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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Contribuição ao controle biológico de Rhynchophorus palmarum - atividade de vôo, eficiência de autoinoculação e caracterização molecular de isolados de Beauveria bassiana / Contribution to the biological control of Rhynchophorus palmarum - flight activity, autoinoculation efficiency and molecular characterization of Beauveria bassiana

Mendonça, Marcelo da Costa 28 February 2007 (has links)
The coleoptera Rhynchophorus palmarum (L.), vulgarly known as palm weevil is considered on of mainly pest of several palm trees of economic importance. In coconut tree their larvae destroy the plant culms and their adults act like a vector of nematode Bursaphelenchus cocophilus that cause the red ring disease. With the objective of subside the practices of biological control of R. palmarum already utilized it was carried out tests aiming to determine the flight activity of the insect in coconut fields; to validate the technique of autoinoculation of adults of R. palmarum using traps like vegetal traps bait inoculated with the Beauveria bassiana enthomopatogenic fungi; and to characterize genetically isolates of the fungi by molecular makers of RAPD, microsatellites and ITS-DNAr. To determine the flight activity of the insect it was installed, around the commercial field, traps of capture/monitoring for population of R. palmarum adult’s insect, containing attractive feed (culms of sugar cane) added with pheromone of aggregation. For the autoinoculation tests it was used the randomized statistical design, in a factorial scheme 3x4 (3 spores concentration of the fungi and 4 periods of autoinoculation), using four replications constituted by 5 pairs of males and females. The insects were separated, cleaned with distilled water and transfer to buckets with sugar cane culms inoculated with B. bassiana on concentrations 107, 108 and 109 spores/mL of suspension), keeping in contact with the inoculums for 45min.; 90min.; 3h00 and 6h00. After this period of exposition the insects were individualized being the mortality/infection evaluated for 20 days. For genetic characterization it was used 11 isolates obtained from monospores cultures that posterior were inoculated in a liquid medium at 25ºC±1ºC under constant shaking in dark conditions. After seven days the mycelium were filtered, lyophilized and after DNA extracted in SDS buffer at 10%. It was tested 20 decamer primers of arbitrary sequence of IDT Company. The amplifications were carried out in termocycler (Biometra/Unisciense) programmed for initial temperature of 94°C for 5min. and 45 cycles of: 94°C for 1min., 36°C for 2min. and 72°C for 1min.. For microsatellites analyses it was used four pairs of primers. The amplification reactions were carried out using a volume of 25µL. The amplifications consisted by one initial cycle of 94ºC and 30 cycles of 94ºC for 1min.; 50ºC for 1min. and 72ºC for 2min., and a end cycle of 72ºC for 7min.. The amplified fragments were separated by electrophoresis in agarose gel using TBE buffer, and the gel stained with ethidium bromete (0.5µg/mL) after visualized under UV light. The insect initiates flight activity at 5h00 am through 6h00 pm o’clock occurring the population maximum at 9h00 am to11h00 am. It was verified the mortality increase of adults of R. palmarum in accord to fungi concentration and period of exposition of the inoculums. The higest index of mortality (53%) occurred nine days after the autoinoculation by B. bassiana. The RAPD analysis generated 138 polymorphic and 14 monomorphic bands being the patterns used to calculate the genetic similarity that varies of 2% to 77%. The 57.99 (Betume2-SE) and 53.96 (Mojú-PA) isolates presented high similarity (77%), followed by 64.99 (Egypt) and 53.96 (Mojú-PA), with similarity of 73% by RAPD test. For microssatellite the BC.05 and 32.91 isolates presented genetic similarity of 82%, followed by 64.99 and 57.99 with genetic similarity of 80%. It was not observed amplifications variations using ITS regions for B. bassiana isolates. / Fundação de Amparo a Pesquisa do Estado de Alagoas / O coleóptero Rhynchophorus palmarum (L.), vulgarmente conhecido como broca-doolho-do-coqueiro é considerado uma das principais pragas de palmeiras de importância econômica. Suas larvas destroem a estipe da planta e os adultos atuam como vetores do nematóide Bursaphelenchus cocophilus causador da doença “anel vermelho”. Com o objetivo de subsidiar as práticas de controle biológico do R. palmarum já empregadas, foram realizados testes visando: determinar a atividade de vôo do inseto em plantios de coco; validar a técnica de autoinoculação de adultos de R. palmarum usando armadilhas com iscas vegetais inoculadas com o fungo entomopatogênico Beauveria bassiana e caracterizar geneticamente isolados do fungo por meio de marcadores moleculares do tipo RAPD, microssatélite e ITS-DNA. Para determinar a atividade de vôo do inseto foram instaladas, na periferia de pomares comerciais de coco, armadilhas de captura/monitoramento da população de adultos de R. palmarum, contendo atrativo alimentar (colmos de cana-de-açúcar) mais feromônio de agregação. Nos testes de autoinoculação utilizou-se o delineamento experimental inteiramente casualizado, em esquema fatorial 3x4 (3 concentrações do fungo e 4 tempos de autoinoculação), com 4 repetições de 5 casais. Os insetos foram separados, limpos em água destilada e transferidos para baldes contendo cana-de-açúcar inoculada com B. bassiana nas concentrações padronizadas (107, 108 e 109 esporos/mL de suspensão), permanecendo em contato com o inóculo por 45min.; 90min.; 3h00 e 6h00. Após o período de exposição ao fungo, os insetos foram individualizados, sendo a mortalidade/infecção avaliada por 20 dias. Na caracterização genética foram utilizados 11 isolados, para os quais foram obtidas culturas monospóricas que posteriormente foram repicadas, em meio líquido a 25ºC±1ºC, em agitação constante e no escuro. Após sete dias os micélios foram filtrados, liofilizados e em seguida seu DNA genômico extraído em tampão de extração SDS 10%. Foram testados 20 primers decâmeros de seqüência arbitrária da marca IDT. As amplificações foram realizadas em termociclador (Biometra/Unisciense) programado com temperatura inicial de 94°C por 5min. e 45 ciclos a 94°C por 1min., 36°C por 2min. e 72°C por 1min.. Para as análises de microssatélites foram empregados quatro pares de primers. As reações de amplificação foram feitas em um volume de 25µL. As amplificações consistiram de um ciclo inicial de 94ºC e 30 ciclos de: 94ºC por 1min.; 50ºC por 1min. e 72ºC por 2min., ao final 1 ciclo de 72ºC por 7min. Os fragmentos amplificados foram separados em gel de agarose, submetidos à eletroforese em tampão TBE, corados com brometo de etídio (0,5 µg/mL) e visualizados sob luz UV. Observou-se que o inseto inicia sua atividade de vôo as 5h00 até às 18h00, ocorrendo um pico populacional máximo das 9h00 às 11h00. Verificou-se uma mortalidade crescente de adultos de R. palmarum em função do aumento da concentração do fungo e dos tempos de exposição ao inóculo. O maior índice de mortalidade (53%) ocorreu nove dias após a autoinoculação do inseto. As análises de RAPD geraram 138 bandas polimórficas e 14 monomórficas, sendo os padrões empregados para o cálculo das similaridades genéticas que variaram de 2% a 77%. Os isolados 57.99 (Betume2-SE) e 53.96 (Moju-PA) apresentaram maior similaridade (77%), seguidos de 64.99 (Egito) e 53.96 (Moju-PA), com uma similaridade de 73% pelo teste de RAPD. Enquanto que para o microssatélite os isolados BC.05 e 32.91 apresentaram maior similaridade genética (82%), seguidos de 64.99 e 57.99 com similaridade genética de 80%. Não foram observadas variações na amplificação das regiões ITS de DNAr para os isolados de B. bassiana.
112

