on the topic "Vector control Biological control Philippines"
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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.
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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
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Lees, Rosemary. "Developing transgenic Aedes aegypti for a release of insects with a dominant lethal (RIDL) programme." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670048.
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Yamoah, Emmanuel. "A model system using insects to vector Fusarium tumidum for biological control of gorse (Ulex europaeus)." Phd thesis, Lincoln University. Bio-Protection and Ecology Division, 2007. http://theses.lincoln.ac.nz/public/adt-NZLIU20080131.114607/.
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The overall objective of this study was to test the hypothesis that insects can vector F.
tumidum conidia to infect gorse plants with the aim of developing an alternative approach to mycoherbicide delivery to control weeds. Four potential insect species (Apion ulicis, Cydia ulicetana, Epiphyas postvittana and Sericothrips staphylinus) were assessed for their ability to vector F. tumidum conidia. To achieve this, the external microflora (bacteria and fungi) and the size and location of fungal spores on the cuticle of these insect species were determined. In addition, the ability of the insects to pick up and deposit F. tumidum conidia on agar was studied. Based on the results from these
experiments, E. postvittana was selected for more detailed experiments to determine transmission of F. tumidum to infect potted gorse plants. The factors promoting pathogenicity of F. tumidum against gorse and the pathogen loading required to infect and kill the weed were also determined.
The external microflora of the four insect species were recovered by washing and plating
techniques and identified by morphology and polymerase chain reaction restriction
fragment length polymorphism (PCR-RFLP) and sequencing of internally transcribed
spacer (ITS) and 16S rDNA. A culture-independent technique (direct PCR) was also used
to assess fungal diversity by direct amplification of ITS sequences from the washings of the insects. All insect species carried Alternaria, Cladosporium, Nectria, Penicillium,
Phoma, Pseudozyma spp. and entomopathogens. Ninety four per cent of the 178 cloned
amplicons had ITS sequences similarity to Nectria mauritiicola. E. postvittana carried the
largest fungal spores (mean surface area of 125.9 ìm2) and the most fungal CFU/insect.
About 70% of the fungi isolated from the insects were also present on the host plant
(gorse) and the understorey grass. The mean size of fungal spores recovered from the
insect species correlated strongly with their body length (R² = 85%). Methylobacterium
aquaticum and Pseudomonas lutea were common on all four insect species.
Pseudomonas fluorescens was the most abundant bacterial species.
In the pathogenicity trials, the effectiveness of F. tumidum in reducing root and shoot
biomass of 16 and 8 wk old gorse plants was significantly increased with wounding of the
plants. Older plants (32 wk old) which were wounded and inoculated were significantly
shorter, more infected and developed more tip dieback (80%) than plants which were not
wounded (32%). This indicates that damage caused by phytophagous insect species
present on gorse through feeding and oviposition may enhance infection by F. tumidum.
Wounding may release nutrients (e.g. Mg and Zn) essential for conidia germination and
germ tube elongation and also provide easier access for germ tube penetration. Conidial
germination and germ tube length were increased by 50 and 877%, respectively when
incubated in 0.2% of gorse extract solution for 24 h compared with incubation in water.
Inoculum suspensions amended with 0.2% of gorse extract caused more infection and
significantly reduced biomass production of 24 wk old gorse plants than suspensions
without gorse extract. A minimum number of about 900 viable conidia/infection site of F.
tumidum were required to infect gorse leaves. However, incorporation of amendments
(which can injure the leaf cuticle) or provision of nutrients (i.e. gorse extract or glucose)
in the formulation might decrease the number of conidia required for lesion formation.
Scanning electron micrographs showed that germ tube penetration of gorse tissue was
limited to open stomata which partly explain the large number of conidia required for
infection. The flowers and leaves were more susceptible to F. tumidum infection than the
spines, stems and pods. An experiment to determine the number of infection sites
required to cause plant mortality showed that the entire plant needs to be inoculated in
order for the pathogen to kill 10 wk old plants as F. tumidum is a non systemic pathogen.
The number of infection sites correlated strongly with disease severity (R² = 99.3%). At
least 50% of the plant was required to be inoculated to cause a significant reduction in
shoot dry weight. F. tumidum, applied as soil inoculant using inoculated wheat grains in three separate experiments, significantly suppressed gorse seedling emergence and biomass production.
In experiments to determine the loading capacity of the insect species, E. postvittana, the
largest insect species studied, carried significantly more (68) and deposited significantly more (29) F. tumidum conidia than the other species. Each E. postvittana, loaded with 5,000 conidia of F. tumidum, transmitted approximately 310 conidia onto gorse plants but
this did not cause any infection or affect plant growth as determined by shoot fresh
weight and shoot height. E. postvittana on its own did not cause any significant damage
to gorse and did not enhance F. tumidum infection. It also failed to spread the pathogen
from infected plants to the healthy ones. There was no evidence of synergism between the
two agents and damage caused by the combination of both E. postvittana and F. tumidum
was equivalent to that caused by F. tumidum alone.
This study has shown that E. postvittana has the greatest capacity to vector F. tumidum
since it naturally carried the largest and the most fungal spores (429 CFU/insect).
Moreover, it naturally carried Fusarium spp. such as F. lateritium, F. tricinctum and
Gibberella pulicaris (anamorph Fusarium sambucinum) and was capable of carrying and
depositing most F. tumidum conidia on agar. Coupled with the availability of pheromone
for attracting the male insects, E. postvittana may be a suitable insect vector for
delivering F. tumidum conidia on gorse using this novel biocontrol strategy. Although it
is a polyphagous insect, and may visit non-target plants, F. tumidum is a very specific
pathogen of gorse, broom and a few closely related plant species. Hence, using this insect
species to vector F. tumidum in a biological control programme, should not pose a
significant threat to plants of economic importance. However, successful control of gorse
using this "lure-load-infect" concept would depend, to a large extent on the virulence of
the pathogen as insects, due to the large size of F. tumidum macroconidia, can carry only
a small number of it.
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Lobo, Katiane dos Santos. "Isolamento, caracterização molecular e avaliação da toxicidade de Bacillus thuringiensis Berliner, 1911 do Cerrado Maranhense em larvas de Aedes aegypti (Linnaeus, 1762) (Diptera, Culicidae)." Universidade Federal do Maranhão, 2015. http://tedebc.ufma.br:8080/jspui/handle/tede/1023.
