Made available in DSpace on 2015-03-26T13:30:20Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1603340 bytes, checksum: 135e2fd308ff1af60f963623548c94b3 (MD5) Previous issue date: 2006-02-17 / Empresa Brasileira de Pesquisa Agropecuária / The resistance of the insect-pests to fumigants has been frequently reported in stored grains and a present is one of the great obstacles to the control programs involving the use of chemical pesticides. This study was therefore carried out to detect phosphine resistance in populations of Tribolium castaneum, Rhyzopertha dominica and Oryzaephilus surinamensis and to recognize the existence of adaptative disadvantages of these insects in the absence of phosphine, by correlating the instantaneous rate of population growth (ri) with the resistance levels observed in different populations of the species under study. Twelve distinct populations of T. castaneum, ten of R. dominica, and eight of O. surinamensis collected in the states of Goiás, Mato Grosso, Minas Gerais and São Paulo were surveyed. The bioassays for the detection of phosphine resistance were carried out following the standard method recommended by the Food and Agriculture Organization of the United Nations (FAO), which it is based on the exposure of 50 non-sexed adult insects, in four replicates, to the discriminating concentration (DC) of the fumigant for a 20 hourperiod. Later, the concentration-response bioassays were carried out generating the concentration-mortality curves that were used to estimate LC50 and LC95 of the populations pertaining to those three species. The LC50 were used to discriminate the standard population for susceptibility in each species. The measurements of the body mass, CO2 production, and instantaneous rate of population increase (ri) in each population of each species were correlated to the resistance ratio at the LD50. The resistance ratio in T. castaneum ranged from 1,0 to 186,2-fold, whereas in R. dominica it ranged from 2,0 to 71,0-fold, and the lowest one from 1,9 to 32,2-fold for O. surinamensis. The results obtained in the resistance detection bioassays pointed out ten populations of T. castaneum, nine of R. dominica and seven of O. surinamensis that were resistant to phosphine. The relationship between the body mass and CO2 production was positive and significant indicating an increase in CO2 production with the individual body mass. The same effect is observed in the interaction between the instantaneous rate of population increase (ri) and body mass. In addition, the populations with lower CO2 production showed higher resistance ratio (RR) for all species, what is related to the phosphine resistance mechanism. The populations with higher ri showed lower resistance ratio (RR). This result indicates a worse reproductive performance of the resistant populations compared with the susceptible ones. Thus, the management strategies that are based on the interruption of the phosphine fumigation over determined time for the reestablishment of the susceptibility and eventual reintroduction of the fumigant shows a good perspective as a management tactic since the resistant populations under study showed adaptative disadvantage in relation to the susceptible ones in the absence of phosphine. / A resistência a inseticidas fumigantes em insetos-praga de grãos armazenados tem sido freqüentemente registrada e, atualmente, tem se tornado um dos grandes obstáculos aos programas de controle envolvendo o uso de produtos químicos. Com isso, objetivou-se neste estudo detectar populações de Tribolium castaneum, Rhyzopertha dominica e Oryzaephilus surinamensis resistentes à fosfina, além de aferir a existência de desvantagens adaptativas destas, na ausência da fosfina, correlacionando-se produção de CO2, massa corpórea e taxa instantânea de crescimento populacional (ri), com os níveis de resistência observados nas diferentes populações das três espécies em estudo. Foram utilizadas 12 populações distintas de T. castaneum, 10 de R. dominica e oito populações de O. surinamensis, coletadas nos Estados de Goiás, Mato Grosso, Minas Gerais e São Paulo. Os bioensaios para detecção de resistência foram conduzidos conforme método-padrão, recomendado pela Food and Agriculture Organization of the United Nations (FAO), que é baseado na exposição de 50 insetos adultos, em quatro repetições, por um período de 20 horas à concentração discriminante (CD) do gás fumigante. Posteriormente, foram conduzidos bioensaios de concentração-resposta gerando, assim, as curvas de concentração-mortalidade que foram utilizados para estimar as CL50 e CL95 das populações das três espécies. As CL50, por sua vez, foram utilizadas para discriminar a população padrão de suscetibilidade de cada espécie e o nível de resistência das demais populações. A mensuração da massa corpórea, produção de CO2 e taxa instantânea de crescimento (ri) de cada população, das três espécies avaliadas, foram correlacionados à razão de resistência para CL50. A razão de resistência para CL50 em T. castaneum variou de 1,0 a 186,2 vezes, enquanto em R. dominica foi de 2,0 a 71,0 vezes e em O. surinamensis observou-se a menor variação, de 1,9 a 32,2 vezes. Os resultados obtidos nos bioensaios de detecção de resistência indicaram 10 populações de T. castaneum, nove de R. dominica e sete de O. surinamensis resistentes a fosfina. A relação entre massa corpórea e produção de CO2 foi significativa, indicando