Submitted by (lucia.rodrigues@ufrpe.br) on 2017-02-17T14:46:49Z No. of bitstreams: 1 Cicero Nicolini.pdf: 204101 bytes, checksum: 7157eb0dfbcf608b64b0ae9bbbaf5c05 (MD5) / Made available in DSpace on 2017-02-17T14:46:49Z (GMT). No. of bitstreams: 1 Cicero Nicolini.pdf: 204101 bytes, checksum: 7157eb0dfbcf608b64b0ae9bbbaf5c05 (MD5) Previous issue date: 2008-03-03 / The Alternaria black spot is one of the most common and destructive diseases of brassica species. This disease can be caused by several species of Alternaria, although A. brassicicola is predominant species in both conventional and organic crops in Brazil. Since commercial cultivars of brassica with acceptable levels of disease resistance are not available, the disease control in conventional production system is based on the fungicide applications, while in the organic production system the disease control on relays on cultural methods. The objective of this study is to assess the sensitivity of 112 isolates of A. brassicicola to fungicide groups: benzimidazoles (carbendazim), dicarboximides (iprodione), triazoles (tebuconazole) and strobilurines (azoxystrobin). The isolates were evaluated in vitro to obtain the concentration capable of inhibiting 50% of the mycelial growth (CL50) and separated in four classes depending on the sensibility to the tested fungicides. All the isolated of A. brassicicola were sensitive the iprodione, with CL50 values below to 0.1 mg i.a./L. Most of the isolates originating from conventional (92.9%) and organic (96.4%) were middling resistant the azoxystrobin, while an isolated (CFM-576) was highly resistant. In relation to tebuconazole, only isolated sensitive (42.9%) and lightly resistant (57.1%) were observed. There was nosignificant difference between the isolates of A. brassicicola originated either from conventional or organic systems and brassica types regarding the levels of sensitivity to the fungicides. / A alternariose é uma das doenças foliares mais comuns e destrutivas das brássicas, podendo ser causada por várias espécies de Alternaria, embora A. brassicicola seja a espécie predominante em plantios convencionais e orgânicos no Brasil. Como inexistem cultivares comerciais de brássicas com níveis aceitáveis de resistência à doença, no sistema de produção convencional o controle da doença se baseia na aplicação de fungicidas, enquanto no sistema orgânico em métodos culturais. O presente trabalho teve como objetivo avaliar a sensibilidade de 112 isolados de A. brassicicola oriundos de cultivos convencionais e orgânicos de brássicas a fungicidas dos grupos dicarboximidas (iprodione), triazóis (tebuconazole) e estrobilurinas (azoxystrobin). Os isolados foram avaliados in vitro visando obter a concentração capaz de inibir 50% do crescimento micelial (CL50) e separados em quatro classes dependendo da sua sensibilidade aos fungicidas testados. Todos os isolados de A. brassicicola foram sensíveis a iprodione, com valores de CL50 inferiores a 0,1 mg i.a./L. A maioria dos isolados oriundos de cultivos convencionais (92,9%) e orgânicos (96,4%) se comportou como medianamente resistente a azoxystrobin, enquanto um isolado (CFM-576) foi altamente resistente. Em relação a tebuconazole, foram constatados somente isolados sensíveis (42,9%) e ligeiramente resistentes (57,1%). Não foi encontrada diferença significativa quanto à sensibilidade aos fungicidas testados entre os isolados de A. brassicicola oriundos de cultivos convencionais e orgânicos, bem como, coletados de diferentes tipos de brássicas.