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Previous issue date: 2015-04-30FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTIFICO E TECNOLÓGICO DO MARANHÃO
Currently dengue is a serious global public health problem, in Brazil there is increase in the number of cases every year and the circulation of several serotypes. The development of new strategies for the control of Aedes aegypti is of utmost importance to minimize or eliminate the cases of the disease. An alternative for the control of this vector is the use of biological control agents such as Bacillus thuringiensis, which is toxic to this insect order of epidemiological importance. In this study, we sought to investigate the biological control of A. aegypti, with the use of B. thuringiensis isolated from Cerrado Maranhense. Selective bioassays were conducted to determine the entomopathogenic activity against the larvae of A. aegypti, quantitative bioassays in order to determine the toxicity of isolates, by means of the estimation of Median Lethal Concentration (LC50) and PCR tests (Polymerase Chain Reaction) to verify the presence of mosquitocidal genes (cry and cyt). From 45 soil samples collected in 17 counties in the State, it was obtained 1225 bacterial colonies, with 383 (31.26%) identified as B. thuringiensis. Of the 383 isolates tested, 12 (3.13%) showed larvicidal activity greater than 50% (BtMA 25, BtMA 64, BtMA 104, BtMA 131, BtMA 194, BtMA 251, BtMA 401, BtMA 410, BtMA 413, BtMA 450, BtMA 451 and BtMA 560), which were selected for subsequent realization of the quantitative bioassay and molecular characterization. The quantitative bioassays allowed to observe that the lower LC50 values were obtained with the isolate 401 (4.0 x 104 spore-crystals/mL) and with the standard bacteria Bti (0.32 x 107 spore-crystals/mL). The others tested isolates showed low larvicidal activity. The PCR analysis showed that from eight tested genes: cry4Aa, cry4Ba, cry10Aa, cry11Aa, cry11Ba, cyt1Aa, cyt1Ab and cyt2Aa, five of them: cry11Aa, cry11Ba, cyt1Aa, cyt1Ab and cyt2Aa were detected in ten isolates, being absent in only two of 12 isolates tested. These data demonstrate that the isolates of B. thuringiensis from Cerrado Maranhense showed high pathogenicity and potential for biological control of A. aegypti.
Atualmente a dengue é um grave problema de saúde pública mundial, no Brasil verifica-se aumento do número de casos a cada ano e a circulação de vários sorotipos virais. O desenvolvimento de novas estratégias para o controle do Aedes aegypti é de extrema importância, para minimizar ou erradicar os casos da doença. Uma alternativa para o controle deste vetor é a utilização de agentes de controle biológico, como Bacillus thuringiensis, que apresenta toxicidade a essa ordem de inseto de importância epidemiológica. Neste estudo, buscou-se investigar o controle biológico de A. aegypti, com o uso de B. thuringiensis isolados do Cerrado Maranhense. Foram realizados bioensaios seletivos para determinar a atividade entomopatogênica contra as larvas de A. aegypti, bioensaios quantitativos com a finalidade de determinar a toxicidade dos isolados, por meio da estimativa da Concentração Letal Mediana (CL50) e testes de PCR (Reação em Cadeia da Polimerase) para verificar a presença de genes mosquitocida (cry e cyt). A partir de 45 amostras de solo coletadas em 17 municípios do estado, obteve-se 1225 colônias bacterianas, sendo 383 (31,26%) identificadas como B. thuringiensis. Dos 383 isolados testados, 12 (3,13%) mostraram atividade larvicida superior a 50% (BtMA 25, BtMA 64, BtMA 104, BtMA 131, BtMA 194, BtMA 251, BtMA 401, BtMA 410, BtMA 413, BtMA 450, BtMA 451 e BtMA 560), aos quais foram selecionados para posterior realização do bioensaio quantitativo e caracterização molecular. Os bioensaios quantitativos permitiram observar que os menores valores de CL50 foram obtidos com o isolado 401 (4,0 x 104 esporos-cristais/mL) e com a bactéria padrão Bti (0,32 x 107 esporos-cristais/mL). Os demais isolados testados mostraram baixa atividade larvicida. Os testes de PCR mostraram que dos oito genes testados: cry4Aa, cry4Ba, cry10Aa, cry11Aa, cry11Ba, cyt1Aa, cyt1Ab e cyt2Aa, cinco destes: cry11Aa, cry11Ba, cyt1Aa, cyt1Ab e cyt2Aa foram detectados em dez isolados, estando ausentes em apenas dois dos 12 isolados testados. Esses dados demonstram que os isolados de B. thuringiensis do Cerrado Maranhense apresentaram alta patogenicidade e potencial para o controle biológico de A. aegypti.
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Rugno, Gabriel Rodrigo. "Seletividade de inseticidas utilizados na cultura dos citros ao predador Ceraeochrysa cubana (Hagen, 1861) (Neuroptera: Chrysopidae), desenvolvimento em diferentes temperaturas e diversidade de crisopídeos em propriedades com manejo intensivo e convencional de Diaphorina citri Kuwayama (Hemiptera: Liviidae)." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11146/tde-23042013-112046/.
