Thesis (MScAgric)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The export of South African fruit to some of its biggest international markets may be rejected if the phytosanitary pest, Phlyctinus callosus (Coleoptera: Curculionidae) is found in fruit consignments. An alternative to methyl bromide fumigation is needed and one of the most promising of the alternative treatments is phytosanitary irradiation as it is environmentally friendly, does not leave residues on food or in the environment and it is effective against a wide variety of insects. Field-collected weevils were treated with five doses of gamma irradiation (5, 10, 20, 40 and 80 Gy) and the fecundity and fertility of mating crosses of treated males and females with treated and untreated individuals of the opposite sex, were determined to evaluate the effect on P. callosus reproductive ability post-treatment. Results indicated that irradiation treatment did not affect fecundity, but fertility was significantly affected, decreasing as the irradiation dose increased. Females were more susceptible to the irradiation treatment than males, and after treatment with 80 Gy, eggs laid by females and mated with either treated or untreated males, did not hatch. A generic dose of 400 Gy for all insect pests except tephritid fruit flies and pupae and adult Lepidoptera is currently approved by USDA-APHIS (United States Department of Agriculture – Animal and Plant Health Inspection Services) for use on certain commodities. Results from the present study support the development of a species-specific dose for P. callosus, as well as the development of a group generic dose for the Curculionidae that is lower than 400 Gy. Effective phytosanitary irradiation treatments are only feasible if the treatment does not adversely affect fruit quality and the marketability of export fruit. Therefore, an investigation of the effects of irradiation disinfestations treatments on the quality of the new pluot cultivar, ‘Flavor Fall’ was made. Packed cartons were treated with three doses of gamma irradiation: 400 Gy, 900 Gy and 1400 Gy. After treatment fruit underwent a PD 7 dual temperature cold storage regime for 42 days and a shelf-life simulation for 7 days. The impact of insect-proof bags, sometimes required by importing countries to keep insects off packaged fruit, was also investigated. Respiration rate of the fruit was measured throughout and fruit quality evaluations were done after cold storage and after shelf-life. The results indicated that quality parameters measured at the end of cold storage, which would be after the fruit arrives at the export markets, were above the minimum standards for overseas markets. Gel breakdown was unacceptably high after the higher temperature exposure of shelf-life for fruit treated with the 900 and 1400 Gy doses. The insect-proof bags reduced shrivel, but resulted in higher incidence of gel breakdown. The use of irradiation, together with the use of the insect-proof bag, has potential as an alternative postharvest mitigation treatment for plums. Lastly, an investigation into potential rearing methods for P. callosus, including recommendation for the future, was made as the availability of a sustainable rearing method that ensures a consistent supply of high quality P. callosus adults would enable continuous research with greater numbers of this pest. The information generated in this study provides a greater understanding of the radiation biology of, not only this curculionid species, but the Curculionidae as a group, and is valuable in advancing the development of alternative postharvest control measures against this phytosanitary pest. / AFRIKAANSE OPSOMMING: Suid Afrikaanse vrugte uitvoere na van die grootste internasionale markte mag weg gewys word as die fitosanitêre pes, Phlyctinus callosus (Coleoptera: Curculionidae) in die versending gevind word. ‘n Alternatief vir metiel bromied beroking word benodig en een van die mees belowende alternatiewe behandelings is fitosanitêre bestraling aangesien dit omgewings vriendelik is, nie residue op kos of in die omgewing los nie, en effektief is teen ‘n wye verskeidenheid van insekte. Veldversamelde kalanders is behandel met vyf dosisse gamma bestraling (5, 10, 20, 40 en 80 Gy) waarna die vrugbaarheid van