O fungo Phakopsora pachyrhizi Syd. & Syd, representa grande ameaça à sojicultura nas principais regiões produtoras do mundo, onde perdas significativas foram relatadas. Na quantificação de danos causados por esta doença muitas são as variáveis a serem estudadas como Área abaixo da curva de progresso da doença (AACPD), Absorção da área foliar sadia (HAA) e Duração da área foliar sadia (HAD), além das curvas de progresso da doença. Visando seu controle químico torna-se necessário a aplicação de defensivos agrícolas, os quais podem afetar o crescimento e metabolismo das plantas, resultando em consequências negativas ou positivas. Existem relatos de que a aplicação de fungicidas do grupo das estrobilurinas na cultura da soja tem promovido aumento de produtividade mesmo em locais sem incidência de doenças, indicando que alterações de ordem fisiológica devem ser quantificadas. Este estudo foi desenvolvido com o objetivo de verificar a influência dos diferentes fungicidas no progresso da doença, bem como suas implicações nas variáveis referentes à área foliar sadia, no crescimento e na produtividade de duas cultivares semeadas em época tardia. Os tratamentos testados nas duas cultivares foram: 1. Testemunha; 2. Testemunha com herbicidas (V4); 3. Herbicida + pyraclostrobin (V4); 4. Herbicidas + pyraclostrobin (V4) e pyraclostrobin + epoxiconazole (R2); 5. Herbicidas + pyraclostrobin (V4) e pyraclostrobin + epoxiconazole (R2 e R5.1); 6. Herbicida + pyraclostrobin (V4), pyraclostrobin + epoxiconazole (R2) e epoxiconazole (R5.1) 7. Herbicida + pyraclostrobin (V4) e epoxiconazole (R2 e R5.1); 8. Herbicida (V4) e pyraclostrobin + epoxiconazole (R2 e R5.1). A análise dos resultados permitiu afirmar que a associação da estrobilurina (pyraclostrobin) com bentazon e chlorimuron-ethyl, em V4, possibilitou a antecipação da recuperação dos efeitos provocados pelos herbicidas citados. A mistura de estrobilurinas associado à triazol (pyraclostrobin + epoxiconazole) promoveu maior controle e período residual sobre o fungo Phakopsora pachyrhizi, em relação ao fungicida do grupo dos triazóis (epoxiconazole). O modelo logístico foi o que mais se adequou à severidade média das avaliações e à curva de progresso da doença. Para o terço inferior, posição da copa mais propicia ao desenvolvimento da doença, o modelo logístico com taxa variável foi o que mais se ajustou aos dados obtidos. As variáveis AACPD, HAA e HAD podem ser consideradas apropriadas para se quantificar os danos provocados por esta doença. Na análise de crescimento, foi observado que a referida mistura aplicada em R2 e R5.1, promoveu maior índice de área foliar e acúmulo de massa seca de parte aérea, resultando em maiores valores de taxa de crescimento absoluto (TCA), taxa de crescimento relativo (TCR), taxa assimilatória líquida (TAL) e taxa de crescimento da cultura (TCC) em estádios reprodutivo, diferenciando, inclusive, dos tratamentos com aplicação isolada de triazóis (epoxiconazole). Ainda, a utilização dos fungicidas estudados, a partir de R2, melhorou a qualidade fisiológica de sementes. Assim, de acordo com estes resultados a utilização da mistura pyraclostrobin + epoxiconazole resultou no aumento significativo dos valores dos componentes de produção, possibilitando a obtenção de ganhos de produtividade. / Phakopsora pachyrhizi Syd. & Syd. is the worst threat for soybean crop in the main producers regions around the world, where significant loses has been observed. Many variables in the quantification of damage of this disease have to be studied, such as area under the disease progress curve (AUDPC), healthy leaf area absorption (HAA), healthy leaf area duration (HAD), in addition to disease progress curves. Aiming the chemical control of this disease, it becomes necessary fungicide applications, which may change the metabolism and the growth of the plant, resulting in negative or positive alterations. There are reports showing that fungicide applications of the strobilurin group on soybean crop have promoted yield enhancement, even in situations without the incidence of diseases, indicating that physiologic changes should be quantified. This study aimed at evaluating the influence of different fungicides on the progress of the disease and its implications on variables related to healthy leaf area, the growth and productivity of two