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O crisopídeo Ceraeochrysa cubana (Hagen, 1861) é um importante predador na cultura dos citros. Apesar da grande importância de C. cubana, pouco se conhece sobre a biologia e o efeito dos inseticidas a este crisopídeo, o que seria fundamental para um programa de Manejo Integrado de Pragas. Com essa pesquisa objetivou-se avaliar o efeito: a) letal e subletal de inseticidas aplicados sobre ovos com 3 idades diferentes; b) letal e subletal de inseticidas sobre larvas de primeiro instar; c) letal e subletal de inseticidas aplicados sobre pupas e adultos; d) do manejo de Diaphorina citri Kuwayama (Hemiptera: Liviidae) na população de crisopídeos; e) de seis temperaturas sobre a biologia de C. cubana. Verificou-se que não houve diferença significativa das variáveis avaliadas entre os tratamentos, dentre os ovos com 24, 72 e 120 horas. O produto Lorsban® 480 BR afetou a viabilidade dos ovos das três idades e foi o inseticida que mais afetou o predador quando aplicado sobre os ovos, classificado como moderadamente nocivo (classe 3). Em larvas, os inseticidas Lorsban® 480 BR e Malathion® 1000 EC tiveram efeito letal, causando 100% de mortalidade 24h após a aplicação e os inseticidas Azamax® e Engeo Pleno® foram os únicos produtos que tiveram efeito subletal sobre as pupas oriundas das larvas tratadas e nenhum dos produtos testados foram classificados como inócuos (classe 1) ao predador. Nenhum dos inseticidas testados teve efeito letal e subletal quando aplicados sobre as pupas, sendo classificados como inócuos, já, quando aplicados sobre adultos, os inseticidas Actara® 250 WG, Ampligo®, Engeo Pleno®, Lorsban® 480 BR e Malathion® 1000 EC causaram 100% de mortalidade e todos os produtos testados sobre os adultos foram nocivos, exceto Evidence® 700 WG, Imidan® 500 WP e Tiger® 100 EC, que foram classificados como moderadamente nocivos. Nas coletas de crisopídeos feitas em campo, a espécie Ceraeochrysa cincta (SCHNEIDER, 1851) foi a mais coletada, observou-se também que na propriedade com manejo menos intensivo de D. citri foi coletado um número maior de indivíduos comparado com a propriedade com manejo rigoroso. Em relação à biologia, verificou-se um aumento na velocidade do desenvolvimento das fases do predador em função da temperatura e a viabilidade da fase de ovo e larva não foi afetada, porém, a temperatura de 18°C afetou a viabilidade da pupa e no ciclo ovoadulto, além dessa temperatura, a de 32°C também afetou a viabilidade. Para o ciclo total de C. cubana foram necessários 354,61 GD e a temperatura base (Tb) foi de 12,72°C.The lacewing Ceraeochrysa cubana (Hagen, 1861) is an important predator of citrus pests. Still, little is known about the biology and the effect of insecticides on this green lacewing, which is essential for an Integrated Pest Management program. The aim of this study was to evaluate: a) lethal and sublethal effects of insecticides applied on eggs at 3 different ages, b) lethal and sublethal effects of insecticides on the first larval instar c) lethal and sublethal effects of insecticides applied to pupae and adults; d) effects of the management of Diaphorina citri Kuwayama (Hemiptera: Liviidae) in a lacewing population e) effects of six temperatures on the C. cubana biology. We found no significant differences for the variables in the treatments for eggs at 24, 72 and 120 hours. The insecticide Lorsban® 480 BR affected the viability of the eggs at the three ages and most affected the predator when applied on the eggs, classified as moderately harmful (class 3). On the larvae, the insecticides Lorsban® 480 BR and Malathion® 1000 EC had lethal effect, occurring 100% mortality of the larvae 24h after application of insecticides, and Azamax® and Engeo Pleno® were the only products that presented sublethal effects on pupae from treated larvae and none of the products tested were classified as harmless (class 1) to the predator. None of the insecticides tested had lethal and sublethal effect when applied on the pupae, and were classified as harmless. When applied to adults, insecticides Actara® 250 WG, Ampligo®, Engeo Pleno®, Lorsban® 480 BR and Malathion® 1000 EC caused 100% of mortality of the adult predator and all products tested on adults were harmful, except for Evidence® 700 WG, Imidan® 500 WP and Tiger® 100 EC, which were classified as moderately harmful. In the collections of green lacewings in the field, the species Ceraeochrysa cincta was predominant. We also observed that in orchards under less intensive management of D. citri, a larger number of individuals were collected compared to the orchards under a strict management system. Regarding biology, we observed an increase in growth speed in instars of the predator due to temperature, but the viability of eggs and larvae were not affected. However, the temperature of 18°C affected the pupae viability and the eggadult cycle. The temperature of 32°C also affected viability. For total cycle of C. cubana took 354.61 degrees day (DD) and thermal threshold (Tb) was 12.72°C.
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Nersesov, Sergey G. "Nonlinear Impulsive and Hybrid Dynamical Systems." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7147.
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Modern complex dynamical systems typically possess a
multiechelon hierarchical hybrid structure characterized by
continuous-time dynamics at the lower-level units and logical
decision-making units at the higher-level of hierarchy. Hybrid
dynamical systems involve an interacting countable collection of
dynamical systems defined on subregions of the partitioned state
space. Thus, in addition to traditional control systems, hybrid
control systems involve supervising controllers which serve to
coordinate the (sometimes competing) actions of the lower-level
controllers. A subclass of hybrid dynamical systems are impulsive
dynamical systems which consist of three elements, namely, a
continuous-time differential equation, a difference equation, and
a criterion for determining when the states of the system are to
be reset. One of the main topics of this dissertation is the
development of stability analysis and control design for impulsive
dynamical systems. Specifically, we generalize Poincare's
theorem to dynamical systems possessing left-continuous flows to
address the stability of limit cycles and periodic orbits of
left-continuous, hybrid, and impulsive dynamical systems. For
nonlinear impulsive dynamical systems, we present partial
stability results, that is, stability with respect to part of the
system's state. Furthermore, we develop adaptive control framework
for general class of impulsive systems as well as energy-based
control framework for hybrid port-controlled Hamiltonian systems.
Extensions of stability theory for impulsive dynamical systems
with respect to the nonnegative orthant of the state space are
also addressed in this dissertation. Furthermore, we design
optimal output feedback controllers for set-point regulation of
linear nonnegative dynamical systems. Another main topic that has
been addressed in this research is the stability analysis of
large-scale dynamical systems. Specifically, we extend the theory
of vector Lyapunov functions by constructing a generalized
comparison system whose vector field can be a function of the
comparison system states as well as the nonlinear dynamical system
states. Furthermore, we present a generalized convergence result
which, in the case of a scalar comparison system, specializes to
the classical Krasovskii-LaSalle invariant set theorem. Moreover,
we develop vector dissipativity theory for large-scale dynamical
systems based on vector storage functions and vector supply rates.
Finally, using a large-scale dynamical systems perspective, we
develop a system-theoretic foundation for thermodynamics.
Specifically, using compartmental dynamical system energy flow
models, we place the universal energy conservation, energy
equipartition, temperature equipartition, and entropy
nonconservation laws of thermodynamics on a system-theoretic
basis.
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Rossi-Zalaf, Luciana Savoi. "Controle microbiano de Brevipalpus phoenicis (Geijskes, 1939) com Hirsutella thompsonii Fisher." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/11/11146/tde-10052007-151758/.