aumento na produção de CO2 com o incremento da massa corpórea dos indivíduos, nas três espécies avaliadas. O mesmo efeito é observado na interação entre taxa instantânea de crescimento populacional (ri) e a massa corpórea. As populações com menor produção de CO2 apresentaram maior razão de resistência (RR) para CL50, para as três espécies avaliadas, fato que está relacionado ao mecanismo de resistência dos insetos à fosfina. As populações com maiores valores médios de ri apresentaram menor razão de resistência (RR) para CL50, nas três espécies avaliadas. Este resultado indica pior desempenho reprodutivo das populações resistentes, em relação às populações suscetíveis na ausência do fumigante. Portanto, estratégias de manejo da resistência que são baseadas na interrupção da fumigação com fosfina, por determinado tempo visando o restabelecimento da suscetibilidade e eventual reintrodução do fumigante apresentam boa perspectiva de sucesso. Isto porque, as populações resistentes avaliadas neste estudo apresentaram desvantagens adaptativas, em relação às suscetíveis, na ausência da fosfina.

No description available.

Thesis (M.A.)--Miami University, Dept. of Geography, 2007. / Title from first page of PDF document. Includes bibliographical references (p. 67-72).

Community-based tourism (CBT) has become an important facet in the quest for sustainable tourism. CBT is a term that has been subjected to different interpretations in the academic literature. In the field, CBT continues to be supported as an approach to improve the livelihoods of local people in communities participating in tourism. With growing interest in the sustainable livelihoods approach to development, tourism researchers have begun to examine tourism as a livelihood strategy. However, there remain few case studies that have connected the sustainable livelihoods approach and tourism. More specifically, there is limited empirical evidence exploring community-based tourism as a livelihood strategy for rural communities. This research employed an exploratory mixed methods approach to investigate community-based tourism from a livelihoods perspective. The case of the Commonwealth of Dominica was examined to address the following objectives: i) to assess the approach to the development of community-based tourism on the island of Dominica; ii) to analyze residents’ perceptions of the impacts that tourism has on their community from a livelihoods perspective; and iii) to evaluate the degree of success (or failure) of community-based tourism development in Dominica. The research findings revealed that community-based tourism is a valued component of Dominica’s national tourism strategy. Since the early nineties, community involvement has been an implicit policy in the tourism development process. More recently, government-funded initiatives have provided assistance to communities across the island to develop, implement, and market community tourism products. Additionally, this research suggests that the livelihood asset pentagon presented in the Sustainable Livelihoods Framework for Tourism (Shen, Hughey, and Simmons, 2008) is an effective organizational tool for assessing the impact of tourism on communities. Future research should be directed at applying the Sustainable Livelihoods Framework for Tourism in more diverse contexts to ensure its validity and applicability. Furthermore, there is a need to develop a comprehensive Community-based Tourism Framework to assist in the monitoring and evaluation of community-based tourism projects in the field. The main conclusion drawn from this study is that the island of Dominica is on a successful path for developing community-based tourism and it has the potential to yield a number of ‘best practice’ scenarios for the Caribbean region and the globe a like.

Dominica has been recognized for its landscape containing hundreds of rivers and receiving high rainfall, and "our water belongs to the world," or so says many Dominican citizens, and their government. A schism exists in the understanding of the water resources of Dominica. Local perceptions are in conflict with regional climate change data. Where climate change research has found Dominica to be high risk for water quality and quantity, locals maintain the mindset that there is an overabundance of the resource. Local epistemologies influence governmental water management practices, which presently focus on exportation of the resource. In efforts of economic development, while trusting that there is a surplus of water, Dominica leases billions of gallons of water each year to foreign companies. A popular conception on the island is that there is an abundance of water, and therefore, it should be shared globally. This unique social construction of Dominican water has been a foundation leading to the sale of billions of gallons of fresh water to international corporations. However, the bulk exportation of water is occurring in the context of climate change, and thus, the availability of water will be impacted by changes in annual rainfall, sea level rise, increased temperatures, and more severe hurricanes. The purpose of this study is to gain a better understanding of how the social understanding of water in Dominica was constructed, and what this means in relation to resource exportation and climate change. This research-based paper explores Dominican perceptions of water abundance and sustainability.