Field and Bioassay Evaluations of Elm Flea Weevil (<i>Orchestes steppensis</i> Korotyaev) Adult Feeding Preference and Larval Mine Presence among New American (<i>Ulmus americana</i>) and Hybrid Elm (<i>Ulmus</i> spp.) Cultivars

Radl, James 10 December 2018 (has links)
No description available.
113

Host selection behavior of the adult parasitoid Microctonus hyperodae Loan (Hymenoptera:Braconidae:Euphorinae) and the egg parasitoid Anaphes victus Huber (Hymenoptera:Mymaridae), parasitoids of the carrot weevil, Listronotus oregonensis LeConte (Coleoptera:Curculionidae)

Cournoyer, Michel, 1976- January 2003 (has links)
No description available.
114

Evaluation of strains of Bacillus thuringiensis as biological control agents of the adult stages of the carrot weevil, Listronotus oregonensis (Coleoptera:Curculionidae)

Saade, Fabienne Eugenie Joseph January 1993 (has links)
No description available.
115

Mathematical models for the population dynamics and management of the carrot weevil, Listronotus oregonensis (LeConte) (Coleoptera:Curculionidae)

Zhao, Dingxin January 1990 (has links)
No description available.
116

Developing remote sensing approaches for integrated pest and pollinator management in turfgrass