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Avaliou-se o efeito de Hirsutella thompsonii ao ácaro da leprose dos citros (Brevipalpus phoenicis). Em laboratório, adultos foram mantidos em arenas sobre folhas de citros em placas contendo ágar-água solidificado. Foram avaliadas a patogenicidade e virulência do fungo ao ácaro, bem como sua persistência e compatibilidade com acaricidas. No campo, os ácaros foram confinados em arenas sobre frutos de laranja pré-infestados com adultos, sendo estes mantidos em plantas de citros. O isolado Esalq-1269 de H. thompsonii foi inoculado em populações do ácaro provenientes de diversas regiões do Estado de São Paulo. Para se verificar o efeito combinado da temperatura e umidade relativa do ar, o patógeno foi aplicado e os ácaros mantidos em condições controladas. A eficiência de Esalq-1269 foi comparada com isolados do banco de patógenos do Cenargen/Embrapa, os quais foram identificados. Além destes testes, determinou-se o efeito de Esalq-1269 em ovos de B. phoenicis. As avaliações da virulência e persistência foram realizadas a partir do patógeno produzido em meio de cultura completo e sólido (MC-S); meio completo e líquido (MC-L); arroz pré-cozido (APC) e arroz pré-cozido seco e moído (APC-SM). Nos bioensaios com os acaricidas, determinou-se a compatibilidade com agrotóxicos registrados para B. phoenicis phoenicis em citros. O efeito de sub-concentrações de H. thompsonii e de Propargite (Omite 720 SC) foram avaliadas, isoladamente e em mistura, para o ácaro. Em todos os bioensaios, as suspensões contendo propágulos do fungo foram preparadas em diferentes concentrações e após a pulverização avaliou-se a mortalidade durante quatro dias. No experimento de campo o patógeno foi aplicado em diferentes concentrações. O primeiro experimento constou da testemunha e H. thompsonii produzida em APC (6kg/ha). O segundo experimento constou: testemunha, H. thompsonii produzida em APC (20kg/ha e 10kg/ha) e H. thompsonii produzida em MC-L (5L/ha). As avaliações foram realizadas após 10 e 20 dias das aplicações, verificando a sobrevivência de adultos e o número de ovos e ninfas. Esalq-1269 foi patogênico a adultos de B. phoenicis provenientes de todas as regiões do Estado avaliadas, porém com diferenças quanto suscetibilidade. Todos os isolados testados foram patogênicos a B. phoenicis, sendo Esalq-1269 o mais virulento. Nos testes de temperatura x umidade, observou-se que Esalq-1269 apresentou alta atividade a 30°C, independentemente da umidade relativa. Porém, baixas temperaturas prejudicaram o desenvolvimento da doença. O patógeno não apresentou efeito em ovos do ácaro. Nos testes de virulência, a menor CL25 obtida foi para o fungo produzido em MC-S (1,9x105con/mL), já as CL25 para o patógeno produzido em APC e APCSM foram semelhantes. O fungo produzido em MC-L foi o que apresentou maior persistência em relação aos demais, sendo capaz de causar mortalidade devido ao efeito indireto. Quanto à toxicidade, a exceção de Dicofol e Cihexatina, todos os acaricidas foram compatíveis com o fungo. Observou-se efeito sinérgico entre a mistura patógeno x propargite, com alta mortalidade de B. phoenicis em sub-concentrações. Em campo, houve diferenças dos tratamentos com o fungo em relação à testemunha, havendo redução no número de adultos e de ovos.This study aimed to evaluate the effect of Hirsutella thompsonii on the false spider mite (Brevipalpus phoenicis). In laboratory bioassays, adults were confined to arenas prepared with citrus leaves in acrylic dishes containing water-agar. The pathogenicity and virulence of the fungus against B. phoenicis adults, the persistence in citrus leaves and the compatibility with acaricides were studied. Adults were maintained in arenas prepared with fruits which were placed in plants in the field. The H. thompsonii isolate Esalq-1269 was inoculated on mite populations from different regions of São Paulo state. Also, the combined effect of temperature and humidity was measured on the fungus performance when mites were maintained in controlled conditions. The efficiency of Esalq-1269 was compared to isolates from Embrapa Recursos Genéticos e Biotecnologia. Besides these bioassays, the effect of Esalq-1269 isolate in eggs of B. phoenicis was determined. The virulence and persistence tests were conducted using the fungi produced on complete solid culture medium (MC-S); complete liquid culture medium (MC-L); rice (APC) and rice powder (APC-SM). Compatibility of acaricides registered for B. phoenicis control with Esalq-1269 was evaluated and the combined effect of Propagite (Omite 720 SC) with sub-doses of H. thompsonii was determined. Mortality of mites was observed during four days after application of conidial suspensions. In field tests, the pathogen was applied in different concentrations. In the first assay, fungi were produced in APC (6kg/ha). In the second test, three treatments were applied: H. thompsonii cultured on rice (APC) at two concentrations (20Kg/ha and 10 Kg/ha) and H. thompsonii produced by liquid fermentation (MC-L) (5L/ha). Observations were performed after 10 and 20 days after application and adult survival, number of eggs and nymphs per fruit were observed. The isolate Esalq-1269 caused high mortality in all populations of B. phoenicis tested. Also, this strain was the most virulent against the mite and it was negatively affected by low temperatures. At 30°C, high mortality of adults was observed regardless of humidity levels. B. phoenicis was not pathogenic to eggs of B. phoencis . The lowest LC25 value calculated was from pathogen produced in MC-S (1,9x105 conidia/mL). The LC25 values calculated to APC and ACP-SM did not differ statistically. The pathogen produced by liquid fermentation was the most persistent in citrus leaves, causing higher levels of adult mortality. The acaricides Dicofol and Cyhexatin were toxic to Esalq-1269. Synergism between Propargite and H. thompsonii was observed resulting in high adult mortality under low concentrations. In field, results showed differences on concentration and time to death between treatments and control. Field applications resulted in reduction of adult and eggs.
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Ravallec, Marc. "Recherches sur le potentiel larvicide d'hyphomycetes entomopathogenes a l'egard des dipteres aedes albopictus skuse 1891 et toxorhynchites amboinensis doleschall 1857." Paris 6, 1987. http://www.theses.fr/1987PA066080.
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A l'aide d'essais de contamination menes dans les conditions controlees du laboraoire, le potentiel larvicide des hyphomycetes metarhizium anisopliae et tolypocladium cylindrosporum est eprouve sur le moustique aedes albopictus, un important vecteur de la dengue. Le role de l'age larvaire et de la mue comme facteurs de resistance aux infections est discute. Le spectre d'hote de la souche ma 139 est etudie sur les larves culiciphages du moustique toxorhyncites amboinensis. Des larves proies prealablement infectees par cette souche representent un inoculum potentiel pour ce predateur. Le mode d'action de ces germes est approfondi par des etudes histologiques et ultrastructurales qui ont notamment permis de suivre le comportement de leurs spores dans le mesenteron des larves et la penetration cuticulaire de t. Cylindrosporum. Le determinisme des processus toxemiques impliques dans la pathogenie de m. Anisopliae est precise par l'evaluation du nombre de spores ingerees par les larves
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Charles, Jean-François. "Bacillus thuringiensis sérotype H 14 et bacillus sphaericus : sporulation, biogenèse des cristaux larvicides et cytopathologie sur larves de moustiques (diptères; culicidae)." Paris 6, 1987. http://www.theses.fr/1987PA066303.