Community-based tourism (CBT) has become an important facet in the quest for sustainable tourism. CBT is a term that has been subjected to different interpretations in the academic literature. In the field, CBT continues to be supported as an approach to improve the livelihoods of local people in communities participating in tourism. With growing interest in the sustainable livelihoods approach to development, tourism researchers have begun to examine tourism as a livelihood strategy. However, there remain few case studies that have connected the sustainable livelihoods approach and tourism. More specifically, there is limited empirical evidence exploring community-based tourism as a livelihood strategy for rural communities. This research employed an exploratory mixed methods approach to investigate community-based tourism from a livelihoods perspective. The case of the Commonwealth of Dominica was examined to address the following objectives: i) to assess the approach to the development of community-based tourism on the island of Dominica; ii) to analyze residents’ perceptions of the impacts that tourism has on their community from a livelihoods perspective; and iii) to evaluate the degree of success (or failure) of community-based tourism development in Dominica. The research findings revealed that community-based tourism is a valued component of Dominica’s national tourism strategy. Since the early nineties, community involvement has been an implicit policy in the tourism development process. More recently, government-funded initiatives have provided assistance to communities across the island to develop, implement, and market community tourism products. Additionally, this research suggests that the livelihood asset pentagon presented in the Sustainable Livelihoods Framework for Tourism (Shen, Hughey, and Simmons, 2008) is an effective organizational tool for assessing the impact of tourism on communities. Future research should be directed at applying the Sustainable Livelihoods Framework for Tourism in more diverse contexts to ensure its validity and applicability. Furthermore, there is a need to develop a comprehensive Community-based Tourism Framework to assist in the monitoring and evaluation of community-based tourism projects in the field. The main conclusion drawn from this study is that the island of Dominica is on a successful path for developing community-based tourism and it has the potential to yield a number of ‘best practice’ scenarios for the Caribbean region and the globe a like.

v, 78 leaves : photo., graphs, tables ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Entomology, Waite Agricultural Research Institute, 1978

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2018-04-03T11:23:58Z No. of bitstreams: 1 texto completo.pdf: 6246480 bytes, checksum: 22d05834752231aeab0a313c35f9fad0 (MD5) / Made available in DSpace on 2018-04-03T11:23:58Z (GMT). No. of bitstreams: 1 texto completo.pdf: 6246480 bytes, checksum: 22d05834752231aeab0a313c35f9fad0 (MD5) Previous issue date: 2016-12-22 / Várias espécies de plantas produzem misturas de compostos odoríferos e voláteis conhecidos como óleos essenciais (OEs). Existem mais de 3000 OEs relatados na literatura com aproximadamente 300 em uso comercial, incluindo OEs de espécies de Eucalyptus, um grande gênero da família Myrtaceae. Muitos OEs de espécies de Eucalyptus têm encontrado aplicações em produtos farmacêuticos, agroquímicos, flavorizantes de alimentos e perfumes, sendo que estas aplicações estão relacionadas com as suas diversas propriedades biológicas e organolépticas. Diante destes fatos, no primeiro capítulo, foi realizada uma revisão das informações mais recentes sobre composição química e atividades biológicas de OEs de diferentes espécies de Eucalyptus, sendo destacadas as atividades antimicrobianas, acaricidas, inseticidas e herbicidas. No segundo capítulo, determinou-se a composição química dos OEs das folhas de vinte e duas espécies de plantas da família Myrtaceae, cultivados em Viçosa, Minas Gerais, sendo quatorze espécies de Eucalyptus (E. andrewsii, E. siderophloia, E. nitens, E. pyrocarpa, E. phaeotricha, E. umbra, E. crebra, E. resinifera, E. cinerea, E. phoenicea, E. punctata, E. sphaerocarpa, E. pellita e o