cultivars sowed in late season. The treatments were evaluated in two cultivars: 1. Control; 2. Control with herbicides (V4); 3. Herbicide + pyraclostrobin (V4); 4. Herbicide + pyraclostrobin (V4) and pyraclostrobin + epoxiconazole (R2); 5. Herbicide + pyraclostrobin (V4) and pyraclostrobin + epoxiconazole (R2 and R5.1); 6. Herbicide + pyraclostrobin (V4), pyraclostrobin + epoxiconazole (R2) and epoxiconazole (R5.1) 7. Herbicide + pyraclostrobin (V4) and epoxiconazole (R2 and R5.1) 8. Herbicide (V4) and pyraclostrobin + epoxiconazole (R2 and R5.1). The analysis of the results obtained has made it possible to conclude that the association of pyraclostrobin with bentazon e chlorimuron-ethyl, in V4, allowed an early recovery from the effects caused by the above-mentioned herbicides. The spraying of strobilurins group associated with triazole (pyraclostrobin + epoxiconazole) promoted greater control and longer residual period of Phakopsora pachyrhizi, in relation to the group of ergosterol biosynthesis inhibitors fungicide (epoxiconazole). The logistic model was the one which best adapted to the mean severity ratings and the disease progress curve. At the bottom of the canopy, the most favorable position to the development of the disease, the logistic model with variable rate was the model that most fitted the obtained data. The variables AUDPC, HAA and HAD can be considered suitable to quantify the damage caused by this disease. On the growth analysis, it was observed that the mixture cited above, applied on R2 and R5.1, promoted higher leaf area index and shoots dry mass accumulation, resulting in increase of absolute growth rate (AGR), relative growth rate (RGR), net assimilation rate (NAR) and crop growth rate (CGR) in reproductive stages, differing even from the treatment with single triazole applications. The use of these studied fungicides, starting from stage R2, provided better physiological quality of seeds. Thus, according to these results, the application of strobilurin group associated with triazoles (pyraclostrobin + epoxiconazole) fungicide resulted in significant increase in values of the productivity compounds, resulting in yield gains.

O fungo Phakopsora pachyrhizi Syd. & Syd, representa grande ameaça à sojicultura nas principais regiões produtoras do mundo, onde perdas significativas foram relatadas. Na quantificação de danos causados por esta doença muitas são as variáveis a serem estudadas como Área abaixo da curva de progresso da doença (AACPD), Absorção da área foliar sadia (HAA) e Duração da área foliar sadia (HAD), além das curvas de progresso da doença. Visando seu controle químico torna-se necessário a aplicação de defensivos agrícolas, os quais podem afetar o crescimento e metabolismo das plantas, resultando em consequências negativas ou positivas. Existem relatos de que a aplicação de fungicidas do grupo das estrobilurinas na cultura da soja tem promovido aumento de produtividade mesmo em locais sem incidência de doenças, indicando que alterações de ordem fisiológica devem ser quantificadas. Este estudo foi desenvolvido com o objetivo de verificar a influência dos diferentes fungicidas no progresso da doença, bem como suas implicações nas variáveis referentes à área foliar sadia, no crescimento e na produtividade de duas cultivares semeadas em época tardia. Os tratamentos testados nas duas cultivares foram: 1. Testemunha; 2. Testemunha com herbicidas (V4); 3. Herbicida + pyraclostrobin (V4); 4. Herbicidas + pyraclostrobin (V4) e pyraclostrobin + epoxiconazole (R2); 5. Herbicidas + pyraclostrobin (V4) e pyraclostrobin + epoxiconazole (R2 e R5.1); 6. Herbicida + pyraclostrobin (V4), pyraclostrobin + epoxiconazole (R2) e epoxiconazole (R5.1) 7. Herbicida + pyraclostrobin (V4) e epoxiconazole (R2 e R5.1); 8. Herbicida (V4) e pyraclostrobin + epoxiconazole (R2 e R5.1). A análise dos resultados permitiu afirmar que a associação da estrobilurina (pyraclostrobin) com bentazon e chlorimuron-ethyl, em V4, possibilitou a antecipação da recuperação dos efeitos provocados pelos herbicidas citados. A mistura de estrobilurinas associado à triazol (pyraclostrobin + epoxiconazole) promoveu maior controle e período residual sobre o fungo Phakopsora pachyrhizi, em relação ao fungicida do grupo dos triazóis (epoxiconazole). O modelo logístico foi o que mais se adequou à severidade