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Yamoah, E. "A model system using insects to vector Fusarium tumidum for biological control of gorse (Ulex europaeus) : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Lincoln University /." Diss., 2007. http://hdl.handle.net/10182/299.
Full textBooks on the topic "Vector control Biological control Philippines"
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W, Service M., ed. Pest and vector control. Cambridge: Cambridge University Press, 2004.
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Jayaraman, Kunthala. Biotechnological approaches to vector control health-care programme. [New Delhi]: Rajiv Gandhi Institute for Contemporary Studies, 1995.
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Martin, Franz Jost, ed. Biological plant and health protection.: International Symposium of the Akademie der Wissenschaften und der Literatur, Mainz, November 15th-17th, 1984, at Mainz and Darmstadt. Stuttgart: G. Fischer, 1986.
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de, Barjac Huguette, ed. Biological control of vectors: Manual for collecting, field determination, and handling of biofactors for control of vectors. Chichester [England]: Published on behalf of the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR) by J. Wiley, 1991.
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Serap, Aksoy, ed. Transgenesis and the management of vector-borne disease. New York: Springer Science+Business Media, 2008.
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Symposium on Biotechnological and Environmental Approaches to Forest Pest and Disease Management (1993 Quezon City, Philippines). Proceedings of the Symposium on Biotechnological and Environmental Approaches to Forest Pest and Disease Management, Quezon City, Philippines, 28-30 April 1993. Edited by Halos S. C and Regional Center for Tropical Biology (Bogor, Indonesia). Bogor, Indonesia: Southeast Asian Regional Centre for Tropical Biology, 1994.
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Shields, Vonnie D. C., ed. Biological Control of Pest and Vector Insects. InTech, 2017. http://dx.doi.org/10.5772/63274.
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Service, M. W., and H. F. van Emden. Pest and Vector Control. Cambridge University Press, 2004.
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Service, M. W., and H. F. van Emden. Pest and Vector Control. Cambridge University Press, 2006.
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Emden, H. F. Van, and M. W. Service. Pest and Vector Control. Cambridge University Press, 2004.
Find full textBook chapters on the topic "Vector control Biological control Philippines"
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Machtinger, Erika T., and Christopher J. Geden. "11. Biological control with parasitoids." In Ecology and Control of Vector-borne Diseases, 299–335. The Netherlands: Wageningen Academic Publishers, 2018. http://dx.doi.org/10.3920/978-90-8686-863-6_11.
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Rahamathulla, Mohamudha Parveen. "Biological Control of Aquatic Snail-Borne Diseases (Schistosomiasis)." In Microbial Control of Vector-Borne Diseases, 373–418. Boca Raton : Taylor & Francis, 2018.: CRC Press, 2018. http://dx.doi.org/10.1201/b22203-19.
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Weeks, Emma N. I., Erika T. Machtinger, Diana Leemon, and Christopher J. Geden. "12. Biological control of livestock pests: entomopathogens." In Ecology and Control of Vector-borne Diseases, 337–87. The Netherlands: Wageningen Academic Publishers, 2018. http://dx.doi.org/10.3920/978-90-8686-863-6_12.
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Mohanty, Ipsita, Animesha Rath, and Rupenangshu Kumar Hazra. "Wolbachia: Biological Control Strategy Against Arboviral Diseases." In Genetically Modified and other Innovative Vector Control Technologies, 215–45. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-2964-8_11.
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Moreira, Luciano A. "Wolbachia in Aedes mosquitoes: towards biological control of vector-borne diseases." In Ecology of parasite-vector interactions, 155–65. Wageningen: Wageningen Academic Publishers, 2013. http://dx.doi.org/10.3920/978-90-8686-744-8_8.
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Klingen, Ingeborg, and Gilian van Duijvendijk. "20. Biological control of the tick Ixodes ricinus by pathogens and invertebrates." In Ecology and Control of Vector-borne Diseases, 279–93. The Netherlands: Wageningen Academic Publishers, 2016. http://dx.doi.org/10.3920/978-90-8686-838-4_20.
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Reddya Naik, B. "Biological Control of Culex quinquefasciatus Say, 1823 (Diptera: Culicidae), the Ubiquitous Vector for Lymphatic Filariasis: A Review." In Lymphatic Filariasis, 281–92. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-1391-2_22.
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Moya-Raygoza, Gustavo. "Biological Control of the Leafhopper Dalbulus maidis in Corn Throughout the Americas: Interaction Among Phytoplasma- Insect Vector- Parasitoids." In Sustainability in Plant and Crop Protection, 203–18. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-29650-6_9.
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Galil, Bella S. "A Sea, a Canal, a Disaster: The Suez Canal and the Transformation of the Mediterranean Biota." In Palgrave Studies in Maritime Politics and Security, 199–215. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-15670-0_10.
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AbstractThe introduction of non-native species is among the main direct drivers of biodiversity change. Off the Israeli coast 445 non-native species were recorded thus far, more than anywhere in the Mediterranean Sea. The number of recorded introductions has been rising inexorably, tripling since the 1970s. Nearly all have been introduced through the ever-enlarged Suez Canal. Worldwide there is no other vector of marine bioinvasions that delivers as high a propagule supply for so long to a certain locale. Once established, the non-native species are unlikely to be contained or controlled and their impacts are irreversible. The Canal-introduced species form prominent micro-communities and biological facies in most littoral habitats, some have been documented to displace or reduce populations of native species, alter community structure and food webs, change ecosystem functioning and the consequent provision of goods and services—profound ecological impacts that undermine the goals of sustainable blue economy in the Mediterranean Sea.These species have been spreading throughout the Mediterranean Sea while the Israeli shelf serves as a hotspot, beachhead, and dispersal hub. Their spatial and temporal spread has advanced concurrently with successive enlargements of the Suez Canal, rise in mean seawater temperature, and prevalence, duration, and severity of marine heat waves increase. The invasion poses a challenge to the environmental ethics and policies of the Mediterranean countries. As signatories to the Convention on Biological Diversity these countries are required to prevent the introduction of, control or eradicate alien species which threaten ecosystems, habitats or species (Article 8(h)), and ensure that the environmental consequences of their policies that are likely to have significant adverse effects on biological diversity are taken into account (Article 14.1). The present Egyptian government is in a position to reduce future introductions. Egypt announced the development of 35 desalination plants, of which the first 17 plants will add 2.8 million m3 daily capacity. It is suggested that an environmental impact assessment evaluates the environmental and economic consequences of utilizing the brine effluents from the large-scale desalination plants constructed in the vicinity of the Suez Canal to restore the salinity barrier once posed by the Bitter Lakes.