híbrido E. alba x E. tereticornis), seis espécies de Corymbia (C. citriodora, C. maculata, C. intermedia, C. henryi, C. torelliana e C. ptychocarpa), além das espécies Lophostemon confertus e Syncarpia glomulifera. As folhas foram coletadas em duas épocas, ao final da estação seca e em estação chuvosa. A identificação e a quantificação dos constituintes dos OEs foram realizadas por CG-DIC e CG/EM. Algumas espécies estudadas mostraram constituir fontes promissoras de terpenos bioativos e produtos importantes na indústria química como C. maculata, C. torelliana, E. umbra, E. phoenicea e S. glomulifera que apresentaram elevados teores de α- e β-pineno, assim como C. citriodora que apresentou alto teor de citronelal nos OEs nas amostras coletadas ao final da estação seca. Os OEs das espécies E. cinerea, E. punctata, E. resinifera, E. phaeotricha, e o híbrido E. alba x E. tereticornis apresentaram altos níveis de 1,8-cineol e a espécie de E. pyrocarpa apresentou teor considerável dos isômeros de eudesmol em seus OEs. Este trabalho indica que a composição química dos OEs pode variar muito em função da época da coleta do material vegetal, além de apresentar relatos inéditos da composição viiquímica dos OEs das espécies E. andrewsii, C. henryi, E. phoenicea, C. ptychocarpa, E. pyrocarpa e o híbrido E. alba x E. tereticornis. No terceiro capítulo a investigação da atividade inseticida dos OEs contra Plutella xylostella (L.) (Lepidoptera: Plutellidae), principal praga de brássicas no mundo, mostrou que o OE mais ativo foi obtido a partir de folhas de C. citriodora coletadas durante a estação seca, que apresentou como componentes principais citronelal (86,8%) e (-)-isopulegol (4,7%). Com 30 μg mg -1 de inseto, este OE causou 80% de mortalidade de P. xylostella e apresentou atividade superior (DL 50 = 21,53 μg mg -1 de inseto, DL 90 = 42,29 μg mg -1 de inseto) ao óleo de neem (DL 50 = 30,79 μg mg -1 de inseto, DL 90 = 161,11 μg mg -1 de inseto) utilizado como controle positivo nos bioensaios, além de exercer rápido controle sobre P. xylostella. Estes OEs apresentam baixa toxicidade para Solenopsis saevissima (predador natural), mas alta toxicidade para Tetragonisca angustula (polinizador). Os bioensaios contra P. xylostella demonstraram efeito sinérgico entre os principais componentes do OE de C. citriodora da estação seca. Conforme a investigação, acima descrita, sugere-se que os OEs de C. citriodora possam ser uma alternativa ao controle por inseticidas de P. xylostella. Em outra investigação, no capítulo 4, a atividade inseticida dos OEs foram observadas em bioensaios de contato e fumigação contra Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), um dos principais insetos que causam grande perda em grãos armazenados em todo mundo. O OE mais ativo foi obtido a partir de folhas de E. resinifera coletadas após a estação seca, que apresentaram como componentes principais 1,8-cineol (59,3%), p-cimeno (12,9%) e α-pineno (9,7%). Nos bioensaios de contato numa dose de 30 μg mg -1 de inseto, este OE causou 83,3% de mortalidade a R. dominica, sendo que sua eficácia (DL 50 = 17,08 μg mg -1 de inseto; DL 95 = 56,17 μg mg - de inseto) foi inferior à do Actellic (DL 50 = 0,49 μg mg -1 de inseto; DL 95 = 1,14 μg mg -1 de inseto), utilizado como controle positivo. Já nos bioensaios de fumigação a mortalidade causada pelo OE de E. resinifera a 150 μL L -1 foi de 90,0%, apresentando eficácia (CL 50 = 70,55 μL L -1 ; CL 95 = 266,40 μL L -1 ) superior à do Actellic (CL 50 = 154,74 μL L -1 ; CL 95 = 334,95 μL L -1 ). O TL 50 sobre adultos de R. dominica para o OE de E. resinifera foi de 1,7 horas no bioensaio de contato (DL 95 de 56,17 μg mg -1 de inseto) e de 12,6 horas no bioensaio de fumigação (CL 95 de 266,40 μL L -1 ). Os bioensaios mostraram que o 1,8-cineol é o responsável pelo efeito fumigante do OE de E. resinifera, já em relação ao bioensaio de contato, não foi possível determinar o responsável pelo efeito tóxico, sendo, provavelmente, a toxicidade de contato do OE de E. resinifera a R. dominica causada pelo sinergismo entre substâncias presentes no OE. De acordo com os resultados obtidos neste trabalho, sugere-se que os OEs de E. resinifera apresentam potencial para ser utilizado como uma alternativa aos inseticidas