média das avaliações e à curva de progresso da doença. Para o terço inferior, posição da copa mais propicia ao desenvolvimento da doença, o modelo logístico com taxa variável foi o que mais se ajustou aos dados obtidos. As variáveis AACPD, HAA e HAD podem ser consideradas apropriadas para se quantificar os danos provocados por esta doença. Na análise de crescimento, foi observado que a referida mistura aplicada em R2 e R5.1, promoveu maior índice de área foliar e acúmulo de massa seca de parte aérea, resultando em maiores valores de taxa de crescimento absoluto (TCA), taxa de crescimento relativo (TCR), taxa assimilatória líquida (TAL) e taxa de crescimento da cultura (TCC) em estádios reprodutivo, diferenciando, inclusive, dos tratamentos com aplicação isolada de triazóis (epoxiconazole). Ainda, a utilização dos fungicidas estudados, a partir de R2, melhorou a qualidade fisiológica de sementes. Assim, de acordo com estes resultados a utilização da mistura pyraclostrobin + epoxiconazole resultou no aumento significativo dos valores dos componentes de produção, possibilitando a obtenção de ganhos de produtividade. / Phakopsora pachyrhizi Syd. & Syd. is the worst threat for soybean crop in the main producers regions around the world, where significant loses has been observed. Many variables in the quantification of damage of this disease have to be studied, such as area under the disease progress curve (AUDPC), healthy leaf area absorption (HAA), healthy leaf area duration (HAD), in addition to disease progress curves. Aiming the chemical control of this disease, it becomes necessary fungicide applications, which may change the metabolism and the growth of the plant, resulting in negative or positive alterations. There are reports showing that fungicide applications of the strobilurin group on soybean crop have promoted yield enhancement, even in situations without the incidence of diseases, indicating that physiologic changes should be quantified. This study aimed at evaluating the influence of different fungicides on the progress of the disease and its implications on variables related to healthy leaf area, the growth and productivity of two cultivars sowed in late season. The treatments were evaluated in two cultivars: 1. Control; 2. Control with herbicides (V4); 3. Herbicide + pyraclostrobin (V4); 4. Herbicide + pyraclostrobin (V4) and pyraclostrobin + epoxiconazole (R2); 5. Herbicide + pyraclostrobin (V4) and pyraclostrobin + epoxiconazole (R2 and R5.1); 6. Herbicide + pyraclostrobin (V4), pyraclostrobin + epoxiconazole (R2) and epoxiconazole (R5.1) 7. Herbicide + pyraclostrobin (V4) and epoxiconazole (R2 and R5.1) 8. Herbicide (V4) and pyraclostrobin + epoxiconazole (R2 and R5.1). The analysis of the results obtained has made it possible to conclude that the association of pyraclostrobin with bentazon e chlorimuron-ethyl, in V4, allowed an early recovery from the effects caused by the above-mentioned herbicides. The spraying of strobilurins group associated with triazole (pyraclostrobin + epoxiconazole) promoted greater control and longer residual period of Phakopsora pachyrhizi, in relation to the group of ergosterol biosynthesis inhibitors fungicide (epoxiconazole). The logistic model was the one which best adapted to the mean severity ratings and the disease progress curve. At the bottom of the canopy, the most favorable position to the development of the disease, the logistic model with variable rate was the model that most fitted the obtained data. The variables AUDPC, HAA and HAD can be considered suitable to quantify the damage caused by this disease. On the growth analysis, it was observed that the mixture cited above, applied on R2 and R5.1, promoted higher leaf area index and shoots dry mass accumulation, resulting in increase of absolute growth rate (AGR), relative growth rate (RGR), net assimilation rate (NAR) and crop growth rate (CGR) in reproductive stages, differing even from the treatment with single triazole applications. The use of these studied fungicides, starting from stage R2, provided better physiological quality of seeds. Thus, according to these results, the application of strobilurin group associated with triazoles (pyraclostrobin + epoxiconazole) fungicide resulted in significant increase in values of the productivity compounds, resulting in yield gains.

