This study examines the socio-economic impact of fair trade on black emerging citrus fruit farmers in the Eastern Cape Province of South Africa. It is a comparative analysis of farmers involved in fair trade and those who are not. Farmers from Riverside Enterprise and Sundays River Citrus Cooperative were examined to evaluate the impact of fair trade. Such impact was analyzed through looking at access farmers have to foreign markets and their ability to receive high income returns from these markets. The study also discusses the influence fair trade has on the social and economic development of the farmers’ communities. The findings of the study indicate how most fair trade communities have benefited financially and through public infrastructure such as crèches, learning centers and access to computers for both farmers and workers. Such public developments are funded through the fair trade social dividend which is a premium farmers receive for selling their fruit under fair trade. However, the study findings also indicate the limitations of fair trade; farmers have to incur high costs to become fair trade accredited. The study also examines the commodity value chains (hereinafter referred to as CVC) for citrus fair trade farmers and non fair trade farmers. This analysis reveals the procedure of value chains, their benefits and constraints.

Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Green mould is a major citrus postharvest disease caused by a wound pathogen called Penicillium digitatum. Imazalil (IMZ) is the most important postharvest fungicide that is currently registered against green mould and blue mould, given its good protective and curative control and sporulation inhibition. Imazalil can be applied in drench, dip, spray and wax coating applications. Wax coatings improve the quality of the fruit during shelf life by limiting moisture loss and providing a shiny appearance. The primary objective of this study was to investigate the application of imazalil in wax coatings in citrus packhouses to control green mould and preserve fruit quality. The first aim of this study was to evaluate the protective and curative control and sporulation inhibition of IMZ sensitive and resistant isolates of P. digitatum following single IMZ application in wax coating and IMZ application in aqueous dip as well as wax coating. For single application, Valencia orange fruit was curatively or protectively treated with a carnauba-based coating into which IMZ at 3000 μg.mL-1 was mixed. For curative treatments, fruit was treated after 24 hour's incubation. Coating was applied at 0.6, 1.2 and 1.8 L.ton-1 of fruit on a commercial coating applicator. Untreated control and fruit treated with coating only showed up to 80% infection for both sensitive and resistant isolates. Imazalil in coating proved to have better protective than curative action against the sensitive isolate, while control of the resistant isolate was poor. Imazalil residue levels increased with increasing coating load (0.85 to 1.75 μg.g-1). For double application, clementine, satsuma, navel and Valencia orange fruit were used. Curative and protective control following dip only treatment (IMZ sulphate at 500 μg.mL-1 for 45 s and 90 s) was compared with coating only treatment (IMZ at 3000 μg.mL-1 at 1.8 L.ton-1), and double application comprising dip (45 s in IMZ sulphate at 500 μg.mL-1) followed by 2000 μg.mL-1 IMZ in coating at 0.6, 1.2 and 1.8 L.ton-1. Double application resulted in improved residue loading (0.85 to 2.06 μg.g-1) compared to dip only treatments (≈ 0.49 μg.g-1). Coating only resulted in the highest residue levels (1.82 to 7.09 μg.g-1), often exceeding the maximum residue limit of 5 μg.g-1. In all treatments, poor curative and protective control of the resistant isolate (<46% and <55%, respectively) and generally no sporulation inhibition was observed. For the sensitive isolate, dip only treatments resulted in better curative control (≈ 77%) than protective control (≈ 38%). Double application showed increased protective control with increasing wax load (≈ 69%) as well as good curative control (≈ 83%). Wax coating only treatment resulted in poor curative control (≈ 26%), but good protective control (≈ 80%). Sporulation inhibition of the sensitive isolate was generally improved in treatments that included IMZ application in the wax coating. This study successfully showed the additive benefits of double application of IMZ in the wax coating following an aqueous dip application. However, despite improved control of the sensitive isolate, the resistant isolate could not be controlled. The second objective of the study was to evaluate green mould control and quality preservation following IMZ application using different coating and brush types. The inoculation and treatment procedure was similar to the single application of wax coating described above but only the sensitive isolate of P. digitatum was used. Carnauba- or polyethylene-based wax coatings, including IMZ at 3000 μg.mL-1, was applied at a dosage of 0.6, 1.2 and 1.8 L.ton-1 using commercial horsehair or synthetic brushes. Fruit was either incubated for 4 days prior to wound infection ratings or stored at -0.5oC for 26 days and 7 days shelf life. Imazalil residues on fruit increased with increasing coating loads on navel oranges (1.31 to 3.32 μg.g-1) and Valencia oranges (3.22 to 6.00 μg.g-1). Better protective (≈ 58%) than curative control (≈ 14%) was observed, with horsehair brushes resulting in lower sporulation levels (≈ 59%) than synthetic brushes (≈ 64%). Fruit weight loss and firmness loss ratios relative to uncoated control fruit were significantly higher in fruit