comerciais no controle de R. dominica. / Several species of plants produce mixtures of odoriferous and volatile compounds known as essential oils (EOs). There are more than 3000 EOs reported in the literature, with approximately 300 in commercial use, including EOs of Eucalyptus species, a large genus of the Myrtaceae family. Many EOs of Eucalyptus species have found applications in pharmaceuticals, agrochemicals, food flavorings and perfumes, these applications being related to their diverse biological and organoleptic properties. In the first chapter, a review of the latest information concerning the chemical composition and biological activities of EOs from different species of Eucalyptus, with emphasis on antimicrobial, acaricidal, insecticidal and herbicidal activities. In the second chapter, the EOs contained in the foliage of twenty-two species of plants of the Myrtaceae family were chemically analyzed. Fourteen species of Eucalyptus (E. andrewsii, E. siderophloia, E. nitens, E. pyrocarpa, E. phaeotricha, E. umbra, E. crebra, E. resinifera, E. cinerea, E. phoenicea, E. punctata, E. sphaerocarpa, E. pellita and E. alba x E. tereticornis hybrid), six species of Corymbia (C. citriodora, C. maculata, C. intermedia, C. henryi, C. torelliana and C. ptychocarpa), as well as the species Lophostemon confertus and Syncarpia glomulifera. These were grown in Viçosa, Minas Gerais, Brazil and collected during two seasons: at the end of the dry and rainy seasons. Identification and quantification of EOs constituents was performed by GC-FID and GC/MS. Some species have been shown to be promising sources of bioactive terpenes and important products in the chemical industry, such as C. maculata, C. torelliana, E. umbra, E. phoenicea and S. glomulifera, which presented high levels of α- and β- pinene, as well as C. citriodora that presented citronellal content in OEs samples collected at the end of the dry season. The E. cinerea, E. punctata, E. resinifera, E. phaeotricha and the hybrid E. alba x E. tereticornis showed high levels of 1,8-cineol and E. pyrocarpa species presented a considerable content of the isomers of eudesmol in their OEs. Furthermore they indicate that the EO’s chemical composition varies greatly depending on the harvesting season of the vegetable samples. Additionally, it reports unprecedented data on EOs chemical composition for species such as E. andrewsii, C. henryi, E. phoenicea, C. ptychocarpa, E. pyrocarpa and the hybrid E. alba x E. tereticornis. In the third chapter the investigation of the insecticidal activity of EOs against Plutella xylostella (L.) (Lepidoptera: Plutellidae), the main brassica pest worldwide, showed that the most active EOs was obtained from leaves of C. citriodora collected during the dry season and present as the main components citronellal (86.8%) and (-)-isopulegol (4.7%). At 30 μg mg -1 of insect, this EO caused 80% mortality of P. xylostella and presented superior activity (LD 50 = 21.53 μg mg -1 of insect; LD 90 = 42.29 μg mg -1 of insect) than neem oil (LD 50 = 30.79 μg mg -1 of insect; LD 90 = 161.11 μg mg - of insect) used as positive control in the bioassays. In addition, dry season leaf C. citriodora EO exert fast control on P. xylostella. The effects of this EO were also evaluated against Solenopsis saevissima, a natural predator of P. xylostella, and Tetragonisca angustula, a pollinator. While C. citriodora EO present low toxicity on S. saevissima, high toxicity was noticed against T. angustula. Bioassays demonstrated synergistc effects between the main components of dry season leaf C. citriodora EO. Based on the findings described in this investigation, it is suggested that C. citriodora EOs can be an alternative to insecticide control. In another investigation, in chapter 4, the insecticidal activity of EOs was observed in contact and fumigation bioassays against Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), one of the insects that most damage stored grains worldwide. The most active EO was obtained from the foliage of E. resinifera, of which the main components are 1.8-cineol (59.3%), p- cymene (12.9%) and α-pinene (9.7%). In contact bioassays at 30 μg mg -1 per insect, this EO lead to 83.3% mortality of R. dominica (with an efficiency of