Essais sur des questions internationales en économie de l'environnement

Cette thèse est constituée de trois articles. Le premier étudie le problème de pollution globale dans un contexte environnemental incertain. Le deuxième article traite des accords internationaux sur l'environnement. Le troisième article montre comment la libéralisation du commerce peut affecter le bien-être et les taxes sur la pollution dans un monde où les pays sont hétérogènes et la pollution transfrontalière. Dans le premier article, je considère un monde dans lequel les pays souffrent uniformément de la pollution globale. Ils font face à une menace continuelle de voir les dommages causés par cette pollution globale s'accroître subitement de façon irréversible. Je caractérise le niveau des émissions, le stock de pollution, et le niveau de bien-être actualisé en équilibres coopératif et non-coopératif. L'objectif visé est d'analyser l'impact de ce type d'incertitude sur les équilibres issus des comportements stratégiques des pays. Je trouve que cette incertitude peut avoir un effet significatif sur ces équilibres. Les pays réduisent leurs émissions pour atténuer leur exposition à cette menace. Plus la menace est grande, plus les pays ajustent leurs émissions afin de réduire le stock de pollution globale. Cependant, en dépit du fait que cette incertitude diminue le bien-être net initial, elle peut à long terme avoir un effet net positif sur le bien-être. Le deuxième article étend la classe des modèles dynamiques standards traitant des accords internationaux sur l'environnement au cas où la durée de la période d'engagement à de tels accords est un paramètre que l'on peut varier de façon exogène. Nous y étudions les évolutions dans le temps de la taille des coalitions stables, du stock de pollution et du taux d'émissions en fonction de la durée d'engagement. Nous montrons que la longueur de la période d'engagement a un effet très significatif sur l'équilibre. Trois intervalles de durée d'engagement sont identifiés pour lesquels l'équilibre et sa dynamique diffèrent considérablement. Alors que pour des durées de la période d'engagement très longues on observe des coalitions stables constituées d'un petit nombre de pays, si ces durées sont suffisamment courtes on peut observer un niveau de coopération élevé. Les durées d'engagement entre ces deux extrêmes sont caractérisées par une relation inverse entre la durée de la période d'engagement et la taille des coalitions stables. Ces faits portent à croire qu'il faudrait accorder une attention toute particulière au choix de la durée d'engagement lors de l'élaboration de tels accords internationaux. Le troisième article s'inscrit dans un contexte où les activités de production des pays potentiellement hétérogènes génèrent de la pollution qui peut traverser les frontières et nuire au bien-être des pays impliqués. Dans chacun de ces pays, l'état impose des taxes sur la pollution aux firmes polluantes et des tarifs à l'importation afin de corriger cette distorsion. Ce papier a pour but d'évaluer les effets que pourrait avoir une diminution des tarifs douaniers sur la production, les taxes sur la pollution et le bien-être de ces pays. La littérature existante a étudié ce problème, mais seulement dans le cadre d'un commerce bilatéral entre pays identiques. Cet article fournit un cadre d'analyse plus réaliste dans lequel les pays ne seront pas nécessairement identiques et où le commerce pourra être multilatéral. Il devient alors possible de mettre en évidence le biais introduit en négligeant ces deux facteurs. Dans ce nouveau contexte, je montre qu'une réduction des tarifs d'importation n'augmente pas nécessairement la production; elle peut aussi nuire au bien-être, même si la pollution est purement locale.

Assessment of the strategies of organic fruit production and fruit drying in Uganda

Organic agriculture in Uganda is developing at a fast pace and despite this trend Uganda is still unable to produce enough fresh and dry organic fruits mainly pineapple to meet the exporters demand. This current research investigated the strategies of farmers at production level by assessing the pros and cons of fruit growing, organic agriculture and fruit drying in order to understand the underlying causal factor for the low production of organic dry fruits in a major fruit producing district of Uganda. The study was carried out in two separate and distinctive areas; one which only produces and export fresh organic pineapple and the other which exports dried fruits (mainly pineapple and papaya). About 10% of the farmers in the two study areas were surveyed using questionnaires which were further followed by semi-structured interviews and participatory rural appraisals activities with various types of farmers in order to understand the different decisions and strategies of farmers. 82% and 74% of farmers in the two study areas grew fruits as it gave better economic returns and for 77% and 90% respectively in the two study areas, the reasons for growing fruit was the ease of selling compared to other crops. All the farmers were relying on coffee husk for growing organic pineapples. However, 50% of the farmers want to grow pineapples (either organic or conventional) but couldn't afford to buy coffee husk. Fruit drying was mainly a strategy to utilize cheap fruits during harvesting seasons for value addition. 71% and 42% of farmers in the two study areas wanted to dry fruits but it was beyond their economic capacity to buy the driers. Decision of the farmers whether to grow fruits or cereals, organic or conventional agriculture and selling the fruits as fresh or dry were dependent mainly on the economic, knowledge and resource availability of each type of practices. It is concluded that the main barrier for an increase in the production of organic dried fruits is at the processing level, and the limited capacity for investments in drying facilities.