paringskruisings bepaal is deur kruisings tussen behandelde manlike en vroulike kalanders met behandelde en nie-behandelde individue van die teenoorgestelde geslag te maak, en so die na-behandelings effek op die voortplantings vermoeë van P. callosus te evalueer. Die resultate het getoon dat die bestralings behandeling geen invloed gehad het op die hoeveelheid eiers wat gelê is nie, maar dat die uitbroei van eiers aanduidend geaffekteer is deur die behandeling. Die hoeveelheid eiers wat uitgebroei het, het minder geraak soos die bestralings behandeling toegeneem het. Vroulike kalanders was meer sensitief vir die behandeling en na 80 Gy, of hul gekruis is met behandelde of niebehandelde mannetjies, het geen eiers uitgebroei nie. ‘n Generiese dosis van 400 Gy vir alle insekte, uitsluitend tephritiese vrugte vlieë en papies en volwasse Lepidoptera is huidiglik goedgekeur deur die USDA-APHIS (United States Department of Agriculture – Animal and Plant Health Inspection Services) vir sekere kommoditeite. Die resultate van die huidige studie ondersteun die ontwikkeling van ‘n spesie-spesifieke dosis vir P. callosus, so ook die ontwikkeling van ‘n generiese groep dosis vir Curculionidae wat laer as 400 Gy is. Effektiewe fitosanitêre bestralings behandeling is slegs moontlik indien die behandelings dosis nie nadelig vir vrugkwaliteit en die bemarking van uitvoer vrugte is nie. Dus is die effek wat bestralings bestryding behandeling op die kwaliteit van ‘n nuwe pluot kultivar, ‘Flavor Fall’ ondersoek. Vrugte verpak in kartonne is met drie dosisse gamma bestraling behandel: 400 Gy, 900 Gy en 1400 Gy. Na behandeling is die vrugte deur ‘n PD 7 dubbel temperatuur koelopbergings regime van 42 dae en rak-lewe simulasie vir 7 dae gesit. Die impak van insek-bestande sakke wat insekte van die verpakte vrugte weg hou en soms deur invoerende lande ‘n vereiste is, is ook ondersoek. Respirasie tempo van die vrugte is getoets en vrugkwaliteit evaluasies is gedoen na koelopberging en rak-lewe. Die resultate het getoon dat die kwaliteits maatstawwe wat getoets is na koelopberging (wat tipies is wanneer die vrugte by die uitvoer mark arriveer), almal bo die minimum standaarde van die uitvoer markte was. Gel-afbraak was onaanvaarbaar hoog na blootstelling aan die hoër temperature tydens rak-lewe vir vrugte wat behandel is met 900 en 1400 Gy. Die insek-bestande sakke het verrimpeling verminder, maar die voorkoms van gel-afbraak vermeerder. Die gebruik van bestraling, tesame met die insek-bestande sakke, het potensiaal as alternatiewe na-oes behandeling vir pruime. Laastens is ‘n ondersoek ingestel vir moontlike teeltegnieke vir P. callosus en aanbevelings gemaak vir toekomstike studies. Die beskikbaarheid van ‘n volhoubare teeltegniek wat konstante, hoë kwaliteit P. colossus individue verskaf sal aaneenlopende navorsing met groter getalle van die pes moontlik maak. Die inligting wat deur hierdie studie gegenereer is help om die bestralings biologie, nie net van hierdie curculionid spesie nie, maar die Curculionidae as ‘n groep te verstaan, en is kosbaar in die bevordering van ontwikkeling van alternatiewe na-oes beheer meganismes teen hierdie fitosanitêre pes.

Esse trabalho teve dois objetivos distintos, quantificar e caracterizar os danos pós-colheita em frutos de ameixa e nectarina na Companhia de Entrepostos e Armazéns Gerais de São Paulo (CEAGESP) e testar produtos que possam ser utilizados no controle das doenças pós-colheita podridão parda (Monilinia fructicola) e podridão mole (Rhizopus stolonifer) nestes dois frutos. Durante a safra 2003 e 2004, foram realizados 20 levantamentos de quantificação de danos em frutos de nectarina e 11 em frutos de ameixa. Em cada levantamento foram avaliados 1% do total de caixas comercializados em cinco permissionários da CEAGESP. A amostragem foi estratificada por variedade, calibre e procedência dos frutos, sendo quantificados danos mecânicos, fisiológicos e doenças pós-colheita. Para o controle da podridão parda e mole, o efeito curativo e protetor do CaCl2, cera e luz UV-C, em diferentes concentrações e o efeito curativo do tratamento com ozônio foram avaliados. A incidência de danos na CEAGESP em frutos de ameixa variou de 5 a 47%, e em nectarina entre 14 e 54%, considerando as safras 2003 e 2004. Tanto em ameixa como em nectarina