Certains pesticides présentent une très bonne activité biologique en serre, lorsqu’ils sont protégés du rayonnement UV, mais pas en champs lorsqu’ils sont exposés à la totalité de la lumière solaire. Une dégradation photochimique par le rayonnement UV est alors suspectée. C’est le cas de la famille de fongicides contenant un groupement oxime dont nous avons étudié en détail la photodégradation d’un point de vue expérimental et théorique. La cinétique de phototransformation de ces fongicides a été mesurée en solution et en phase solide et les photoproduits de réaction ont été identifiés et quantifiés. L’ensemble des résultats nous a alors permis de proposer un mécanisme de photodégradation. Ces fongicides subissent à la fois une photoisomérisation et une photodégradation par rupture homolytique de la liaison oxime. Le rôle de certains éléments structuraux dans ces transformations a pu être établi grâce à plusieurs analogues. Une étude de modélisation moléculaire menée en parallèle a permis de déterminer la nature des voies réactionnelles mises en jeu après l’excitation de la molécule et ainsi d’expliquer les observations expérimentales. Ce travail avait pour objectif d’améliorer la photostabilité de cette famille de fongicides par des modifications structurales tout en respectant l’activité biologique par ailleurs tout à fait remarquable de ces composés. Le remplacement de l’oxime par un oxétane préparé par une réaction de Paternò-Büchi a été envisagé. / Some pesticides present a great biological activity in green house, while they are protected from UV radiations, but not in the field, while they are exposed to the whole spectrum of solar light. A photochemical degradation by UV light is then suspected. That is the case of the group of fungicides which contain an oxim moiety and that we studied the photodegradation in detail, both from experimental and theoretical points of view. The kinetics of phototransformation of these fungicides have been mesured in solution and in the solid phase and photoproducts have been identified and quantified. These results allowed us to propose a mecanism of photodegradation. These fungicides undergo simultanously a photoisomerisation and a photodegradation by a homolytic cleavage of the oxim bond. The role of some structural elements in these transformations has been set up thanks to several analogues. A parallel study of molecular modelisation allowed the determination of the nature of reactive paths followed after the excitation of the molecule and therefore the explanation of experimental observations. The objective of this work was to improve the photostability of this group of fungicides by structural modifications while keeping the remarquable biological activity of these compounds. The replacement of the oxim moiety by an oxetane prepared by a Paternò-Büchi reaction has been considered.

Phytophthora infestans (Mont) de Bary is a devastating pathogen in potato producing regions around the world. Populations of the organism in Canada shifted during the mid-1990’s as the US-1 strain (A1, metalaxyl-sensitive) was displaced by the highly aggressive, US-8 strain (A2, metalaxyl-insensitive). An increase in the incidence and severity of late blight has followed. Late blight is controlled by cultural practices aimed at eliminating disease sources and by the application of foliar fungicides. Tubers can become infected at harvest from contact with blighted vines leading to severe losses in storage. In many production areas, growers desiccate vines two to three weeks prior to harvest to reduce late blight tuber rot. However, in Manitoba, because of the loss of potential yield that results from vine killing prior to harvest in a late maturing cultivar such as Russet Burbank, growers are reluctant to adopt this practice. The objective of this study was to develop recommendations for preharvest management practices that reduce storage losses due to late blight. Field trials were conducted in 1997 and 1998 to investigate the effect of vine desiccation with diquat and/or a late season application of chlorothalonil and copper hydroxide on yield, processing quality, and disease development in storage. Desiccating vines with diquat two weeks prior to harvest reduced yield and tuber size. Compared to the untreated control, the largest reductions in marketable yield were observed for the early September harvest. By the late September harvest, however, the effect of vine killing in reducing marketable yield was less apparent. Specific gravity was lower in the vine killed treatment for all harvest dates in 1997 and in the early and mid September harvests in 1998. Vine killing did not contribute to elevated levels of reducing sugars or consistently darker fry colour at harvest or during storage. Skin-set was improved when vines were desiccated for all harvest dates in 1997 and at the early September harvest date in 1998. Vine killing reduced tuber rot in storage caused by Fusarium dry rot and Pythium leak for the early and mid September harvest dates in 1997. The incidence of late blight tuber rot was reduced in storage for the early September harvest in 1998 when vines were desiccated. The late-season application of chlorothalonil and copper hydroxide did not reduce tuber rot in storage in storage either year. Results from this study indicate that vine killing two weeks before an early to mid- September harvest is not recommended in Manitoba because of reductions in yield and specific gravity. Alternative management practices to reduce late blight tuber rot in storage should be investigated. / February 2005

