Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1913. / Reprints from Journal of agricultural research. Part 1: vol. IV, no. 2 (15 May 1915), p. 135-168, plates xvi-xxvi -- Part 2: vol. V, no. 1 (4 Oct. 1915), p. 55-57, plates i-ii -- Part 3: vol. IV, no. 4 (15 July 1915), p. 279-291, plates xliv-xlviii. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:34:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-17Bitstream added on 2014-06-13T19:24:04Z : No. of bitstreams: 1 correa_eb_dr_botfca.pdf: 989982 bytes, checksum: 71fbc2f45208972feb39e1343c4e6620 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O cultivo hidropônico de hortaliças vem crescendo e se tecnificando no Brasil. No entanto, podridões radiculares causadas por espécies de Pythium constituem um sério problema para a sua expansão. Uma vez o patógeno instalado no sistema, esse pode ser suprimido por meio da adição de microrganismos antagônicos. Além de suprimirem a podridão radicular, esses microrganismos introduzidos na solução nutritiva podem promover o crescimento das plantas, aumentando a receita do produtor. Entretanto, muitas vezes verifica-se baixa sobrevivência dos microrganismos adicionados na solução nutritiva. O desenvolvimento de formulações de agentes de controle biológico, principalmente de bactérias do gênero Pseudomonas, é um fator chave para a sua utilização em escala comercial. Devido à importância da podridão radicular em cultivos hidropônicos e o potencial de utilização do controle biológico da doença, os objetivos do presente trabalho foram (i) selecionar microrganismos residentes do manguezal como agentes de biocontrole da podridão radicular e promotores de crescimento em pepino hidropônico; (ii) avaliar o controle biológico da podridão radicular e a promoção de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03 em pimentão e alface cultivados em hidroponia; (iii) desenvolver uma formulação de Pseudomonas spp.. Em condições de casa de vegetação, Bacillus cereus AVIC-3-6, isolado de manguezal, protegeu as plantas de pepino do subdesenvolvimento causado pelo patógeno; Gordonia rubripertincta SO-3B-2 e Pseudomonas stutzeri MB-P3A-49, também isolados de manguezal, promoveram o crescimento de plantas de pepino não inoculadas com o patógeno. A adição de P. chlororaphis 63-28 e B. subtilis GB03 na solução nutritiva de pimentão cultivado em hidroponia e inoculado com P. aphanidermatum teve efeito positivo na supressão dos danos causados... / Hydroponic production of vegetables and flowers is increasing in Brazil, and the production technology is improving. A major factor constraining crop productivity is root rot caused by Pythium spp. Root rot severity can be reduced by the application of appropriate antagonistic microbes into the hydroponic nutrient solution or root zone of the crops. When in the root zone beneficial microbes may suppress progress of the root rot and increase crop productivity. However some beneficial microbes are not well-adapted to hydroponic environments and do not survive well in plant nutrient solutions. Ecologically-adapted microbes that are effective against root rot are a key factor for successful root rot control in hydroponic crops. The need for effective biological agents that are adapted to hydroponic systems and appropriately formulated for commercial use prompted investigations with the following aims: i) to select bacterial strains from among isolates obtained from mangrove swamps for effectiveness in controlling Pythium root rot in hydroponic cucumber; ii) to evaluate Pseudomonas chlororaphis 63-28 and Bacillus subtilis GB03 for controlling root rot and promoting growth of hydroponic lettuce and pepper; and iii) to assess formulations of Pseudomonas spp. for long-term shelf life. Bacillus cereus AVIC -3-6 from a mangrove reduced stunting of hydroponic cucumbers associated with Pythium root rot. Gordonia rubripertincta SO-3B-2 and Pseudomonas stutzeri MB-3PA-49 from a mangrove increased growth of healthy cucumber plants. Application of Pseudomonas chlororaphis 63-28 and Bacillus subtilis GB03 into the nutrient solution of hydroponic pepper suppressed root rot and increase the plant growth. Among tested formulations of Pseudomonas chlororaphis 63-28, a formulation with coconut fibre of 80% moisture content had the longest shelf life (up to 32 weeks) when kept at at 3ºC. We conclude that a)... (Complete abstract click electronic access below)

Resumo: O cultivo hidropônico de hortaliças vem crescendo e se tecnificando no Brasil. No entanto, podridões radiculares causadas por espécies de Pythium constituem um sério problema para a sua expansão. Uma vez o patógeno instalado no sistema, esse pode ser suprimido por meio da adição de microrganismos antagônicos. Além de suprimirem a podridão radicular, esses microrganismos introduzidos na solução nutritiva podem promover o crescimento das plantas, aumentando a receita do produtor. Entretanto, muitas vezes verifica-se baixa sobrevivência dos microrganismos adicionados na solução nutritiva. O desenvolvimento de formulações de agentes de controle biológico, principalmente de bactérias do gênero Pseudomonas, é um fator chave para a sua utilização em escala comercial. Devido à importância da podridão radicular em cultivos hidropônicos e o potencial de utilização do controle biológico da doença, os objetivos do presente trabalho foram (i) selecionar microrganismos residentes do manguezal como agentes de biocontrole