Addressing uncertainty in adaptation planning for agriculture

We present a framework for prioritizing adaptation approaches at a range of timeframes. The framework is illustrated by four case studies from developing countries, each with associated characterization of uncertainty. Two cases on near-term adaptation planning in Sri Lanka and on stakeholder scenario exercises in East Africa show how the relative utility of capacity vs. impact approaches to adaptation planning differ with level of uncertainty and associated lead time. An additional two cases demonstrate that it is possible to identify uncertainties that are relevant to decision making in specific timeframes and circumstances. The case on coffee in Latin America identifies altitudinal thresholds at which incremental vs. transformative adaptation pathways are robust options. The final case uses three crop–climate simulation studies to demonstrate how uncertainty can be characterized at different time horizons to discriminate where robust adaptation options are possible. We find that impact approaches, which use predictive models, are increasingly useful over longer lead times and at higher levels of greenhouse gas emissions. We also find that extreme events are important in determining predictability across a broad range of timescales. The results demonstrate the potential for robust knowledge and actions in the face of uncertainty.

Eficiência de diferentes ramais de pulverização e volumes de calda no controle de Brevipalpus phoenicis na cultura do café

Efficiency of different spraying lances and spraying volumes on the control of Brevipalpus phoenicis in coffee crops. The mite Brevipalpus phoenicis is found on coffee plantations in Brazil since the 1950's. Responsible for indirect losses due to its role as vector of a virus disease, this mite species often requires control measures, the most common based on mitecide spraying. It was evaluated the mortality of B. phoenicis due the coverage of spraying liquid applied on coffee plants, with two types of lances used in air assisted sprayers and four spraying. volumes. Treatments were applied with mitecide abamectin (Vertimec 18 CE (R) at 0.4 L per hectare), in volumes of 250, 400, 550 and 700 L per hectare, with two types of lances for the nozzles. The control efficiency against B. phoenicis, deposition and coverage by spray liquid on coffee plants was evaluated. Experimental delineation was in randomized blocks, with eight treatments plus a check plot in four replications. The statistical analysis was carried in a factorial scheme 2x4+1. No significant differences in the number of mites were found between treatments. As regards spraying liquid deposition, it was observed an increment with increasing spraying volumes, with the plant tops showing the best deposition of spraying liquid. The duplication of the lances (nozzle branches) resulted in a significant increase in control efficiency for B. phoenicis compared with conventional branch and with check plot, without dependence of spraying volume.

Estudos biológicos de cochonilhas do gênero Planococcus (Hemiptera: Pseudococcidae) em diferentes hospedeiros

This work was carried out to study the development of populations of the genus Planococcus in different plant species, aiming at the verification of host specificity. The mealybugs Planococcus minor were obtained from cocoa plants (Theobroma cacao L.) and coffee crop (Coffea canephora L.), and Planococcus citri from citrus seedlings (Citrus sinensis L. Osbeck). Single eggs were transferred to Petri dishes containing leaf discs of cocoa (T. cacao cultivar Catongo), coffee (Coffea arabica L. cultivar Mundo Novo) and citrus (C. sinensis cultivar Pera Rio). They were maintained on a water-agar slide at 1%, with the abaxial surface turned upwards. The dishes were sealed with a PVC plastic film and kept in climatized chambers regulated at 25 [plus or minus] 1[degrees] C, 70 [plus or minus] 10% RH and 12 hours of photophase. For the mealybugs coming from cocoa plants, the citrus substrate prolonged the nymphal development of the males (26.0 days). In the nymphal period of females and males coming from coffee plants, the coffee substrate allowed a shorter duration of that period (19.2 and 21.3 days, respectively) and, in addition to having providing a longer longevity to the females (59.1 days). The highest rates of mortality were obtained when they were reared on the cocoa substrate, regardless of the host plant from which they were originally collected, and when kept on citrus, for insects collected on coffee plants. P. citri and P. minor have higher preference for coffee substrate regardless of the original host, thus showing partial host specificity.