os danos mais freqüentes foram os mecânicos, com variação de 2 a 25% em frutos de ameixa e de 7 a 30% em frutos de nectarina. Danos fisiológicos variaram de 1 a 22% e de 2 a 18% em frutos de ameixa e nectarina, respectivamente. Danos provocados por doenças variaram de 0 a 13% em frutos de ameixa e de 1 a 9% em frutos de nectarina. Entre os patógenos mais constatados figuraram fungos do gênero Rhizopus, Monilinia, Geotrichum, Cladosporium, Fusarium e Alternaria, além de bactérias. Correlação entre a incidência de frutos com dano mecânico e a incidência de frutos doentes foi constatada na safra 2004, nos dois frutos. Em ameixa, a variedade Gulfblazer apresentou maior incidência a danos mecânicos e fisiológicos. Não foi observada diferença na incidência de danos mecânicos e de doenças, entre as variedades de nectarina avaliadas na safra 2003. Na safra 2004, a incidência de danos mecânicos e fisiológicos foi superior na variedade Sunraycer comparada às demais variedades. Em relação aos produtos testados, no geral, CaCl2 a 1%, mostrou potencial de controle das duas doenças nos dois frutos, aplicado como protetor ou curativo. A cera ECF 124 a base de carnaúba foi o produto mais eficiente, com redução de até 70% das duas doenças em ambos os frutos, principalmente quando aplicada de maneira protetora, a 9%. As doses (1,4 e 5,2 kJm-2) de UV-C testadas não controlaram as doenças com resultados praticamente iguais à testemunha (dose 0,0 kJm-2). A presença de ozônio não reduziu nenhuma das doenças em nenhum dos dois frutos avaliados. / This study had two distinct objectives, to quantify and characterize the postharvest damages in plums and nectarines in the wholesale market of São Paulo (CEAGESP), and to test products that can be used in the control of the postharvest diseases such as the brown rot (Monilinia fructicola) and soft rot (Rhizopus stolonifer) in these two fruits species. Twenty assessments in nectarine and eleven in plums were carried out in 2003 and 2004. In each year 1% of the total of boxes commercialized in five outlets of CEAGESP was assessed, considering mechanical and physiological damages and postharvest diseases. The selection of samples was conducted through stratified sampling, taking fruit cultivar, place of origin and fruit size as the stratification criteria. Curative and protective control measures of brown and soft rot were analyzed testing CaCl2, wax and UV-C light, in different concentrations. The ozone was studied only as curative treatment. The incidence of damages in plums at CEAGESP ranged from 5 to 47%, and in nectarines from 14 to 54%. Either in plums or in nectarines, postharvest mechanical injuries were the most frequent damages, varying from 2 to 25% in plums and from 7 to 30% in nectarines. Physiological damages ranged from 1 to 22% and from 2 to 18% in plums and nectarines, respectively. Postharvest diseases ranged from 0 to 13% in plums and from 1 to 9% in nectarines. The most frequent postarvest pathogens were Rhizopus, Monilinia, Geotrichum, Cladosporium, Fusarium and Alternaria, besides bacteria. A correlation between the incidence of mechanical damages and the incidence of postharvest diseases in 2004 in both fruits was noticed. Cultivar Gulfblazer (plum) showed more incidence of mechanical and physiological damages than Reubennel. No differences were observed in the incidence of mechanical and physiological damages among the cultivars of nectarines assessed in 2003. No difference in the susceptibility to postharvest diseases among the nectarine cultivars Sunred, Sunripe, Sunraycer and Colombina in 2003 was verified. In 2004 cv. Sunraycer showed incidence of mechanical damages significantly higher than the other varieties. Regarding the products tested, as a whole, CaCl2 at 1% showed potential of controlling the two diseases in both kind of fruits, applied as a protective or curative measure. The carnauba wax (ECF 124) was the most efficient product, with a reduction of up to 70% of both diseases in both kind of fruits, mainly when applied as a protective agent, at 9%. The doses (1,4 e 5,2 kJm-2) of UV-C tested did not control the diseases with results practically similar to the reference dose (0,0 kJm-2). The presence of ozone did not reduce either of the diseases in any of the fruits evaluated.