treated with polyethylene coating compared with carnauba coating treated fruit. However, polyethylene coating resulted in shinier fruit before and after storage, whereas carnauba coating resulted in lower shine ratios. Gaseous (CO2) exchange ratios remained similar for both coatings, but higher polyethylene coating loads (1.8 L.ton-1) resulted in off-tastes similar to the uncoated control fruit and higher than the ratings for carnauba. Scanning electron micrographs revealed an amorphous crystallised natural wax layer with uncovered stomatal pores on the surface of uncoated fruit. The thickness of the applied coating layer increased with increasing coating load. Coating layers following application with synthetic brushes at 1.2 L.ton-1 appeared to be thicker than when applied using horsehair brushes. This study indicated the effects of brush type on the distribution and polishing of the wax coating on the surface of the fruit and also the importance of cautious application of coating as under or over application may lead to poor results in terms of bio-efficacy, residue loading and fruit quality. / AFRIKAANSE OPSOMMING: Groenskimmel is 'n belangrike sitrus na-oessiekte, veroorsaak deur 'n wondpatogeen, genaamd Penicillium digitatum. Imazalil (IMZ) is die belangrikste na-oesfungisied wat tans teen groenskimmel geregistreer is, gegewe sy goeie beskermende en genesende beheer en sporulasie-inhibisie. Imazalil kan in bad-, doop-, spuit- en wakslaagbehandelings toegedien word. Wakslae behou die kwaliteit van die vrugte gedurende raklewe deur vogverlies te beperk en 'n glansvoorkoms te verskaf. Die primêre doel van hierdie studie was om die toediening van imazalil in wakslaagbehandelings in sitruspakhuise vir groenskimmel en vrugkwaliteit beheer te ondersoek. Die eerste doelwit van hierdie studie was om die beskermende en genesende beheer en sporulasie-inhibisie van IMZ sensitiewe en weerstandbiedende isolate van P. digitatum, gevolg deur enkel IMZ toediening in 'n wakslaagbehandeling, en IMZ toediening in 'n doop-, asook wakslaagbehandeling, te evalueer. Vir enkelltoediening is Valencia lemoenvrugte genesend of beskermend met 'n carnauba-gebaseerde wakslaag behandel, waarin IMZ teen 3000 μg.mL-1 gemeng is. Vir genesende behandelings is vrugte ná 24 uur inkubasie behandel. Wakslaagbehandeling is teen 0.6, 1.2 en 1.8 L.ton-1 vrugte op 'n semi-kommersiële paklyn toegedien. Onbehandelde kontrole en vrugte met waks behandel, het slegs tot 80% infeksie vir beide sensitiewe en weerstandbiedende isolate getoon. Imazalil in waks het beter beskermende as genesende aksie teen die sensitiewe isolaat getoon, terwyl beheer van die weerstandbiedende isolaat swak was. Imazalil residuvlakke het met toename in wakslading toegeneem (0.85 tot 1.75 μg.g-1). Vir dubbeltoediening is clementine, satsuma, navel en Valencia lemoenvrugte gebruik. Genesende en beskermende beheer van IMZ na enkel doopbehandeling (IMZ sulfaat teen 500 μg.mL-1 vir 45 s en 90 s), is met enkel waksbehandeling (IMZ teen 3000 μg.mL-1 teen 1.8 L.ton-1) vergelyk, asook dubbeltoediening bestaande uit doop (45 s in IMZ sulfaat teen 500 μg.mL-1), gevolg deur 2000 μg.mL-1 IMZ in waksbehandeling teen 0.6, 1.2 en 1.8 L.ton-1. Dubbeltoediening het verbeterde residulading (0.85 tot 2.06 μg.g-1) tot gevolg gehad, in vergelyking met enkel doopbehandelings (≈ 0.49 μg.g-1). Enkel waksbehandeling het die hoogste residuvlakke (1.82 tot 7.09 μg.g-1) tot gevolg gehad, wat dikwels die maksimum residu-limiet van 5 μg.g-1 oorskry het. In alle behandelings is swak genesende en beskermende beheer van die weerstandbiedende isolaat (<46% en <55%, onderskeidelik), en oor die algemeen, geen sporulasie-inhibisie, waargeneem. Vir die sensitiewe isolaat, het die enkel doopbehandelings beter genesende beheer (≈ 77%) in vergelyking met die beskermende beheer (≈ 38%) tot gevolg gehad. Dubbeltoediening het verhoogde beskermende beheer met toenemende wakslading (≈ 69%) getoon, asook goeie genesende beheer (≈ 83%). Enkel wakslaagbehandeling het swak genesende beheer (≈ 26%) tot gevolg gehad, maar goeie beskermende beheer (≈ 80%). Sporulasie-inhibisie van die sensitiewe isolaat was oor die algemeen beter in behandelings wat IMZ toediening in die wakslaag ingesluit het. Hierdie studie het suksesvol die toegevoegde voordele van dubbeltoediening van IMZ in doopbehandeling en wakslaag getoon. Ten spyte van die verbeterde beheer van die sensitiewe isolaat, kon die weerstandbiedende isolaat egter nie beheer word nie. Die tweede doelwit was om groenskimmelbeheer en behoud van kwaliteit te evalueer, volgende op IMZ toediening deur gebruik van verskillende waks- en borseltipes. Inokulasie- en behandelingsprosedure was soortgelyk aan die enkeltoediening van wakslaagbehandeling soos bo beskryf, maar slegs die sensitiewe isolaat van P. digitatum is gebruik. Carnauba- of poli-etileen-gebaseerde wakslae, insluitende IMZ teen 3000 μg.mL-1, is teen 'n dosis van 0.6, 1.2 en 1.8 L.ton-1 toegedien, deur die gebruik van kommersiële perdehaar of sintetiese borsels. Vrugte is óf vir 4 dae vóór wond-infeksie evaluering geïnkubeer, óf teen -0.5oC vir 26 dae en 7 dae raklewe gestoor. Imazalil residuvlakke op vrugte het met toenemende waksladings op navellemoene (1.31 tot 3.32 μg.g-1) en Valencia lemoene (3.22 tot 6.00 μg.g-1) toegeneem. Beter beskermende (≈ 58%) as genesende beheer (≈ 14%) is waargeneem, met perdehaar borsels wat laer sporulasievlakke (≈ 59%) tot gevolg gehad het, in vergelyking met sintetiese borsels (≈ 64%). Vruggewig- en fermheidsverlies verhoudings, relatief tot onbedekte kontrole vrugte, was betekenisvol hoër in vrugte wat met 'n poli-etileenwaks behandel is, in vergelyking met carnauba-waks