LD 50 = 17.08 μg mg -1 per insect; LD 95 = 56,17 μg mg -1 per insect). This was lower than that of the commercial insecticide Actellic (LD 50 = 0,49 μg mg -1 per insect); (LD 95 = 1,14 μg mg -1 per insect) was used as a positive benchmark. Mortality rates of 90.0% were achieved during fumigation bioassays (150 μL L -1 ) by E. resinifera’s EO equal to a performance of (LC 50 = 70.55 μL L -1 ; LC 95 = 266.40 μL L -1 ) which exceeds Actellic’s (LC 50 = 154.74 μL L -1 ; LC 95 = 334.95 μL L -1 ). The LT 50 of E. resinifera EO on R. dominica adults was of 1.7 hours for contact bioassays (LD 95 of 56,17 μg mg -1 per insect) versus 12.6 hours during fumigation bioassays (LC 95 of 266,40 μL L -1 ). Bioassays prove that 1.8-cineol is responsible for the EO’s fumigant properties of E. resinifera. Contact bioassays, however, were unable to identify the toxicity source (presumably the synergy between substances present in the EOs of both E. resinifera and R. dominica). Results obtained, suggest that E. resinifera’s EOs show potential as an alternative to commercial insecticides against R. dominica.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-05-18T14:44:25Z No. of bitstreams: 1 Valdeany Nubia de Souza.pdf: 611050 bytes, checksum: 5f66ab9f1e33892b5af11791a89b157b (MD5) / Made available in DSpace on 2017-05-18T14:44:25Z (GMT). No. of bitstreams: 1 Valdeany Nubia de Souza.pdf: 611050 bytes, checksum: 5f66ab9f1e33892b5af11791a89b157b (MD5) Previous issue date: 2015-02-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The coleoptera Rhyzopertha dominica F. (Bostrichidae) is one of the main pests of stored products, causing qualitative and quantitative losses as reducing the nutritional and commercial value of the product. With the need to find alternatives to the use of chemical control, due to the development of insect resistance and the possibility of contamination of the products, the use of natural substances such as essential oils is proving itself as a promising alternative. Thus, this study aims to evaluate the insecticide activity of essential oils of basil (Ocimum basilicum), bitter orange (Citrus aurantium), Mint (Mentha spicata) and Velaminho (Croton pulegiodorus) on adult R. dominica in stored corn. Fumigation, contact and repellency tests were performed. The fumigation test was performed in containers made of glass with lids containing 10 individuals of R. dominica, in which the essential oils were applied in various concentrations (μL / L air) and after 48 hours of exposure to these oils the percentage of insect mortality was evaluated. For the contact test Petri dishes (6 cm Ø) were used with the essential oils diluted in 500 μL acetone and applied to filter paper of the same diameter, in different concentrations. After 24 hours the mortality of insects was evaluated. To evaluate the repellent effect two sublethal concentrations of each oil were used, estimated from previous tests, which are lower than the LC50. The tests were conducted in Petri dishes (Ø 6 cm) where filter paper discs were divided in half by applying one of the halves some of the oils concentrations (treatments), diluted in 500 μL acetone, and on the other only acetone (control). R. dominica individuals were released in the center of the plate and after 24 hours the metering was performed to count the insects found in each of the discs. In the fumigation test, in accordance with the LC50 and CL100, the toxicity of essential oils decreased in the following order: O. basilicum> M. spicata> C. pulegiodorus> C. aurantium. The essential oils of O. basilicum and M. spicata showed higher insecticidal effect on R. dominica, but the essential oils of C. aurantium and C. pulegiodorus promoted mortality in R. dominica only at higher concentrations. For the contact test, according to CL50, the toxicity of essential oils decreased in the following order: M. spicata> C. pulegiodorus> O. basilicum> C. aurantium. The essential oils of C. pulegiodorus and M. spicata showed higher toxicity by contact, while for the repellency test all essential oils were considered repellent. However, all the oils studied in this work showed insecticidal properties to promote the control of R. dominica and demonstrated potential use in the management of this