Esse trabalho teve dois objetivos distintos, quantificar e caracterizar os danos pós-colheita em frutos de ameixa e nectarina na Companhia de Entrepostos e Armazéns Gerais de São Paulo (CEAGESP) e testar produtos que possam ser utilizados no controle das doenças pós-colheita podridão parda (Monilinia fructicola) e podridão mole (Rhizopus stolonifer) nestes dois frutos. Durante a safra 2003 e 2004, foram realizados 20 levantamentos de quantificação de danos em frutos de nectarina e 11 em frutos de ameixa. Em cada levantamento foram avaliados 1% do total de caixas comercializados em cinco permissionários da CEAGESP. A amostragem foi estratificada por variedade, calibre e procedência dos frutos, sendo quantificados danos mecânicos, fisiológicos e doenças pós-colheita. Para o controle da podridão parda e mole, o efeito curativo e protetor do CaCl2, cera e luz UV-C, em diferentes concentrações e o efeito curativo do tratamento com ozônio foram avaliados. A incidência de danos na CEAGESP em frutos de ameixa variou de 5 a 47%, e em nectarina entre 14 e 54%, considerando as safras 2003 e 2004. Tanto em ameixa como em nectarina os danos mais freqüentes foram os mecânicos, com variação de 2 a 25% em frutos de ameixa e de 7 a 30% em frutos de nectarina. Danos fisiológicos variaram de 1 a 22% e de 2 a 18% em frutos de ameixa e nectarina, respectivamente. Danos provocados por doenças variaram de 0 a 13% em frutos de ameixa e de 1 a 9% em frutos de nectarina. Entre os patógenos mais constatados figuraram fungos do gênero Rhizopus, Monilinia, Geotrichum, Cladosporium, Fusarium e Alternaria, além de bactérias. Correlação entre a incidência de frutos com dano mecânico e a incidência de frutos doentes foi constatada na safra 2004, nos dois frutos. Em ameixa, a variedade Gulfblazer apresentou maior incidência a danos mecânicos e fisiológicos. Não foi observada diferença na incidência de danos mecânicos e de doenças, entre as variedades de nectarina avaliadas na safra 2003. Na safra 2004, a incidência de danos mecânicos e fisiológicos foi superior na variedade Sunraycer comparada às demais variedades. Em relação aos produtos testados, no geral, CaCl2 a 1%, mostrou potencial de controle das duas doenças nos dois frutos, aplicado como protetor ou curativo. A cera ECF 124 a base de carnaúba foi o produto mais eficiente, com redução de até 70% das duas doenças em ambos os frutos, principalmente quando aplicada de maneira protetora, a 9%. As doses (1,4 e 5,2 kJm-2) de UV-C testadas não controlaram as doenças com resultados praticamente iguais à testemunha (dose 0,0 kJm-2). A presença de ozônio não reduziu nenhuma das doenças em nenhum dos dois frutos avaliados. / This study had two distinct objectives, to quantify and characterize the postharvest damages in plums and nectarines in the wholesale market of São Paulo (CEAGESP), and to test products that can be used in the control of the postharvest diseases such as the brown rot (Monilinia fructicola) and soft rot (Rhizopus stolonifer) in these two fruits species. Twenty assessments in nectarine and eleven in plums were carried out in 2003 and 2004. In each year 1% of the total of boxes commercialized in five outlets of CEAGESP was assessed, considering mechanical and physiological damages and postharvest diseases. The selection of samples was conducted through stratified sampling, taking fruit cultivar, place of origin and fruit size as the stratification criteria. Curative and protective control measures of brown and soft rot were analyzed testing CaCl2, wax and UV-C light, in different concentrations. The ozone was studied only as curative treatment. The incidence of damages in plums at CEAGESP ranged from 5 to 47%, and in nectarines from 14 to 54%. Either in plums or in nectarines, postharvest mechanical injuries were the most frequent damages, varying from 2 to 25% in plums and from 7 to 30% in nectarines. Physiological damages ranged from 1 to 22% and from 2 to 18% in plums and nectarines, respectively. Postharvest diseases ranged from 0 to 13% in plums and from 1 to 9% in nectarines. The most frequent postarvest pathogens were Rhizopus, Monilinia, Geotrichum, Cladosporium, Fusarium and Alternaria, besides bacteria. A correlation between the incidence of mechanical damages and the incidence of postharvest diseases in 2004 in both fruits was noticed. Cultivar Gulfblazer (plum) showed more incidence of mechanical and physiological damages than Reubennel. No differences were observed in the incidence of mechanical and physiological damages among the cultivars of nectarines assessed in 2003. No difference in the susceptibility to postharvest diseases among the nectarine cultivars Sunred, Sunripe, Sunraycer and Colombina in 2003 was verified. In 2004 cv. Sunraycer showed incidence of mechanical damages significantly higher than the other varieties. Regarding the products tested, as a whole, CaCl2 at 1% showed potential of controlling the two diseases in both kind of fruits, applied as a protective or curative measure. The carnauba wax (ECF 124) was the most efficient product, with a reduction of up to 70% of both diseases in both kind of fruits, mainly when applied as a protective agent, at 9%. The doses (1,4 e 5,2 kJm-2) of UV-C tested did not control the diseases with results practically similar to the reference dose (0,0 kJm-2). The presence of ozone did not reduce either of the diseases in any of the fruits evaluated.