Bradley, Shannon Grace 06 September 2023 (has links)
Golf courses can expand hundreds of acres, making scouting for both pests and beneficial insect populations a time-consuming task. Scouting for insects is labor-intensive, potentially damaging, but is an integral part of an integrated pest and pollinator management (IPPM) plan. Virginia golf courses are currently using remote sensing and light reflectance to detect non-insect pests in turfgrass. This thesis aims to develop remote sensing and light reflectance methods to aid in a turfgrass IPPM plan, to document the phenology of ABW weevil (Listronotus maculicollis Kirby, Coleoptera: Curculionidae, ABW), and to catalogue pollinator-friendly out-of-play areas. Light reflectance, the measurement of the amount of light reflected, of plants can be used as a proxy for the health of a plant. The light reflectance of turfgrass affected by ABW stress and plants in the out-of-play areas of golf courses was collected proximally and remotely, using a backpack spectrometer and an unmanned aerial vehicle (UAV), respectively. Mathematical light reflectance indices were applied and compared to insect populations in both areas to determine the correlation. The Normalized Difference Vegetation Index (NDVI), which uses red and near-infrared wavelengths to indicate stress, was found to highlight ABW stressed turfgrass. The Structure Intensive Vegetation Pigment Index (SIPI), which uses red and green wavelengths to highlight flowering plants, was found to highlight potential pollinator- friendly habitats in out-of-play areas. When applied to flights, NDVI could help in the targeted application of insecticides to combat the annual bluegrass weevil, therefore reducing their presence in the environment. The use of SIPI could highlight potential pollinator friendly habitats and therefore assist superintendents in the development of their IPPM plan. / Master of Science in Life Sciences / Scouting, such as completing visual monitoring or taking soil core samples, is an important part in the development of an integrated pest and pollinator management (IPPM) plan for Virginia golf courses; an IPPM plan focuses on control of a pest, while considering the needs of pollinators. The size of golf courses makes scouting for insect pests and beneficial insects a time-consuming task. Golf courses are currently using remote sensing, the use of drones in combination with other technology, to scout for other pests or disease. Light reflectance, the measurement of the amount of light reflected, is often used in combination with remote sensing as a proxy for the health of plants. This thesis developed remote sensing and light reflectance techniques not only to detect a common turfgrass pest, the annual bluegrass weevil (Listronotus maculicollis Kirby, Coleoptera: Curculionidae, ABW), but to also predict the presence of potential pollinator habitats in the out-of-play areas of Virginia golf courses. Instruments such as a spectrometer and a drone were used to collect light reflectance at the ground level and aerially, respectively. Ground data was collected through soap water flushes to detect adult ABW, and visual monitoring of potentially pollinating bees, beetles, butterflies, and flies. The light reflectance and ground data were compared using mathematical indices to determine if there was a relationship between the presence of insects and a particular index. Indices could be applied to drone flights that golf course superintendents are already performing, and they can use this information to highlight potential areas of insect presence. This will help them to take care not to apply insecticides in areas with pollinators or to only apply necessary insecticides where there is likely a presence of ABW. This will reduce the labor, other costs, and the environmental impact of insecticides.
117

Plant Finding Behavior of Phytophagous Insects and Biological Control of Aquatic Plants

Reeves, Justin 24 September 2010 (has links)
No description available.
118

Impact of Rhinocyllus conicus Froelich (Coleoptera:Curculioniadae) on the reproduction of Carduus thistles in Virginia

Surles, Walter Wayne 11 June 2009 (has links)
Musk thistle (Carduus nutans) seed production from early developing (terminal and first lateral) heads was reduced by 10% in 1973 and 75% in 1974 due to larval feeding of Rhinocyllus conicus. This was caused by heavy infestation of the early heads (45% in 1973, 70% in 1974) with a subsequent 5-fold increase in the number of weevil pupation chambers in these heads. Total seed production was reduced by 35-36% in both years despite increased plant vigor due to better growing conditions in 1974. Larval feeding reduced viability of mature musk thistle seeds. Plumeless thistle (C. acanthoides) seed production from early heads decreased only 5% in 1973 and 4% in 1974 due to low rates of infestation (9% in 1973, 5% in 1974). Total seed production was reduced 0.2% in 1973 and 0.1% in 1974. Weevil larvae developing in plumeless thistle heads were more heavily parasitized than those in musk thistles. Parasitoids suffered high mortality due to entrapment in weevil pupation chambers (Aliolus curculionis, 837; Bracon mellitor, 10%), and did not inhibit weevil population buildup. These combined factors resulted in successful control of musk thistle at 1 Virginia site. R. conicus showed ovipositional preference for C. nutans over C. acanthoides heads both in the laboratory and under field conditions. Oviposition of an established weevil colony was better synchronized with musk than with plumeless thistles at a site where both thistles were present. Sequentially released, overwintered R. conicus were better synchronized with Carduus thistle development because of an extended ovipositional period, but the weevils suffered reduced fecundity. Ovipositional preference was for the earlier stages of musk thistle heads. Intermediate stages of plumeless thistle heads were preferred, and larval survival was reduced because of insufficient time for weevil development and subsequent depletion of food supply. Musk thistles subjected to mechanical and R. conicus-induced damage to terminal heads were shorter than control plants and suffered reduced seed production from terminal heads. Total head and seed production per thistle were not significantly reduced. Emerging adult weevils decreased in weight relative to crowding; no difference was detected between sexes (female, 13.4mg; male, 13.8mg). / Ph. D.
119