behandelde vrugte. Poli-etileen waksbehandeling het egter blinker vrugte vóór en ná opberging tot gevolg gehad, terwyl canauba waksbehandeling laer blink verhoudings tot gevolg gehad het. Gas (CO2) uitruilverhoudings het dieselfde vir beide waksbehandelings gebly, maar hoër poli-etileen waksladings (1.8 L.ton-1) het tot afsmake soortgelyk aan die onbedekte kontrole vrugte gelei, en hoër as die evaluerings vir carnauba. Skandeer-elektronmikrograwe het 'n amorfe gekristalliseerde natuurlike wakslaag met onbedekte stomata op die oppervlak van onbedekte vrugte getoon. Die dikte van die toegediende waks het met toename in wakslading toegeneem. Wakslae na toediening met sintetiese borsels teen 1.2 L.ton-1 het dikker vertoon in vergelyking met perdehaar borsels. Hierdie studie het die effekte van borseltipe op die verspreiding en polering van die wakslaag op die oppervlak van vrugte getoon, en versigtige toediening van wakslae onderskryf, aangesien ónder- of óórtoediening swak resultate, in terme van bio-effektiwiteit, residu-lading en vrugkwaliteit, tot gevolg kan hê. / National Research Foundation, THRIP, Citrus Academy & Citrus Research International for bursary and research funding.

Este trabalho apresenta um mapeamento sobre a evolução da exploração das tradicionais atividades agrícolas no estado de São Paulo, representadas pela cana-de-açúcar, café e citros, a partir das variáveis produção, área, produtividade e número de empregos formais nestas atividades entre 1997 e 2006. Assim, a questão principal foi identificar o padrão da evolução destas variáveis nos municípios. Através de dados secundários, obtidos de órgãos governamentais foram gerados grupos de municípios por meio da análise de cluster, de acordo com as similaridades na produção, área, produtividade e emprego formal. Como subsídio a este trabalho foi discutido o cenário sobre a situação do Agronegócio brasileiro, com destaque o cenário paulista, envolvendo a cana-de-açúcar, café e citros. Os resultados obtidos permitiram identificar grupos de municípios com os maiores crescimentos em determinadas variáveis, sobretudo a grande expansão da produção de cana-de-açúcar, alavancada pelo aumento da área e produtividade, o aumento da produção de café, via elevação de produtividade e o grande aumento do emprego formal na citricultura. / This work show a mapping about the evolution of the exploration of traditional activities in Sao Paulo state, represented by sugar-cane, coffee and citrus fruits, using the variables production, area, productivity and the number of formal employees in these activities between 1997 and 2006. So, the main issue was to identify the pattern of evolution of these variables in the municipalities. Through secondary data, obtained from government institutions groups of counties were generated through the analysis of clusters according to similarities in production, area, productivity and the number of employees. Subsidiary was debated the scenery of the situation of Brazilian Agribusiness, with focus in the State of Sao Paulo and mainly involving sugar cane, coffee and citrus fruit. The results have identified groups of counties with the largest increases in certain variables, especially the great expansion of production of sugar cane, leveraged by the increase in area and productivity, increase the production of coffee, by increased productivity and large increase in formal employment in citrus cultivation.

Este trabalho apresenta um mapeamento sobre a evolução da exploração das tradicionais atividades agrícolas no estado de São Paulo, representadas pela cana-de-açúcar, café e citros, a partir das variáveis produção, área, produtividade e número de empregos formais nestas atividades entre 1997 e 2006. Assim, a questão principal foi identificar o padrão da evolução destas variáveis nos municípios. Através de dados secundários, obtidos de órgãos governamentais foram gerados grupos de municípios por meio da análise de cluster, de acordo com as similaridades na produção, área, produtividade e emprego formal. Como subsídio a este trabalho foi discutido o cenário sobre a situação do Agronegócio brasileiro, com destaque o cenário paulista, envolvendo a cana-de-açúcar, café e citros. Os resultados obtidos permitiram identificar grupos de municípios com os maiores crescimentos em determinadas variáveis, sobretudo a grande expansão da produção de cana-de-açúcar, alavancada pelo aumento da área e produtividade, o aumento da produção de café, via elevação de produtividade e o grande aumento do emprego formal na citricultura. / This work show a mapping about the evolution of the exploration of traditional activities in Sao Paulo state, represented by sugar-cane, coffee and citrus fruits, using the variables production, area, productivity and the number of formal employees in these activities between 1997 and 2006. So, the main issue was to identify the pattern of evolution of these variables in the municipalities. Through secondary data, obtained from government institutions groups of counties were generated through the analysis of clusters according to similarities in production, area, productivity and the number of employees. Subsidiary was debated the scenery of the situation of Brazilian Agribusiness, with focus in the State of Sao Paulo and mainly involving sugar cane, coffee and citrus fruit. The results have identified groups of counties with the largest increases in certain variables, especially the great expansion of production of sugar cane, leveraged by the increase in area and productivity, increase the production of coffee, by increased productivity and large increase in formal employment in citrus cultivation.