Cobertura da pulverização e maturação de frutos do cafeeiro com ethephon em diferentes condições operacionais

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evidence that the Ceratobasidium-like white-thread blight and black rot fungal pathogens from persimmon and tea crops in the Brazilian Atlantic Forest agroecosystem are two distinct phylospecies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The activity of amino acids produced by Paenibacillus macerans and from commercial sources against the root-knot nematode Meloidogyne exigua

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relationships among Pratylenchus jaehni and P. coffeae populations from Brazil.

Wilcken, S.R.S., E.S. Mori, M. Bacci, L.C.C.B. Ferraz, C.M.G. Oliveira & M.M. Inomoto. 2008. Relationships among Pratylenchus jaehni and P. coffeae populations from Brazil. The relationships among Pratylenchus jaehni (C) and six amphimitic Pratylenchus populations from Brazil (three from banana, PcB1, PcB2, and PcB3; one from Aglaonema sp., M2; one from coffee, K5; and one from citrus, C) were studied through morphological and molecular analysis, and pathogenicity test. The analysis of morphometric characteristics of PcB1, M2, C2 and K5, compared with P. jaehni and P. coffeae (K6) data obtained from literature, delineated three groups: P. coffeae (K6), PcB1 and M2; P. jaehni (C1) and C2; and K5. RAPD analysis of PcB1, PcB2, PcB3, M2, C2, K5 and P.jaehni (C1) demonstrated that these populations form three distinct genetic groups: PcB1, PcB2, PcB3 and M2; P.jaehni and C2; and K5. In pathogenicity test, K5 reproduced well on coffee and caused extensive root necrosis, but C2 did not. Population C2 reproduced well on Rangpur lime, which was previously rated as poor host to K5. Therefore, the results demonstrated that C2 is P. jaehni, K5 is an undescribed species of Pratylenchus, and PcB1, PcB2 and PcB3 are P. coffeae. The taxonomic status of M2 remains inconclusive.

Utilização de água residuária do processo pós-colheita do café na produção de mudas de cafeeiro

Intending to achieve better results on coffee production, the coffee producers began, since the 80s, to process the coffee postharvest, in order to ensure product's superior quality. However, with the processing, other problem appeared, the contamination of rivers, creeks, soil and water table from coffee wastewater (ARC). This paper had as main objective to use the ARC on the coffee plants' production verifying its viability and if the ARC is able to supply the coffee potassium requirements when they don't receive potassium chloride in the organic compound. The work was developed at Faculdade de Ciências Agronômicas - UNESP, Botucatu-SP, in a greenhouse located at Departamento de Engenharia Rural. The work consisted of 10 treatments on a 5×2 factorial (5 wastewater proportions of coffee after the harvest processing - 0%, 25%, 50%, 75% and 100% - and potassium chloride presence or absence in the composition), with 4 repetitions with a completely randomized statistical design. The ARC was applied each 48 hours in an irrigation depth of 10 mm. After 6 months, the plants' vegetative characteristic had been evaluated as well the chemical characteristics of the compound and of the plants. We observed that the treatments with potassium chloride presence showed worse vegetative characteristics compared with treatments which did not have KCl in its composition. Moreover, with the increase of the wastewater dosage, it happened a decrease in the vegetative characteristics, however an addition in the chemical characteristics of the compound. Also, the treatments without KCl presence and with 0% and 25% of coffee wastewater had been statistically equal, showing the viability in the use of the ARC in the production of coffee plants, since the compound does not contain KCl and that the water used in the composition is a mixture of 25% of ARC with 75% of common water.

Ácaro da mancha-anular do cafeeiro: controle em função da cobertura pela calda com ramais e volumes de aplicação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização de água residuária do processo pós-colheita do café na produção de mudas de cafeeiro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação de um pulverizador de volume ultra baixo na cultura do café para o controle de Leucoptera coffeella (Lepidoptera: Lyonetiidae)

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Sensibilidade de Lecanicillium lecanii, agente de biocontrole de Hemileia vastatrix, à radiação ultravioleta-B

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização patogênica, morfológica, fisiológica, molecular e sensibilidade a fungicida de Cercospora coffeicola

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)