Biology and natural control of the white pine weevil, Pissodes strobi (Peck), in Virginia

Harman, Dan M. 01 November 2008 (has links)
Ovariole development and termination of diapause in the white pine weevil were studied by dissecting weevils at various intervals throughout the winter. Old-generation adults brought into the laboratory November produced viable eggs within 5 days. New generation adults brought into the laboratory on November 4 produced viable eggs during November. Viable eggs were deposited by other new-generation adults after 10 to 15 day. at room temperature in winter. On each of the 3 collection date studied, new generation adult produced viable eggs without copulating after collection from hibernation indicating that capulation occurs in the fall. There was no evidence of progressive ovariole development throughout the winter. New generation adults which were isolated as soon as they emerged from the shoots and maintained at constant room temperature had poorly developed ovarioles by November 20 and produced no eggs. Weevil flight and dispersal through a white pine plantation was studied by releasing 409 marked weevils at a central point within a l431-tree plantation and checking every tree at 5-day intervals. Weevils flew readily at the time of re1ease. Marked weevils were recorded throughout the plantation. which extended as far as 330 feet from the release point. A few weevils were observed on scattered white pines 200-300 yards from the release point beyond a hardwood barrier. Total numbers of weevils present on the leaders increased from April 26 to May 5, after which numbers steadily decreased. By June 15, only 20 weevils were observed on the leaders. / Ph. D.
120

Ecology of Root-Feeding Insect Assemblages in Fire-Manipulated Longleaf Pine-Wiregrass Ecosystems

Dittler, Matthew Jason 23 May 2013 (has links)
Root-feeding insects can have top-down influence on vegetative composition and ecosystem processes; however, they may respond to bottom-up factors such as soil resources, site productivity, and disturbance.  My research addressed the following questions: (1) Do disturbance (fire), vegetative composition, soil resources, and fine root standing mass influence the structure of root-feeding insect assemblages? (2) What types of roots do root-feeding insects eat, and do they forage selectively?  (3) Do root-feeding insects influence fine root productivity?  To address these questions, I studied root-feeding insect assemblages in longleaf pine wiregrass (Pinus palustris-Aristida stricta) ecosystems of southwestern Georgia, U.S.A.  On a random basis, study sites were burned at least every other year (B), or left unburned (UB) for about 9 years.  Fine root productivity and root-feeding insect abundances were sampled repeatedly across 54 random plots in UB and B sites.  In Chapter 2, I characterized spatial and temporal patterns of root-feeding insect abundance, understory plant composition, soil resource availability, and fine root standing mass within each plot.  Insect population densities were low overall, but abundance, patchiness, and diversity were greater in UB sites.  Abundance patterns were significantly related to vegetative composition.  In Chapter 3, I quantified the diet of root-feeding insects by measuring the natural abundance of carbon (C) and nitrogen (N) stable isotopes in insects and fine roots.  Using 13C abundance, I examined the contribution of warm season grass roots to insect diet, relative to the proportion of warm season grass roots within adjacent root standing crop samples; 15N abundance was used to detect omnivory.  Overall, insects appeared to be non-selective herbivores and omnivores that may alter foraging behavior to maintain a mixed diet (i.e. reducing or increasing warm season grass consumption when its abundance was high or low, respectively).  The extent of omnivory varied within and among taxa.  In Chapter 4, I estimated the top-down influence of root-feeding insects on fine root productivity by comparison of ingrowth cores with or without an insecticide treatment.  I detected a weak positive effect of herbivores on the productivity of non-grass fine roots (< 10% of fine root productivity). / Ph. D.

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