Huanglongbing é a mais destrutiva doença da citricultura mundial. Seu recente relato no Brasil, em 2004, e a detecção de duas espécies bacterianas associadas à doença -Candidatus Liberibacter asiaticus e Candidatus Liberibacter americanus resultaram em poucos estudos do comportamento do Huanglongbing nas condições dos pomares brasileiros. Os objetivos deste trabalho foram (i) comparar a eficiência de infecção por Candidatus Liberibacter asiaticus e Candidatus Liberibacter americanus em plantas cítricas inoculadas por meio de enxertia com as duas espécies bacterianas, separadamente, e mantidas sob diferentes temperaturas, e (ii) comparar o progresso temporal e espacial do Huanglongbing causado por ambas as espécies, a partir da infecção natural por Diaphorina citri, tendo plantas de citros ou Murraya paniculata (murta) como fonte primária de inóculo. Para alcançar o primeiro objetivo, dois experimentos foram conduzidos em câmaras de crescimento com temperatura e fotofase controladas. A incidência da doença foi determinada por Real-Time PCR de amostras foliares. As temperaturas mais amenas foram favoráveis à infecção por Candidatus Liberibacter americanus, enquanto que altas temperaturas não afetaram a infecção de Candidatus Liberibacter asiaticus. A eficiência de infecção para esta última espécie foi favorecida nas temperaturas de 17/22°C e 22/27°C (noturna/diurna, respectivamente). Para cumprir com o segundo objetivo, um experimento foi conduzido com diferentes fontes de inóculo, que corresponderam aos seguintes tratamentos: (i) plantas de laranjeira doce da variedade Natal infectadas por Candidatus Liberibacter asiaticus ou Candidatus Liberibacter americanus, (ii) unicamente plantas de Murraya paniculata infectadas por Candidatus Liberibacter americanus e (iii) unicamente plantas de laranjeira doce da variedade Natal infectadas por Candidatus Liberibacter americanus. Cada tratamento foi aplicado em um compartimento isolado de uma casade- vegetação. O primeiro tratamento foi repetido. Em todos os compartimentos, 156 a 158 plantas de laranjeira doce da variedade Valência foram dispostas ao redor das plantas fonte de inóculo. Psilídeos livres das bactérias foram periodicamente confinados em plantas fonte de inóculo e, posteriormente foram liberados na casa-de-vegetação para livre movimentação e multiplicação. Quando as duas espécies bacterianas estavam presentes nas diferentes plantas cítricas utilizadas como fonte de inóculo, houve maior detecção de Candidatus Liberibacter asiaticus e maior eficiência de aquisição desta espécie bacteriana por psilídeos. Quando somente Candidatus Liberibacter americanus estava presente nas plantas fonte de inóculo, a eficiência de transmissão foi maior quando Murraya paniculata foi utilizada como fonte de inóculo, mostrando que Diaphorina citri pode adquirir naturalmente Candidatus Liberibacter 12 americanus de Murraya paniculata e transmiti-la para plantas cítricas. A eficiência de aquisição da espécie Candidatus Liberibacter americanus também foi maior tendo Murraya paniculata como planta fonte de inóculo e não citros. / Huanglongbing is the most destructive disease of citrus worldwide. There are few studies on the behavior of Huanglongbing in the Brazilian orchards conditions due to the recent report in Brazil, in 2004. Two bacterial species were associated with the disease in Brazil: Candidatus Liberibacter asiaticus and Candidatus Liberibacter americanus. The aims of this work were (i) to compare the efficiency of infection by Candidatus Liberibacter asiaticus and Candidatus Liberibacter americanus in citrus graft-inoculated plants with both bacterial species, separately, and kept under different temperatures, and (ii) to compare the spatio-temporal progress of Huanglongbing caused by both species, naturally transmitted by Diaphorina citri, having infected citrus plants or Murraya paniculata (jasmine orange) as primary inoculum sources. To achieve the first objective, two experiments were carried out in plant growth chambers with controlled temperature and light. Disease incidence in the inoculated plants was determined by Real-Time PCR of the leaf samples. The milder temperatures were favorable to Candidatus Liberibacter americanus infection, while the higher temperatures did not affect the infection by Candidatus Liberibacter asiaticus. The infection by this latter species was favored by temperatures of 17/22ºC and 22/27°C (night/day, respectively). To achieve the second objective, an experiment was carried out with different sources of inoculum, corresponding to the following treatments: (i) Natal sweet orange plants infected by Candidatus Liberibacter asiaticus or Candidatus Liberibacter americanus, (ii) only Murraya paniculata plants infected by Candidatus Liberibacter americanus and (iii) only Natal sweet orange plants infected by Candidatus Liberibacter americanus. Each treatment was applied in an isolated compartment of a screenhouse. The first treatment was repeated. In all of the compartments, from 156 to 158 Valencia sweet orange plants were located around the source of inoculum plants. Psyllids free of the bacteria were periodically confined in source of inoculum plants and, after this period, they were set free, and allowed to the free movement and multiplication inside the screenhouse. When both bacterial species were present in the different citrus plants as source of inoculum, there was higher detection of Candidatus Liberibacter asiaticus than Candidatus Liberibacter americanus and higher acquisition efficiency of the former bacterial species than the later by psyllids. When only Candidatus Liberibacter americanus was present in the source of inoculum plants, the higher transmission efficiency was reached when Murraya paniculata served as source of inoculum, showing that Diaphorina citri can naturally acquire Candidatus Liberibacter americanus from Murraya paniculata and transmit it to citrus plants. The acquisition efficiency of the 14 Candidatus Liberibacter americanus species was higher with Murraya paniculata as source of inoculum than with citrus plants was the source of inoculum.