coleoptera. / O coleóptero Rhyzopertha dominica F. (Bostrichidae) é uma das principais pragas de produtos armazenados, ocasionando perdas qualitativas e quantitativas, como redução dos valores nutricionais e comerciais do produto. Com a necessidade de se buscar alternativas ao uso do controle químico, devido ao desenvolvimento de resistência aos insetos e à possibilidade de contaminação dos produtos, o uso de substâncias naturais como os óleos essenciais vem se mostrando uma alternativa promissora. Neste sentido, este trabalho tem o objetivo de avaliar a atividade inseticida de óleos essenciais de Manjericão (Ocimum basilicum), Laranja amarga (Citrus aurantium), Hortelã (Mentha spicata) e Velaminho (Croton pulegiodorus) sobre adultos de R. dominica em milho armazenado. Foram realizados testes de fumigação, contato e repelência. O teste de fumigação foi realizado em câmaras compostas por recipientes de vidro com tampa contendo 10 indivíduos de R. dominica, nas quais os óleos essenciais foram aplicados em diferentes concentrações (μL / L de ar) e após 48h de exposição aos óleos foi avaliada a percentagem de mortalidade dos insetos. Para os testes de contato foram utilizadas placas de Petri (6 cm Ø), sendo os óleos essenciais diluídos em 500 μL de acetona e aplicados em papel filtro de mesmo diâmetro, em diferentes concentrações. Após 24h foi avaliada a mortalidade dos insetos. Para a avaliação do efeito repelente foram utilizadas duas concentrações subletais de cada óleo, estimadas através de testes prévios, sendo estas inferiores à CL50. Os testes foram feitos em placas de Petri (6 cm Ø) onde discos de papel-filtro foram divididos ao meio aplicando-se em uma das metades uma das concentrações dos óleos (tratamentos), diluídos em 500 μL de acetona, e na outra apenas a acetona (testemunha). No centro da placa foram liberados os indivíduos de R. dominica e decorridas 24h foi realizada a contagem dos insetos encontrados em cada parte do disco. Nos testes de fumigação, de acordo com as CL50 e CL100, a toxicidade dos óleos essenciais decresceu na seguinte ordem: O. basilicum > M. spicata > C. pulegiodorus > C. aurantium. Os óleos essenciais de O. basilicum e M. spicata apresentaram maior efeito inseticida sobre R. dominica, mas os óleos essenciais de C. aurantium e C. pulegiodorus promoveram a mortalidade em R. dominica apenas em concentrações mais altas. Para o teste de contato, de acordo com as CL50, a toxicidade dos óleos essenciais decresceu na seguinte ordem: M. spicata > C. pulegiodorus > O. basilicum > C. aurantium. Os óleos essenciais de C. pulegiodorus e M. spicata apresentaram maior toxicidade por contato, enquanto que para o teste de repelência todos os óleos essenciais foram considerados repelentes. Contudo todos os estudados no presente trabalho apresentaram propriedades inseticidas para promover o controle de R. dominica e demonstraram potencial de utilização no manejo deste coleóptero.

Seagrass meadows, like coral reefs, are in decline globally but are often neglected in marine policy and conservation despite their equally critical ecosystem services. Both habitats can be heavily impacted by wave surges, rainfall-induced earth movement and flooding, changes to water temperature, salinity, and acidity, and increased levels of turbidity—all occurring at increased rates due to a changing global climate. We demonstrate that multispectral satellite imagery, geospatial tools, and classification techniques can be used to inform management by identifying and quantifying changes in seagrass distribution and the presence of sediment-related threats. Results from Dominica indicate near-shore seagrass habitat area increased by 195.7 hectares between 2016 and 2019, suggesting a continued expansion of Halophila stipulacea. Further analysis showed 22.4 hectares of accreted coastal sediment and 1362.2 hectares of suspended sediment captured, placing 424.4 hectares of sensitive reef area at risk of experiencing tissue abrasion or reduced photosynthetic activity. Our methods can be used by marine resource managers and policy makers to inform decisions relating to fisheries production, emissions trading, disaster risk mitigation, and invasive species monitoring, facilitating sustainable growth in the blue economy.