Field studies were conducted in Ontario in 2009 and 2010 to determine the tolerance of winter wheat to herbicide-fungicide tank-mixtures, and the tolerance of winter wheat underseeded red clover to commonly used herbicides applied at three timings. Tank-mixtures including the fungicide tebuconazole caused injury at early and late timings, while mixtures including the herbicide bromoxynil/MCPA were most injurious when applied late in the season. Injury was transient with no yield reductions observed. MCPA/mecoprop/dicamba caused significant yield reductions when applied at normal and late timings, but did not reduce yield when applied early. The herbicides prosulfuron+bromoxynil and pyrasulfotole/bromoxynil were most injurious to underseeded red clover and reduced clover biomass regardless of application timing. Herbicides and herbicide-fungicide tank-mixtures applied early, during cold temperatures do not increase winter wheat or red clover sensitivity; the likelihood of injury is greatest when applications of these products occur late. / Grain Farmers of Ontario; Ontario Ministry of Agriculture, Food, and Rural Affairs; Agriculture Adaptation Council of Canada

Phytophthora infestans (Mont) de Bary is a devastating pathogen in potato producing regions around the world. Populations of the organism in Canada shifted during the mid-1990’s as the US-1 strain (A1, metalaxyl-sensitive) was displaced by the highly aggressive, US-8 strain (A2, metalaxyl-insensitive). An increase in the incidence and severity of late blight has followed. Late blight is controlled by cultural practices aimed at eliminating disease sources and by the application of foliar fungicides. Tubers can become infected at harvest from contact with blighted vines leading to severe losses in storage. In many production areas, growers desiccate vines two to three weeks prior to harvest to reduce late blight tuber rot. However, in Manitoba, because of the loss of potential yield that results from vine killing prior to harvest in a late maturing cultivar such as Russet Burbank, growers are reluctant to adopt this practice. The objective of this study was to develop recommendations for preharvest management practices that reduce storage losses due to late blight. Field trials were conducted in 1997 and 1998 to investigate the effect of vine desiccation with diquat and/or a late season application of chlorothalonil and copper hydroxide on yield, processing quality, and disease development in storage. Desiccating vines with diquat two weeks prior to harvest reduced yield and tuber size. Compared to the untreated control, the largest reductions in marketable yield were observed for the early September harvest. By the late September harvest, however, the effect of vine killing in reducing marketable yield was less apparent. Specific gravity was lower in the vine killed treatment for all harvest dates in 1997 and in the early and mid September harvests in 1998. Vine killing did not contribute to elevated levels of reducing sugars or consistently darker fry colour at harvest or during storage. Skin-set was improved when vines were desiccated for all harvest dates in 1997 and at the early September harvest date in 1998. Vine killing reduced tuber rot in storage caused by Fusarium dry rot and Pythium leak for the early and mid September harvest dates in 1997. The incidence of late blight tuber rot was reduced in storage for the early September harvest in 1998 when vines were desiccated. The late-season application of chlorothalonil and copper hydroxide did not reduce tuber rot in storage in storage either year. Results from this study indicate that vine killing two weeks before an early to mid- September harvest is not recommended in Manitoba because of reductions in yield and specific gravity. Alternative management practices to reduce late blight tuber rot in storage should be investigated.

Phytophthora infestans (Mont) de Bary is a devastating pathogen in potato producing regions around the world. Populations of the organism in Canada shifted during the mid-1990’s as the US-1 strain (A1, metalaxyl-sensitive) was displaced by the highly aggressive, US-8 strain (A2, metalaxyl-insensitive). An increase in the incidence and severity of late blight has followed. Late blight is controlled by cultural practices aimed at eliminating disease sources and by the application of foliar fungicides. Tubers can become infected at harvest from contact with blighted vines leading to severe losses in storage. In many production areas, growers desiccate vines two to three weeks prior to harvest to reduce late blight tuber rot. However, in Manitoba, because of the loss of potential yield that results from vine killing prior to harvest in a late maturing cultivar such as Russet Burbank, growers are reluctant to adopt this practice. The objective of this study was to develop recommendations for preharvest management practices that reduce storage losses due to late blight. Field trials were conducted in 1997 and 1998 to investigate the effect of vine desiccation with diquat and/or a late season application of chlorothalonil and copper hydroxide on yield, processing quality, and disease development in storage. Desiccating vines with diquat two weeks prior to harvest reduced yield and tuber size. Compared to the untreated control, the largest reductions in marketable yield were observed for the early September harvest. By the late September harvest, however, the effect of vine killing in reducing marketable yield was less apparent. Specific gravity was lower in the vine killed treatment for all harvest dates in 1997 and in the early and mid September harvests in 1998. Vine killing did not contribute to elevated levels of reducing sugars or consistently darker fry colour at harvest or during storage. Skin-set was improved when vines were desiccated for all harvest dates in 1997 and at the early September harvest date in 1998. Vine killing reduced tuber rot in storage caused by Fusarium dry rot and Pythium leak for the early and mid September harvest dates in 1997. The incidence of late blight tuber rot was reduced in storage for the early September harvest in 1998 when vines were desiccated. The late-season application of chlorothalonil and copper hydroxide did not reduce tuber rot in storage in storage either year. Results from this study indicate that vine killing two weeks before an early to mid- September harvest is not recommended in Manitoba because of reductions in yield and specific gravity. Alternative management practices to reduce late blight tuber rot in storage should be investigated.