O Brasil é o maior produtor de laranja do mundo e, embora o cultivo ocorra em todos os estados brasileiros, o Estado de São Paulo é o maior produtor, responsável por 80% da produção nacional. Dentre as doenças que podem limitar a produção dos citros encontra-se a podridão floral do citros (PFC), causada pelo fungo Colletotrichum acutatum J. H. Simmonds. Os sintomas desta doença são caracterizados pela presença de lesões necróticas marrons ou alaranjadas nas pétalas e queda dos frutos recém formados, os cálices e os pedúnculos permanecem retidos nos ramos. Em citros, C. acutatum pode sobreviver aderido à superfície das folhas, na forma de apressório quiescente, por pelo menos um mês. As plantas daninhas podem atuar como hospedeiras alternativas de diversos patógenos, servindo como fontes de inóculo e desempenhando um importante papel na epidemiologia das doenças. O objetivo deste trabalho foi verificar se plantas daninhas, comuns em pomares de citros no Estado de São Paulo, podem servir como fonte de inóculo de C. acutatum para esta cultura. Sete espécies de plantas daninhas foram inoculadas com uma suspensão de conídios de C. acutatum, calibrada a 105 conídios/mL. Após a inoculação, estas foram mantidas em câmara úmida por 36 horas e, em seguida, amostras de todas as plantas foram coletadas e observadas em microscópio óptico para verificar a germinação dos conídios. Trinta, sessenta e noventa dias após as inoculações realizou-se o isolamento de C. acutatum das folhas inoculadas. Para isso, amostras de folhas de cada espécie de planta daninha foram coletadas, desinfestadas superficialmente e transferidas para placas de Petri, onde receberam 70 L de extrato floral de citros sobre o local da inoculação, para estimular a germinação dos apressórios ali presentes. As folhas permaneceram incubadas por 24 horas a 23°C, com fotoperíodo de 12 h. Após esse período, as áreas inoculadas das folhas foram cortadas e transferidas para placas de poliestireno contendo meio de Martin. Após o surgimento das primeiras colônias de C. acutatum, discos de quatro milímetros de diâmetro foram transferidos para meio BDA, para a obtenção de colônias puras. Em seguida foi realizado um teste de patogenicidade em flores de laranja doce de três anos de idade. Os dados de porcentagem de isolamento foram analisados análise de variância e testes não paramétricos. Foram observadas a germinação e a formação de apressórios de C. acutatum na superfície de todas as folhas inoculadas, após 36 horas de câmara úmida. Não houve diferença estatística na sobrevivência de C. acutatum ao longo dos 30, 60 e 90 dias e não foi observado nenhum tipo de sintoma nas folhas inoculadas. C. acutatum foi isolado de todas as plantas daninhas analisadas, embora o tempo de sobrevivência tenha variado em função da espécie de daninha. Todos os isolados obtidos das plantas daninhas apresentaram sintomas típicos de PFC em todas as flores inoculadas. Os resultados obtidos demonstraram que as plantas daninhas avaliadas podem servir como hospedeiras alternativas de C. acutatum, resultando em fonte de inóculo primário e secundário deste patógeno para a cultura do citros. / Brazil is the major orange producer in the world, and although the cropping occurs all over the Brazilian States, the São Paulo State is the major producer, responsible for 80% of the national production. Postbloom fruit drop (PFD), caused by the fungus Colletotrichum acutatum J. H. Simmonds is an important disease that can cause yield reduction. The symptoms of this disease are characterized by the presence of brown or orange necrotic lesions in the petals and the drop of young fruits; the calyces and peduncles remain in the branches after fruit drop. In citrus, C. acutatum can adhered to the surface of the leaves, in the form of quiescent appressoria, for at least one month. The weeds can act as alternative hosts of diverse pathogens, serving as inoculum sources and playing an important role in the disease epidemiology. The purpose of this research was to verify if weeds, commons in citrus orchards in São Paulo State, may serve as inoculum source of C. acutatum for this crop. Seven weed species were inoculated with a conidial suspension of C. acutatum, calibrated with 105 conidia/mL. After the inoculation, the weeds were kept in humidity chamber for 36 hours. Samples of all weeds were collected and observed in optical microscope to verify the conidia germination. Thirty, sixty and ninety days after inoculation, C. acutatum was isolated from the inoculated leaves. For this purpose, leaves of each weed species were collected, superficially disinfested and transferred to Petri dishes. The leaves received 70 L of citrus flower extract over the inoculation area to stimulate the appressoria germination. The leaves were incubated for 24 hours at 23°C, with 12 hours of photoperiod. After this period, the inoculated areas were cut and transferred to polystyrene dishes with Martin medium. After the appearance of the first colonies of C. acutatum, discs of four millimeters of diameter were transferred to PDA medium to obtain pure colonies. A pathogenicity test was carried out in three years old sweet orange flowers. The percentage of pathogen isolation was analyzed by variance analysis or non-parametric analysis. Conidia germination and appressoria formation of C. acutatum in all inoculated leaves were observed, after 36 hours of humidity chamber. There was no statistical difference in the C. acutatum survival during 30, 60 e 90 days and no type of symptom was observed in the inoculated leaves. C. acutatum was isolated from every weed analyzed, although the survival period varied among the weed species. Every isolated obtained from the weeds presented typical PFD symptoms in every inoculated flowers. The results showed that weeds can serve as alternative hosts of C. acutatum, contributing in primary and secondary inoculum source of this pathogen to the citrus crop.