As doenças pós-colheita em goiabas podem representar danos entre 20 e 40%, em função de condições ambientais e manejo integrado de doenças tanto antes quanto após a colheita. A adequação dos produtores às normas do Programa Integrado de Frutas (PIF) garante a obtenção de frutos com qualidade, produzidos de forma sustentável. Porém, exige o uso racional de agroquímicos durante as fases de produção da fruta. Neste contexto, utilizando a variedade Kumagai de polpa branca, os objetivos deste trabalho foram: (i) determinar as condições ambientais favoráveis à colonização natural de Guignardia psidii em goiabas; (ii) quantificar a incidência das doenças pós-colheita em goiabas nos dois principais mercados atacadistas do Estado de São Paulo; (iii) detectar e quantificar as doenças quiescentes desde a flor até em frutos no ponto de colheita; (iv) verificar o efeito da atmosfera controlada utilizando altas concentrações de O2 no controle das principais doenças pós-colheita da goiaba. Experimentos em condições controladas foram conduzidos para determinar o efeito de condições ambientais na colonização de G. psidii em goiabas. Na CEASA e na CEAGESP foram realizados levantamentos para quantificar as doenças pós-colheita em goiabas. Em duas áreas de produção de goiabas quantificaram-se as doenças quiescentes da goiaba em duas áreas de produção pelo método de detecção precoce de infecções quiescentes. Armadilhas caça-esporos foram colocadas em plantas para quantificar esporos carregados pela chuva. Talhões com e sem restos de cultura ao redor das plantas foram avaliados. Experimentos in vitro e in vivo foram realizados com diferentes tratamentos de atmosfera controlada para o controle de antracnose e pinta preta da goiaba. A temperatura ótima para a colonização de G. psidii foi de 30 ºC, atingindo incidência de 100% com 24 horas de molhamento, 10 dias após incubação. As principais doenças observadas nos mercados atacadistas e nas duas áreas de produção de goiabas foram antracnose, pinta preta e podridão de Fusicocum, com incidências máximas de 56,6%, 46,1% e 41,9%, respectivamente nos mercados atacadistas e máximas de 86,4%, 62,0% e 44,0%, respectivamente, nas áreas de produção de goiabas, 10 dias após incubação a 25 ºC. A antracnose foi a única doença observada desde a flor até em frutos maduros. Houve correlação direta entre a temperatura máxima combinada ou não com a precipitação acumulada e a incidência de antracnose nos frutos. Todos os isolados de Colletotrichum obtidos de frutos doentes foram identificados como C. gloeosporioides. Não houve diferença significativa nas incidências das principais doenças quiescentes da goiaba para as áreas com e sem restos culturais. A ocorrência de chuva no florescimento e nos estádios iniciais de desenvolvimento do fruto associada a temperaturas elevadas resultaram em incidências elevadas das principais doenças quiescentes da goiaba \'Kumagai\' em pós-colheita. O tratamento 30% CO2 + 70% O2 proporcionou maiores reduções no crescimento micelial dos fungos avaliados e na incidência de frutos doentes, após 4 dias sob atmosfera controlada. Frutos armazenados em atmosferas contendo 60% N2O + 20% O2 + 20% N2 e 30% CO2 + 70% O2 apresentaram menores severidade da antracnose e pinta preta, respectivamente em goiabas. / Post-harvest diseases in guavas may represent damages from 20 to 40%. Environmental conditions and disease management, before or after harvesting, are among their major causes. Standards proposed by the Integrated Production Fruit (IPF) ensure fruit quality and sustainable production with rational use of agrochemicals. Using the white-fleshed variety Kumagai, the objectives were: (i) to determine the environmental conditions favorable to the natural colonization of Guignardia psidii in guava (ii) to quantify the incidence of major post-harvest diseases of guava at the main wholesale markets of São Paulo state, (iii) to detect and quantify the quiescent diseases from flower to fruit in the harvest point (iv) to evaluate the effect of controlled atmosphere using high concentrations of O2 to control the main post-harvest diseases of guava. Experiments were conducted under controlled conditions to determine the effect of