The papaya culture is extensively cultivated in the world, where Brazil meets as worldwide the producing greater. Amongst the problems main inherent to the culture, the root and fruit rots are distinguished, caused by Phytophthora palmivora. The present work had for objective to control P. palmivora in seedling of papaya cv. Sunrise solo, through methods of biological, physical and chemical control. They had been tested four Trichoderma isolated (T. koningii - T3; T. harzianum - T13; Trichoderma sp. - T152D and T. polysporum - TP) and five fungicides "in vitro" (copper oxychloride - 2; 3 e 4g/L; mancozeb - 2; 3 e 4g/L; metalaxyl + mancozeb - 2,5; 3,5 e 4g/L; thiophanate-methyl - 6; 7 e 8g/L and carbendazim - 0,5; 1,0 e 1,5mL/L) and "in vivo", as well as the solarization of the substratum in solar collectors. They had been made still, test of volatile, not volatile metabolites and hyperparasitism for the Trichoderma isolated. In the biological control "in vitro", used the plate technique, while in the in vivo control, the substratum was dealt with Trichoderma of isolated and integrated form, before the infestation of the ground. In the chemical control, the fungicides had been tested "in vitro" adding them in BDA medium, while "in vivo" the seedlings roots had been immersed during 10 minutes in the fungicides solution. The solarization of the substratum was carried during 24, 48 and 72 hours, in solar collectors of 10 and 15 cm of diameter, becoming infested itself, previously the substratum with the pathogen (40 mL of inocule with approximately 20 sporangia for mL/ vase). The Trichoderma isolated T3, T13 and TP had been most efficient in the inhibition of the growth of P. palmivora "in vitro", however, only the isolated TP produced volatile and not volatile metabolites. On the other hand, all the isolated ones had presented capacity to hyperparasite the pathogen. In the biological control "in vivo" no isolated one was capable to reduce the severity of the disease. The solarization of the substratum increased significantly the seedlings survival, when compared to the witness. It didn t have significant differences between the periods of solar exposition, however, the diameter of 15 cm presented one better efficiency, with 87% of seedlings survival. The products most efficient in the pathogen inhibition "in vitro" had been oxicloreto de cobre, mancozeb and metalaxyl + mancozeb, while "in vivo" the five fungicides had presented similar efficiency, not having significant difference between the dosages tested. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A cultura do mamoeiro é extensamente cultivada no mundo tendo o Brasil como o maior produtor. Dentre os principais problemas inerentes à cultura, destacam-se as podridões do pé e do fruto, causadas por Phytophthora palmivora. O presente trabalho teve por objetivo avaliar o controle de P. palmivora em plântulas de mamoeiro cv. Sunrise solo, utilizando métodos de controle biológico, físico e químico. Foram testados quatro isolados de Trichoderma (T. koningii - T3; T. harzianum - T13; Trichoderma sp. - T152D e T. polysporum - TP) e cinco fungicidas in vitro (oxicloreto de cobre - 2; 3 e 4g/L; mancozeb 2; 3 e 4g/L; metalaxyl + mancozeb 2,5; 3,5 e 4g/L; tiofanato metílico 6; 7 e 8g/L; e carbendazim 0,5; 1,0 e 1,5mL/L) e in vivo na dosagem recomendada pelo fabricante, bem como a solarização do substrato em coletores solares. Foram feitos ainda, testes de metabólitos voláteis, não voláteis e hiperparasitismo para os isolados de Trichoderma. No controle biológico in vitro , utilizou-se a técnica de confrontamento em cultivo pareado, enquanto no controle in vivo , o substrato foi tratado com os isolados de Trichoderma de forma isolada e integrada, antes da infestação do solo com o patógeno. No controle químico, os fungicidas foram testados in vitro adicionando-os ao meio BDA, enquanto in vivo as raízes das plântulas foram imersas durante 10 minutos na solução dos fungicidas. A solarização do substrato foi realizada durante 24, 