A crise da água, o aumento de esgoto domésticos gerado em estações de tratamentos e o despejo destes efluentes em corpos d\'água vêm sugerindo novas soluções para esses problemas. A disposição de água residuária tratada em solos implica na reciclagem de matéria orgânica e dos nutrientes, atuando como um processo complementar ao tratamento dessas águas. Rica em nutrientes principalmente N (nitrogênio), P (fósforo) e Na (sódio), a água residual tratada vem sendo utilizada na agricultura, utilizando critérios técnicos, como fonte de nutrientes para diversas culturas. Diante deste contexto, o objetivo deste trabalho foi analisar os possíveis efeitos da irrigação com efluente tratado em algumas propriedades químicas e físicas de um solo cultivado com laranja. A área experimental esta situada ao lado da Estação de Tratamento de Esgoto (ETE) do Ribeirão Piracicamirim que se localiza nas margens da rodovia \"Luiz de Queiroz\" no município de Piracicaba-SP. Os tratamentos aplicados foram relacionados ao percentual de umidade da capacidade de campo variando em T100%, T125%, T150%, T200% e TSI (tratamento sem irrigação). O delineamento experimental utilizado foi o de blocos inteiramente casualizados com parcelas subdivididas no tempo, com três repetições. A adubação realizada foi a de metade da dose recomendada para a cultura da laranja. Em todo o estudo as amostragens de solo foram realizadas nas camadas 0-10, 10-20, 20-40, 40-60, 60-80 e 80-100, enquanto que as amostragens de solução do solo foram realizadas nas profundidades 30, 100 e 200 cm. As variáveis químicas determinadas no solo foram: pH, H + Al, Al, Na, K, Ca e Mg. Em solução do solo as variáveis determinadas foram: pH, CE, Al, Na, K, Ca e Mg. As variáveis físicas determinadas foram: fração granulométrica e grau de dispersão de argilas. O efluente de esgoto tratado (EET) utilizado apresenta baixas concentrações de Ca, Mg, Na, K, Al, CE e RAS quando comparado com valores encontrados na literatura. Por esse fato, o EET apresenta menor potencial de alterações nas propriedades químicas e físicas do solo. O teor de sódio trocável e PST aumentaram no decorrer do experimento, enquanto a concentração de sódio na solução do solo diminuiu. O cálcio trocável no solo sofreu diminuição dos teores nas camadas superficiais, e aumento nas camadas subsuperficias. As perspectivas da irrigação de efluente de esgoto tratado na cultura da laranja são promissoras, haja vista a importância da cultura no cenário brasileiro e mundial. No entanto, estudos de longo prazo são necessários a fim de monitorar os possíveis impactos que a irrigação de EET possa ocasionar na estrutura do solo. / The crisis of the water, the sewage domestic increase generated in stations of treatments and the spilling of these effluents in bodies of water are suggesting new solutions for those problems. The disposition of wastewater treated in soils implicate in the nutrient and organic matter recycling, acting as a complementary process to the treatment of those waters. Rich in nutrients mainly N (Nitrogen), P (Phosphorus) and Na (Sodium) the treated wastewater has been used in the agriculture through technical criteria as source of nutrients for several crops. Before this context, the objective of this work was to analyze the possible effects of the irrigation with effluent treated in some chemical and physical properties of a soil cultivated with Orange. The experimental area located her beside the Station of Sewage Treatment (SST) Piracicamirim that is located in the margins of the highway \"Luiz de Queiroz\" in the municipal district of Piracicaba, São Paulo State. The applied treatments were related to the percentile of humidity of the field capacity varying in T100%, T125%, T150%, T200% and TSI (treatment without irrigation). The experimental design was a split plot scheme of randomized blocks subdivided in time, with five treatments and three repetitions. The accomplished fertilization was the one of half of the dose recommends for the orange crop. In whole the study the soil samplings were accomplished in the layers 0-10, 10-20, 20-40, 40-60, 60-80 and 80-100, while the samplings of soil solution were accomplished in the depths 30, 100 and 200 cm. The chemical variables determined in the soil were pH, H + Al, Al, Na, K, Ca and Mg. In soil solution the variables were pH, CE, Al, Na, K, Ca and Mg. The certain physical variables were fraction particle sizing and degree of clay dispersion. The sewage effluent treated (SET) used presents low concentrations of Ca, Mg, In the, K, Al, CE and RAS when compared with values found in the literature. For that fact, SET present potential minor of alterations in the chemical and physical properties of the soil. The exchangeable sodium and PST increased in elapsing of the experiment, while the concentration of sodium in the soil solution decreased. The exchangeable calcium in the soil suffered decrease in the superficial layers, and increase in the subsuperficial layers. The perspectives of the irrigation of SET in the orange crop are promising, have seen the importance of the culture in the Brazilian and world scenery. However, it is suggested studies of long period in order to monitor the possible impacts to cause in the structure of the soil.