environmental conditions on the colonization of G. psidii on guavas. Surveys were carried out to quantify the postharvest diseases in guavas in CEASA and CEAGESP. The quiescent diseases of guava were quantified in two production areas by the method of early detection of quiescent infection. Inverted-bottle samplers were placed on plants to quantify spores carried by rain. Plots with and without crop residues around the plants were evaluated. Experiments in vitro and in vivo experiments were performed with different controlled atmosphere treatments for control of anthracnose and black spot of guava. The optimum temperature for G. psidii colonization was 30 °C, reaching 100% incidence with 24 hours of wetness, 10 days after incubation. The main diseases observed in the wholesale markets and in the two production areas were guava anthracnose, black spot and Fusicocum rot. The highest incidences were 56.6%, 46.1% and 41.9%, for anthracnose, black spot and Fusicocum rot, respectively, stored at 25 °C. In the field, fruits presented maximum incidences of 86.4% for anthracnose, 62.0% for black spot and 44.0% for Fusicocum rot. Anthracnose was the only post-harvest quiescent disease that was observed from the flower to the mature fruit. There was direct correlation between the maximum temperature and the incidence of anthracnose regardless of rainfall. Colletotrichum sp. strains obtained from diseased fruit were identified as C. gloeosporioides. There was no significant difference in the incidence of major diseases of guava quiescent in areas with and without crop residues around the plants. The occurrence of rain during flowering and early stages of fruit development associated with high temperatures resulted in high diseases incidences of major diseases quiescent guava \'Kumagai\' in post-harvest. The treatment 30% CO2 + 70% provided greater reductions in mycelial growth of fungi and incidence of diseased fruits, after 4 days under controlled atmosphere. Fruit stored with 60% N2O + 20% O2 + 20% N2 and 30% CO2 + 70% O2 showed lower severity of anthracnose and black spot, respectively.

As doenças pós-colheita em goiabas podem representar danos entre 20 e 40%, em função de condições ambientais e manejo integrado de doenças tanto antes quanto após a colheita. A adequação dos produtores às normas do Programa Integrado de Frutas (PIF) garante a obtenção de frutos com qualidade, produzidos de forma sustentável. Porém, exige o uso racional de agroquímicos durante as fases de produção da fruta. Neste contexto, utilizando a variedade Kumagai de polpa branca, os objetivos deste trabalho foram: (i) determinar as condições ambientais favoráveis à colonização natural de Guignardia psidii em goiabas; (ii) quantificar a incidência das doenças pós-colheita em goiabas nos dois principais mercados atacadistas do Estado de São Paulo; (iii) detectar e quantificar as doenças quiescentes desde a flor até em frutos no ponto de colheita; (iv) verificar o efeito da atmosfera controlada utilizando altas concentrações de O2 no controle das principais doenças pós-colheita da goiaba. Experimentos em condições controladas foram conduzidos para determinar o efeito de condições ambientais na colonização de G. psidii em goiabas. Na CEASA e na CEAGESP foram realizados levantamentos para quantificar as doenças pós-colheita em goiabas. Em duas áreas de produção de goiabas quantificaram-se as doenças quiescentes da goiaba em duas áreas de produção pelo método de detecção precoce de infecções quiescentes. Armadilhas caça-esporos foram colocadas em plantas para quantificar esporos carregados pela chuva. Talhões com e sem restos de cultura ao redor das plantas foram avaliados. Experimentos in vitro e in vivo foram realizados com diferentes tratamentos de atmosfera controlada para o controle de antracnose e pinta preta da goiaba. A temperatura ótima para a colonização de G. psidii foi de 30 ºC, atingindo incidência de 100% com 24 horas de molhamento, 10 dias após incubação. As principais doenças observadas nos mercados atacadistas e nas duas áreas de produção de goiabas foram antracnose, pinta preta e podridão de Fusicocum, com incidências máximas de 56,6%, 46,1% e 41,9%, respectivamente nos mercados