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"Biological control." In Pest and Vector Control, 147–76. Cambridge University Press, 2001. http://dx.doi.org/10.1017/cbo9780511616334.008.
Full textConference papers on the topic "Vector control Biological control Philippines"
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Flores, Mary Jane C. "Search for potential biological control agent of cattle fever tick in the Philippines." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.105445.
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Almarinez, Billy Joel Mondragon. "Biological control of invasive pest species in the Philippines: The case of coconut scale insect,Aspidiotus rigidus." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.94609.
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Mostoles, Maria Dulce J. "Biological control initiatives of the Central Bicol State University of Agriculture (CBSUA), Bicol region, Southern Luzon, Philippines." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.105446.
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Kuo, Huang-Cheng, Yu-Cheng Tseng, and Jen-Peng Huang. "Learning Weight Assignment in Distance Function for Biological Sequence Feature Vector by Genetic Algorithm." In Second International Conference on Innovative Computing, Informatio and Control (ICICIC 2007). IEEE, 2007. http://dx.doi.org/10.1109/icicic.2007.369.
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Hanna, Rachid. "Prospects of biological control and other management options of the banana aphidPentalonia nigronervose, the vector of banana bunchy top virus in Africa." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.115540.
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Lee, Chae J., Bernard D. Reger, Matthew C. Tresch, J. Edward Colgate, and Ferdinando A. Mussa-Ivaldi. "Emulation of Biological Motor Primitives in an Artificial System: The Generation of Static Force Fields." In ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0122.
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Abstract We have used observations of posture and movements in biological limbs to derive a controller for an artificial mechanism. The controller architecture emulates some of the known relations between spinal cord circuitry and the musculoskeletal system of vertebrates and, specifically, of the rat. This work relates to recent experiments suggesting that the neural circuitry of the spinal cord may be partitioned into a small set of functional modules. Activation of these modules, each connected to a set of limb muscles, resulted in force fields that have been measured at the endpoint of a limb. These force fields map each position of the foot into a corresponding static force vector. The force fields have been found to converge toward equilibrium positions located inside the leg’s workspace. The experimental observation that vector fields induced by multiple stimulations add vectorially, suggested that convergent force fields form a system of building blocks (or “primitives”) for the generation of stable postures and movements. To emulate this biological mechanism in the control of an artificial two-joint limb, we established relationships among three hierarchical levels — spinal modules, muscles, and actuators — by deriving the mappings among the respective output fields. These mappings are used in combination with an inverse model of the actuators to calculate the actuator commands that generate a desired force field. We tested the ability of this control system to reproduce the force fields generated by the leg muscles of the rat and a set of force fields with significant geometrical features. Our results show that we can successfully and reliably transfer to our artificial system the features of muscle force fields. In addition, we exploited the same principle of vector summation observed in the biological system to combine these muscle fields into a variety of force field patterns, including the gradients of Gaussian potentials and locally parallel fields. We consider this a first step in the generation of a biomorphic motor control system. This work is supported by ONR grant N00014-95-1-0571 and NIH grant MH48185.
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Sloboda, Andrew R., and Bogdan I. Epureanu. "Rotating Microsensors With Non-Linear Feedback." In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30751.
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The need for instruments that detect and quantify small amounts of chemical and biological agents has spurred the development of micro-scale and nano-scale resonators. Most of these sensors are variations of vibrating cantilever beams and rely on resonant frequency shifts to quantify added mass. While very sensitive in vacuum or low viscosity environments, these types of sensors suffer performance degradation in viscous fluids, where damping is significantly increased. This paper presents a unique sensor architecture consisting of an immersed micro-plate designed to vibrate rotationally about an axis as fluid flows past it in a micro-channel. The idea behind this design is that some of the energy in the incoming flow can be harvested due to fluid-structure interaction, thereby reducing the effective damping. Only a small outside energy input is then required to obtain sustained, large amplitude vibrations. We show how sensitivity vector techniques applied to such a device can provide an alternate means of effectively detecting small mass variations. A method of optimizing the feedback control in order to maximize sensitivity using a spline-based force surface spanning the state space is also presented.
Reports on the topic "Vector control Biological control Philippines"
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Hackett, Kevin, Shlomo Rottem, David L. Williamson, and Meir Klein. Spiroplasmas as Biological Control Agents of Insect Pests. United States Department of Agriculture, July 1995. http://dx.doi.org/10.32747/1995.7613017.bard.
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Toward development of spiroplasmas as novel toxin-delivery systems for biocontrol of beetle pests in the United States (Leptinotarsa decemlineata) and Israel (Maladera matrida), media for cultivating beetle-associated spiroplasmas were improved and surveys of these spiroplasmas were conducted to provide transformable strains. Extensive surveys of spiroplasmas yielded promising extrachromosomal elements for vector constructs. One, plasmid pCT-1, was cloned, characterized, and used as a source of spiroplasma origin of replication in our shuttle vectors. The fibrillin gene was isolated and sequenced and its strong promoter was also used in the constructs. Means for transforming these vectors into spiroplasmas were developed and optimized, with electroporation found to be suitable for most applications. Development and optimization of means for using large unilamellar vesicles (LUVs) in spiroplasma transformation represents a breakthrough that should facilitate insertion of large clusters of virulence genes. With completion of the vector, we should thus be poised to genetically engineer spiroplasmas with genes that will express toxins lethal to our target beetles, thus providing an effective and inexpensive alternative to conventional means of beetle control.
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Ullman, Diane, James Moyer, Benjamin Raccah, Abed Gera, Meir Klein, and Jacob Cohen. Tospoviruses Infecting Bulb Crops: Evolution, Diversity, Vector Specificity and Control. United States Department of Agriculture, September 2002. http://dx.doi.org/10.32747/2002.7695847.bard.