48 e 72 horas, em coletores solares de 10 e 15 cm de diâmetro, infestando-se, previamente o substrato com o patógeno (40 mL do inoculo com aproximadamente 20 esporângios por mL / vaso). Os isolados de Trichoderma T3, T13 e TP foram os mais eficientes na inibição do crescimento de P. palmivora in vitro , no entanto, apenas o isolado TP produziu metabólitos voláteis e não voláteis. Por outro lado, todos os isolados apresentaram capacidade de hiperparasitar o patógeno. Já no controle biológico in vivo nenhum isolado foi capaz de reduzir a severidade da doença. A solarização do substrato aumentou significativamente a sobrevivência das plântulas quando comparada à testemunha. Não houve diferenças significativas entre os períodos de exposição solar, entretanto, o diâmetro de 15 cm apresentou uma melhor eficiência, com 87% de sobrevivência das plântulas. Os produtos mais eficientes na inibição do patógeno in vitro foram oxicloreto de cobre, mancozeb e metalaxyl + mancozeb, enquanto in vivo os cinco fungicidas apresentaram eficiência semelhante, não havendo diferença significativa entre as dosagens testadas.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to evaluate the severity of occurrence of septoria leaf spot in sunflower, its association with meteorological variables and its effect on yield of field irrigated sunflower. The experiments were conducted in Santa Maria - RS during the 2008 spring season and during the 2009 fall growing season, with sowings in September and in February, respectively. Observations of severity of septoria leaf spot were made throughout the crop cycle, and with a disease forecasting system different times for fungicide applications have been identified. Results show that a sequence of rainy days, with favorable temperatures to the pathogen, tend to contribute to the development of septoria leaf spot in sunflower. In contrast, when water needed by plants is restored by irrigation, even temperature is favorable to the pathogen, disease development rate is lower than during and within 10 days of rainy periods. There were observed differences in septória leaf spot severity between treatments with and without fungicide application, but were not related to the yield of sunflower achenes. Fungicide application according to the different treatments did not significantly affect achene yield either. Therefore, significant differences in the variables that represent the progression of the disease do not necessarily imply in significant differences in yield. / Neste trabalho objetivou-se verificar a severidade de ocorrência de mancha de septória em girassol, sua associação aos elementos meteorológicos e seu efeito na produtividade do girassol cultivado a campo sob irrigação. Os experimentos foram conduzidos em Santa Maria RS durante a safra de 2008 e safrinha de 2009, com semeaduras em setembro e fevereiro, respectivamente. Foram realizadas observações de severidade de mancha de septória durante todo o ciclo da cultura e, com o auxílio de um sistema de previsão de doenças, foram definidos diferentes momentos para as aplicações de fungicida. Os resultados demonstram que sequencias de dias chuvosos, com temperatura favorável ao patógeno, tendem a contribuir para o desenvolvimento da mancha de septória no girassol. Em compensação, quando a água necessária às plantas é reposta por meio de irrigações, mesmo que a temperatura seja favorável ao patógeno, a taxa de desenvolvimento da doença é menor do que durante e até 10 dias após períodos chuvosos. Foram verificadas diferenças de severidade observada de mancha de septória entre tratamentos com e sem aplicação de fungicida, mas essas não apresentaram relação significativa com a produtividade de aquênios do girassol. A aplicação de fungicida, conforme os diferentes tratamentos, também não apresentou associação significativa com a produção de aquênios. Portanto, diferenças significativas nas variáveis que representam a progressão da doença não implicam necessariamente em diferenças significativas de produtividade.