atacadistas e máximas de 86,4%, 62,0% e 44,0%, respectivamente, nas áreas de produção de goiabas, 10 dias após incubação a 25 ºC. A antracnose foi a única doença observada desde a flor até em frutos maduros. Houve correlação direta entre a temperatura máxima combinada ou não com a precipitação acumulada e a incidência de antracnose nos frutos. Todos os isolados de Colletotrichum obtidos de frutos doentes foram identificados como C. gloeosporioides. Não houve diferença significativa nas incidências das principais doenças quiescentes da goiaba para as áreas com e sem restos culturais. A ocorrência de chuva no florescimento e nos estádios iniciais de desenvolvimento do fruto associada a temperaturas elevadas resultaram em incidências elevadas das principais doenças quiescentes da goiaba \'Kumagai\' em pós-colheita. O tratamento 30% CO2 + 70% O2 proporcionou maiores reduções no crescimento micelial dos fungos avaliados e na incidência de frutos doentes, após 4 dias sob atmosfera controlada. Frutos armazenados em atmosferas contendo 60% N2O + 20% O2 + 20% N2 e 30% CO2 + 70% O2 apresentaram menores severidade da antracnose e pinta preta, respectivamente em goiabas. / Post-harvest diseases in guavas may represent damages from 20 to 40%. Environmental conditions and disease management, before or after harvesting, are among their major causes. Standards proposed by the Integrated Production Fruit (IPF) ensure fruit quality and sustainable production with rational use of agrochemicals. Using the white-fleshed variety Kumagai, the objectives were: (i) to determine the environmental conditions favorable to the natural colonization of Guignardia psidii in guava (ii) to quantify the incidence of major post-harvest diseases of guava at the main wholesale markets of São Paulo state, (iii) to detect and quantify the quiescent diseases from flower to fruit in the harvest point (iv) to evaluate the effect of controlled atmosphere using high concentrations of O2 to control the main post-harvest diseases of guava. Experiments were conducted under controlled conditions to determine the effect of environmental conditions on the colonization of G. psidii on guavas. Surveys were carried out to quantify the postharvest diseases in guavas in CEASA and CEAGESP. The quiescent diseases of guava were quantified in two production areas by the method of early detection of quiescent infection. Inverted-bottle samplers were placed on plants to quantify spores carried by rain. Plots with and without crop residues around the plants were evaluated. Experiments in vitro and in vivo experiments were performed with different controlled atmosphere treatments for control of anthracnose and black spot of guava. The optimum temperature for G. psidii colonization was 30 °C, reaching 100% incidence with 24 hours of wetness, 10 days after incubation. The main diseases observed in the wholesale markets and in the two production areas were guava anthracnose, black spot and Fusicocum rot. The highest incidences were 56.6%, 46.1% and 41.9%, for anthracnose, black spot and Fusicocum rot, respectively, stored at 25 °C. In the field, fruits presented maximum incidences of 86.4% for anthracnose, 62.0% for black spot and 44.0% for Fusicocum rot. Anthracnose was the only post-harvest quiescent disease that was observed from the flower to the mature fruit. There was direct correlation between the maximum temperature and the incidence of anthracnose regardless of rainfall. Colletotrichum sp. strains obtained from diseased fruit were identified as C. gloeosporioides. There was no significant difference in the incidence of major diseases of guava quiescent in areas with and without crop residues around the plants. The occurrence of rain during flowering and early stages of fruit development associated with high temperatures resulted in high diseases incidences of major diseases quiescent guava \'Kumagai\' in post-harvest. The treatment 30% CO2 + 70% provided greater reductions in mycelial growth of fungi and incidence of diseased fruits, after 4 days under controlled atmosphere. Fruit stored with 60% N2O + 20% O2 + 20% N2 and 30% CO2 + 70% O2 showed lower severity of anthracnose and black spot, respectively.