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Objectives. The overall goal of the proposed research was to develop a mechanistic understanding of tospovirus evolution, diversity and vector specificity that could be applied to development of novel methods for limiting virus establishment and spread. Our specific objectives were: 1) To characterize newly intercepted tospoviruses in onion, Hippeastrum and other bulb crops and compare them with the known tomato spotted wilt virus (TSWV) and its isolates; 2) To characterize intra- and interspecific variation in the virus transmission by thrips of the new and distinct tospoviruses. and, 3) To determine the basis of vector specificity using biological, cellular and molecular approaches. Background. New tospoviruses infecting bulb crops were detected in Israel and the US in the mid-90s. Their plant host ranges and relationships with thrips vectors showed they differed from the type member of the Tospovirus genus, tomato spotted wilt virus (TSWV). Outbreaks of these new viruses caused serious crop losses in both countries, and in agricultural and ornamental crops elsewhere. In the realm of plant infecting viruses, the tospoviruses (genus: Tospovirus , family: Bunyaviridae ) are among the most aggressive emerging viruses. Tospoviruses are transmitted by several species of thrips in a persistent, propagative fashion and the relationships between the viruses and their thrips vectors are often specific. With the emergence of new tospoviruses, new thrips vector/tospovirus relationships have also arisen and vector specificities have changed. There is known specificity between thrips vector species and particular tospoviruses, although the cellular and molecular bases for this specificity have been elusive. Major conclusions, solutions and achievements. We demonstrated that a new tospovirus, iris yellow spot virus (IYSV) caused "straw bleaching" in onion (Allium cepa) and lisianthus necrosis in lisianthus (Eustoma russellianum). Characterization of virus isolates revealed genetic diversity among US, Brazilian, Dutch and Israeli isolates. IYSV was not seed transmitted, and in Israel, was not located in bulbs of infected plants. In the US, infected plants were generated from infected bulbs. The relationship between IYSV and Thrips tabaci was shown to be specific. Frankliniella occidentalis, the primary vector of many other tospoviruses, did not transmit IYSV isolates in Israel or the US. Furthermore, 1': tabaci populations varied in their transmission ability. Transmission was correlated to IYSV presence in thrips salivary glands. In Israel, surveys in onion fields revealed that the onion thrips, Thrips tabaci Lindeman was the predominant species and that its incidence was strongly related to that of IYSV infection. In contrast, in the U.S., T. tabaci and F. occidentalis were present in high numbers during the times sampled. In Israel, insecticides reduced onion thrips population and caused a significant yield increase. In the US, a genetic marker system that differentiates non-thrips transmissible isolates from thrips transmissible isolate demonstrated the importance of the M RNA to thrips transmission of tospoviruses. In addition, a symbiotic Erwinia was discovered in thrips and was shown to cause significant artifacts in certain types of virus binding experiments. Implications, scientific and agricultural. Rapid emergence of distinct tospoviruses and new vector relationships is profoundly important to global agriculture. We advanced the understanding of IYSV in bulb crops and its relationships with thrips vector species. The knowledge gained provided growers with new strategies for control and new tools for studying the importance of particular viral proteins in thrips specificity and transmission efficiency.
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Gottlieb, Yuval, Bradley Mullens, and Richard Stouthamer. investigation of the role of bacterial symbionts in regulating the biology and vector competence of Culicoides vectors of animal viruses. United States Department of Agriculture, June 2015. http://dx.doi.org/10.32747/2015.7699865.bard.
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Symbiotic bacteria have been shown to influence host reproduction and defense against biotic and abiotic stressors, and this relates to possible development of a symbiont-based control strategy. This project was based on the hypothesis that symbionts have a significant impact on Culicoides fitness and vector competence for animal viruses. The original objectives in our proposal were: 1. Molecular identification and localization of the newly-discovered symbiotic bacteria within C. imicola and C. schultzei in Israel and C. sonorensis in California. 2. Determination of the prevalence of symbiotic bacteria within different vector Culicoides populations. 3. Documentation of specific symbiont effects on vector reproduction and defense: 3a) test for cytoplasmic incompatibility in Cardinium-infected species; 3b) experimentally evaluate the role of the symbiont on infection or parasitism by key Culicoides natural enemies (iridescent virus and mermithid nematode). 4. Testing the role(s) of the symbionts in possible protection against infection of vector Culicoides by BTV. According to preliminary findings and difficulties in performing experimental procedures performed in other insect symbiosis systems where insect host cultures are easily maintained, we modified the last two objectives as follows: Obj. 3, we tested how symbionts affected general fitness of Israeli Culicoides species, and thoroughly described and evaluated the correlation between American Culicoides and their bacterial communities in the field. We also tried alternative methods to test symbiont-Culicoides interactions and launched studies to characterize low-temperature stress tolerances of the main US vector, which may be related to symbionts. Obj. 4, we tested the correlation between EHDV (instead of BTV) aquisition and Cardinium infection. Culicoides-bornearboviral diseases are emerging or re-emerging worldwide, causing direct and indirect economic losses as well as reduction in animal welfare. One novel strategy to reduce insects’ vectorial capacity is by manipulating specific symbionts to affect vector fitness or performance of the disease agent within. Little was known on the bacterial tenants occupying various Culicoides species, and thus, this project was initiated with the above aims. During this project, we were able to describe the symbiont Cardinium and whole bacterial communities in Israeli and American Culicoides species respectively. We showed that Cardinium infection prevalence is determined by land surface temperature, and this may be important to the larval stage. We also showed no patent significant effect of Cardinium on adult fitness parameters. We showed that the bacterial community in C. sonorensis varies significantly with the host’s developmental stage, but it varies little across multiple wastewater pond environments. This may indicate some specific biological interactions and allowed us to describe a “core microbiome” for C. sonorensis. The final set of analyses that include habitat sample is currently done, in order to separate the more intimately-associated bacteria from those inhabiting the gut contents or cuticle surface (which also could be important). We were also able to carefully study other biological aspects of Culicoides and were able to discriminate two species in C. schultzei group in Israel, and to investigate low temperature tolerances of C. sonorensis that may be related to symbionts. Scientific implications include the establishment of bacterial identification and interactions in Culicoides (our work is cited in other bacteria-Culicoides studies), the development molecular identification of C. schultzei group, and the detailed description of the microbiome of the immature and matched adult stages of C. sonorensis. Agricultural implications include understanding of intrinsic factors that govern Culicoides biology and population regulation, which may be relevant for vector control or reduction in pathogen transmission. Being able to precisely identify Culicoides species is central to understanding Culicoides borne disease epidemiology.
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Ghanim, Murad, Joe Cicero, Judith K. Brown, and Henryk Czosnek. Dissection of Whitefly-geminivirus Interactions at the Transcriptomic, Proteomic and Cellular Levels. United States Department of Agriculture, February 2010. http://dx.doi.org/10.32747/2010.7592654.bard.