Agriculture plays a significant role in South Africa’s export earning and in providing employment opportunities. Amongst the major agricultural crops is citrus. Within the context of postmodern and feminist geographies and utilizing the intensive research design, this thesis discusses citrus production with a focus on growers and black women workers in the Kat River Valley area in Fort Beaufort, Eastern Cape. The thesis also explores the challenges and implications of restructuring within agriculture for growers, cooperatives and labour within the citrus industry. It is argued that whilst legislation related to labour and tenure within agriculture has changed since the mid-1990s, power relations in the citrus industry have remained firmly entrenched. Consequently, the flexible labour strategies that the citrus farmers adopted have had serious consequences for women worker

A crise da água, o aumento de esgoto domésticos gerado em estações de tratamentos e o despejo destes efluentes em corpos d\'água vêm sugerindo novas soluções para esses problemas. A disposição de água residuária tratada em solos implica na reciclagem de matéria orgânica e dos nutrientes, atuando como um processo complementar ao tratamento dessas águas. Rica em nutrientes principalmente N (nitrogênio), P (fósforo) e Na (sódio), a água residual tratada vem sendo utilizada na agricultura, utilizando critérios técnicos, como fonte de nutrientes para diversas culturas. Diante deste contexto, o objetivo deste trabalho foi analisar os possíveis efeitos da irrigação com efluente tratado em algumas propriedades químicas e físicas de um solo cultivado com laranja. A área experimental esta situada ao lado da Estação de Tratamento de Esgoto (ETE) do Ribeirão Piracicamirim que se localiza nas margens da rodovia \"Luiz de Queiroz\" no município de Piracicaba-SP. Os tratamentos aplicados foram relacionados ao percentual de umidade da capacidade de campo variando em T100%, T125%, T150%, T200% e TSI (tratamento sem irrigação). O delineamento experimental utilizado foi o de blocos inteiramente casualizados com parcelas subdivididas no tempo, com três repetições. A adubação realizada foi a de metade da dose recomendada para a cultura da laranja. Em todo o estudo as amostragens de solo foram realizadas nas camadas 0-10, 10-20, 20-40, 40-60, 60-80 e 80-100, enquanto que as amostragens de solução do solo foram realizadas nas profundidades 30, 100 e 200 cm. As variáveis químicas determinadas no solo foram: pH, H + Al, Al, Na, K, Ca e Mg. Em solução do solo as variáveis determinadas foram: pH, CE, Al, Na, K, Ca e Mg. As variáveis físicas determinadas foram: fração granulométrica e grau de dispersão de argilas. O efluente de esgoto tratado (EET) utilizado apresenta baixas concentrações de Ca, Mg, Na, K, Al, CE e RAS quando comparado com valores encontrados na literatura. Por esse fato, o EET apresenta menor potencial de alterações nas propriedades químicas e físicas do solo. O teor de sódio trocável e PST aumentaram no decorrer do experimento, enquanto a concentração de sódio na solução do solo diminuiu. O cálcio trocável no solo sofreu diminuição dos teores nas camadas superficiais, e aumento nas camadas subsuperficias. As perspectivas da irrigação de efluente de esgoto tratado na cultura da laranja são promissoras, haja vista a importância da cultura no cenário brasileiro e mundial. No entanto, estudos de longo prazo são necessários a fim de monitorar os possíveis impactos que a irrigação de EET possa ocasionar na estrutura do solo. / The crisis of the water, the sewage domestic increase generated in stations of treatments and the spilling of these effluents in bodies of water are suggesting new solutions for those problems. The disposition of wastewater treated in soils implicate in the nutrient and organic matter recycling, acting as a complementary process to the treatment of those waters. Rich in nutrients mainly N (Nitrogen), P (Phosphorus) and Na (Sodium) the treated wastewater has been used in the agriculture through technical criteria as source of nutrients for several crops. Before this context, the objective of this work was to analyze the possible effects of the irrigation with effluent treated in some chemical and physical properties of a soil cultivated with Orange. The experimental area located her beside the Station of Sewage Treatment (SST) Piracicamirim that is located in the margins of the highway \"Luiz de Queiroz\" in the municipal district of Piracicaba, São Paulo State. The applied treatments were related to the percentile of humidity of the field capacity varying in T100%, T125%, T150%, T200% and TSI (treatment without irrigation). The experimental design was a split plot scheme of randomized blocks subdivided in time, with five treatments and three repetitions. The accomplished fertilization was the one of half of the dose recommends for the orange crop. In whole the study the soil samplings were accomplished in the layers 0-10, 10-20, 20-40, 40-60, 60-80 and 80-100, while the samplings of soil solution were accomplished in the depths 30, 100 and 200 cm. The chemical variables determined in the soil were pH, H + Al, Al, Na, K, Ca and Mg. In soil solution the variables were pH, CE, Al, Na, K, Ca and Mg. The certain physical variables were fraction particle sizing and degree of clay dispersion. The sewage effluent treated (SET) used presents low concentrations of Ca, Mg, In the, K, Al, CE and RAS when compared with values found in the literature. For that fact, SET present potential minor of alterations in the chemical and physical properties of the soil. The exchangeable sodium and PST increased in elapsing of the experiment, while the concentration of sodium in the soil solution decreased. The exchangeable calcium in the soil suffered decrease in the superficial layers, and increase in the subsuperficial layers. The perspectives of the irrigation of SET in the orange crop are promising, have seen the importance of the culture in the Brazilian and world scenery. However, it is suggested studies of long period in order to monitor the possible impacts to cause in the structure of the soil.