Full textAbstract:
Our project focuses on gene expression and proteomics of the whitefly Bemisia tabaci (Gennadius) species complex in relation to the internal anatomy and localization of expressed genes and virions in the whitefly vector, which poses a major constraint to vegetable and fiber production in Israel and the USA. While many biological parameters are known for begomovirus transmission, nothing is known about vector proteins involved in the specific interactions between begomoviruses and their whitefly vectors. Identifying such proteins is expected to lead to the design of novel control methods that interfere with whitefly-mediated begomovirus transmission. The project objectives were to: 1) Perform gene expression analyses using microarrays to study the response of whiteflies (B, Q and A biotypes) to the acquisition of begomoviruses (Tomato yellow leaf curl (TYLCV) and Squash leaf curl (SLCV). 2) Construct a whitefly proteome from whole whiteflies and dissected organs after begomovirus acquisition. 3) Validate gene expression by q-RTPCR and sub-cellular localization of candidate ESTs identified in microarray and proteomic analyses. 4) Verify functionality of candidate ESTs using an RNAi approach, and to link these datasets to overall functional whitefly anatomical studies. During the first and second years biological experiments with TYLCV and SLCV acquisition and transmission were completed to verify the suitable parameters for sample collection for microarray experiments. The parameters were generally found to be similar to previously published results by our groups and others. Samples from whole whiteflies and midguts of the B, A and Q biotypes that acquired TYLCV and SLCV were collected in both the US and Israel and hybridized to B. tabaci microarray. The data we analyzed, candidate genes that respond to both viruses in the three tested biotypes were identified and their expression that included quantitative real-time PCR and co-localization was verified for HSP70 by the Israeli group. In addition, experiments were undertaken to employ in situ hybridization to localize several candidate genes (in progress) using an oligonucleotide probe to the primary endosymbiont as a positive control. A proteome and corresponding transcriptome to enable more effective protein identification of adult whiteflies was constructed by the US group. Further validation of the transmission route of begomoviruses, mainly SLCV and the involvement of the digestive and salivary systems was investigated (Cicero and Brown). Due to time and budget constraints the RNAi-mediated silencing objective to verify gene function was not accomplished as anticipated. HSP70, a strong candidate protein that showed over-expression after TYLCV and SLCV acquisition and retention by B. tabaci, and co-localization with TYLCV in the midgut, was further studies. Besides this protein, our joint research resulted in the identification of many intriguing candidate genes and proteins that will be followed up by additional experiments during our future research. To identify these proteins it was necessary to increase the number and breadth of whitefly ESTs substantially and so whitefly cDNAs from various libraries made during the project were sequenced (Sanger, 454). As a result, the proteome annotation (ID) was far more successful than in the initial attempt to identify proteins using Uniprot or translated insect ESTs from public databases. The extent of homology shared by insects in different orders was surprisingly low, underscoring the imperative need for genome and transcriptome sequencing of homopteran insects. Having increased the number of EST from the original usable 5500 generated several years ago to >600,000 (this project+NCBI data mining), we have identified about one fifth of the whitefly proteome using these new resources. Also we have created a database that links all identified whitefly proteins to the PAVEdb-ESTs in the database, resulting in a useful dataset to which additional ESTS will be added. We are optimistic about the prospect of linking the proteome ID results to the transcriptome database to enable our own and other labs the opportunity to functionally annotate not only genes and proteins involved in our area of interest (whitefly mediated transmission) but for the plethora of other functionalities that will emerge from mining and functionally annotating other key genes and gene families in whitefly metabolism, development, among others. This joint grant has resulted in the identification of numerous candidate proteins involved in begomovirus transmission by B. tabaci. A next major step will be to capitalize on validated genes/proteins to develop approaches to interfere with the virus transmission.
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Freeman, Stanley, and Russell J. Rodriguez. The Interaction Between Nonpathogenic Mutants of Colletotrichum and Fusarium, and the Plant Host Defense System. United States Department of Agriculture, September 2000. http://dx.doi.org/10.32747/2000.7573069.bard.
Full textAbstract:
The intent of this proposal was to study the interaction between nonpathogenic mutants of Colletotrichum magna and Fusarium oxysporum, and the cucurbit host defense system. We had shown previously that a nonpathogenic endophytic mutant path- 1 of C. magna, caused no visible disease symptoms but protected watermelon seedlings from disease caused by the wildtype isolate and F. o. niveum. Objectives were: 1) Determine the microscopic, biochemical and molecular genetic interaction between "protected" (path- 1 colonized) cucurbit hosts and wildtype isolates of C. magna; 2) Isolate non-pathogenic mutants of F.o. melonis and test feasibility for protecting plants against fungal diseases. We found that path-1 caused no visible disease symptoms in cucurbit seedlings but conferred disease resistance against pathogenic isolates of C. magna, C. orbiculare, and F. oxysporum. Disease resistance conferred by path-1 correlated to a decrease in the time of activation of host defense systems after exposure of path-1 colonized plants to virulent pathogens. This was determined by monitoring the biochemical activity of PAL and peroxidase, and the deposition of lignin. It appears that path-1-conferred disease resistance is a multigenic phenomenon which should be more difficult for pathogen to overcome than single gene conferred resistance. Based on the benefits conferred by path-1, we have defined this mutant as expressing a mutualistic lifestyle. REMI (restriction enzyme-mediated integration) nonpathogenic mutants were also isolated using pHA1.3 plasmid linearized with Hind III and transformed into wildtype C. magna. The integrated vector and flanking genomic DNA sequences in REMI mutant R1 was re-isolated and cloned resulting in a product of approximately 11 kb designated pGMR1. Transformations of wildtype C. magna with pGMR1 resulted in the same non-pathogenic phenotype. A nonpathogenic mutant of F.o. melonis (pathogenic to melon) was isolated that colonized melon plants but elicited no disease symptoms in seedlings and conferred 25 - 50% disease protection against the virulent wildtype isolate. Subsequently, nonpathogenic mutant isolates of F.o. niveum (pathogenic to watermelon) were also isolated. Their protection capacity against the respective wildtype parent is currently under investigation. This research has provided information toward a better understanding of host-parasite interactions; specifically, endophytes, pathogens and their hosts. It will also allow us to assess the potential for utilizing nonpathogenic mutants as biological control agents against fungal pathogens and isolating molecular genetic factors of pathogenicity in Fusarium.