Orientador: Roberto Testezlaf / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-15T11:30:19Z (GMT). No. of bitstreams: 1 Salvador_ConanAyade_M.pdf: 2153491 bytes, checksum: 07c1fb1dc7e368cb888cc1341cf07208 (MD5) Previous issue date: 2010 / Resumo: O manejo hídrico-nutricional das plântulas na produção de porta-enxertos de mudas cítricas na fase sementeira, realizado por sistemas de aspersão operados manualmente, apresenta o problema ambiental do descarte da água ou solução residual proveniente da fertirrigação. O rejeito hídrico do sistema de produção tem como destino o próprio solo e pode, desta forma, atingir lençóis freáticos e contaminar os recursos hídricos da bacia hidrográfica onde está localizada a propriedade. Buscando uma solução para essa problemática, o presente projeto teve como objetivo desenvolver um equipamento de irrigação que aplique água por capilaridade para ser empregado na produção de porta-enxertos de mudas cítricas, na fase de sementeira e que possibilitasse o uso racional dos recursos hídricos nesse setor. Inicialmente, realizou-se um diagnóstico das características tecnológicas da irrigação utilizada pelos viveiristas, por meio do preenchimento de um questionário. Em uma segunda etapa do trabalho, avaliou-se o desempenho da irrigação empregada pelos produtores de mudas, estimando a eficiência da irrigação e as perdas de água e de sais, utilizando uma metodologia desenvolvida especificamente para esse objetivo. Com os resultados das etapas anteriores, foram desenvolvidas propostas de equipamentos, seguido da construção de protótipos e testes preliminares. Executou-se a caracterização hidráulica do protótipo escolhido, com e sem a presença de tubetes preenchidos com substratos, com a determinação das curvas características de vazão versus pressão para três pressões de serviço (10 kPa, 15 kPa e 20 kPa) e estimando-se o tempo e volume de enchimento. Monitorou-se, nos ensaios com substrato, a subsidência e perda de substrato e o armazenamento de água, entre as quatro aplicações de água. Por fim, realizou-se a simulação da operação deste equipamento em campo. Os resultados da pesquisa confirmaram que o produtor de porta-enxertos de mudas cítricas característico do estado de São Paulo, no ano de 2007, tinha uma área de produção entre 1001 m2 a 3000 m2; produzia até 80.000 mudas anualmente; utilizava casca de pinus como substratos; empregava chuveiros ou tubos perfurados como sistemas de irrigação juntamente com fertirrigação, não utilizando técnicas para o manejo da irrigação. As avaliações de desempenho da irrigação na produção de porta-enxerto de mudas cítricas na fase de sementeira confirmaram que esta atividade é realizada sem controle efetivo da lâmina aplicada gerando baixas eficiências de irrigação, com perdas significativas de água e fertilizantes. O equipamento desenvolvido demonstrou potencialidades no aprimoramento do manejo e na automação do processo, se mostrando uma alternativa tecnológica viável para esse sistema de produção / Abstract: The water and nutrition management in the production of citrus rootstocks in the seedling phase performed by sprinkler systems, manually operated, presents the environmental outcome of water or residual solution disposal from the fertigation. The generated wastewater is generally discarded directly in the soil with the risk to reach the groundwater and contaminate the watershed water resources where the property is located. Looking for a feasible technical alternative to solving this problem, this research aimed to develop an irrigation system that applied water by capillary action to be employed in the production of citrus rootstocks in the seedling stage that would allow the appropriate water resources use in this sector. Initially, it was carried on the assessment of the characteristics of irrigation used by citrus nurseries growers by fill in a feedback form. In the second stage of the study it was evaluated the irrigation system performance used by producers, estimating the efficiency of irrigation and water and salt losses, using a field methodology developed specifically for this purpose. With the results of the previous steps, it was developed and design equipment proposals, followed by construction of prototypes with preliminary testing. Afterwards, the chosen prototype was hydraulically characterized with the determination of the flow rate and pressure relationship for three operating pressures (10 kPa, 15 kPa and 20 kPa), estimating the time and filling volume of the equipment. The substrate subsidence and material loss were monitored during the hydraulic trails, estimating the substrate water storage in the four water applications. Finally, a field simulation of the equipment was performed to compare with the conventional irrigation. The survey results confirmed that the producer of citrus rootstocks characteristic of the state of Sao Paulo in 2007, had a production area from 1001 m2 to 3000 m2, producing up to 80,000 seedlings annually, used pine husk as substrates; employed showers or perforated pipes and irrigation with fertigation, not using techniques for irrigation. Performance appraisals of irrigation in the production of citrus rootstocks in the seedlings stage confirmed that the irrigation activity in the citrus rootstock production during the seedling phase is performed without effective control of the applied depth, generating low irrigation efficiencies with significant losses of water and fertilizers. The developed capillarity equipment, despite showing a low performance, has shown potential to improve the management and automation of the process, proving to be a viable alternative technology for this production system / Mestrado / Agua e Solo / Mestre em Engenharia Agrícola