da podridão radicular e promotores de crescimento em pepino hidropônico; (ii) avaliar o controle biológico da podridão radicular e a promoção de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03 em pimentão e alface cultivados em hidroponia; (iii) desenvolver uma formulação de Pseudomonas spp.. Em condições de casa de vegetação, Bacillus cereus AVIC-3-6, isolado de manguezal, protegeu as plantas de pepino do subdesenvolvimento causado pelo patógeno; Gordonia rubripertincta SO-3B-2 e Pseudomonas stutzeri MB-P3A-49, também isolados de manguezal, promoveram o crescimento de plantas de pepino não inoculadas com o patógeno. A adição de P. chlororaphis 63-28 e B. subtilis GB03 na solução nutritiva de pimentão cultivado em hidroponia e inoculado com P. aphanidermatum teve efeito positivo na supressão dos danos causados... (Resumop completo, clicar acesso eletrônico abaixo) / Abstract: Hydroponic production of vegetables and flowers is increasing in Brazil, and the production technology is improving. A major factor constraining crop productivity is root rot caused by Pythium spp. Root rot severity can be reduced by the application of appropriate antagonistic microbes into the hydroponic nutrient solution or root zone of the crops. When in the root zone beneficial microbes may suppress progress of the root rot and increase crop productivity. However some beneficial microbes are not well-adapted to hydroponic environments and do not survive well in plant nutrient solutions. Ecologically-adapted microbes that are effective against root rot are a key factor for successful root rot control in hydroponic crops. The need for effective biological agents that are adapted to hydroponic systems and appropriately formulated for commercial use prompted investigations with the following aims: i) to select bacterial strains from among isolates obtained from mangrove swamps for effectiveness in controlling Pythium root rot in hydroponic cucumber; ii) to evaluate Pseudomonas chlororaphis 63-28 and Bacillus subtilis GB03 for controlling root rot and promoting growth of hydroponic lettuce and pepper; and iii) to assess formulations of Pseudomonas spp. for long-term shelf life. Bacillus cereus AVIC -3-6 from a mangrove reduced stunting of hydroponic cucumbers associated with Pythium root rot. Gordonia rubripertincta SO-3B-2 and Pseudomonas stutzeri MB-3PA-49 from a mangrove increased growth of healthy cucumber plants. Application of Pseudomonas chlororaphis 63-28 and Bacillus subtilis GB03 into the nutrient solution of hydroponic pepper suppressed root rot and increase the plant growth. Among tested formulations of Pseudomonas chlororaphis 63-28, a formulation with coconut fibre of 80% moisture content had the longest shelf life (up to 32 weeks) when kept at at 3ºC. We conclude that a)... (Complete abstract click electronic access below) / Orientador: Wagner Bettiol / Coorientador: John Clifford Sutton / Banca: Antonio Carlos Maringoni / Banca: Edson Luiz Furtado / Banca: Marcelo Augusto Boechat Morandi / Doutor

Este estudo descreve a diversidade de actinobactérias isoladas da esponja marinha Aplysina fulva e o potencial destes microorganismos como produtores de metabólitos bioativos com propriedades fungicidas e herbicidas. Actinobactérias são prolíficas produtoras de compostos farmacologicamente importantes, pois cerca de 70% dos antibióticos naturalmente derivados que estão atualmente em uso clínico são produzidos por estes microorganismos. Entretanto este valor é ainda inexpressivo na indústria agrícola. Agroquímicos sintéticos ainda são dominantes no mercado apesar de estarem menos efetivos contra plantas daninhas e patógenos cada vez mais resistentes. Neste trabalho, um total de 21 actinobactérias foram isoladas com a utilização de meios seletivos. Análises filogenéticas baseadas no sequenciamento parcial do gene que codifica para o rRNA 16S mostrou que estes microorganismos pertencem a oito gêneros do filo Actinobacteria: Kocuria; Citricoccus; Terrabacter; Gordonia; Agrococcus; Tsukamurella; Brevibacterium e Streptomyces. Os extratos de todos os isolados foram testados para verificar a produção de metabólitos secundários com propriedades fungicidas contra os fungos fitopagênicos de importância agrícola: Pythium aphanidermatum; Phytophthora capsici e Magnaporthe grisea. O extrato bruto de 43% dos isolados mostrou atividade fungicida para ao menos um dos patógenos. O perfil químico do extrato dos isolados com bioatividade positiva foram similares mesmo entre gêneros diferentes. Os metabólitos do Streptomyces ASPSP 103 foram mais eficientes devido à forte inibição contra todos os patógenos testados. Portanto este isolado foi selecionado e testado para atividade herbicida por meio de screening que teve início com testes de atividade algicida contra a microalga Selenastrum capricornutum. Acreditamos que actinobactérias associadas a esponjas marinhas desempenham um papel de defesa química contra microalgas que possam obstruir os porócitos asfixiando o animal, e que estes compostos algicidas possivelmente tenham ação herbicida. Foi verificada atividade do extrato bruto do Streptomyces ASPSP 103 contra S. capricornutum, e a atividade herbicida pré-emergência com um efeito fraco em Lactuca sativa (dicotiledônea) e uma forte inibição em Agrostis stolonifera (monocotiledônea). A purificação do extrato bruto para isolamento do composto bioativo foi guiado por bioensaio contra Pythium aphanidermatum, um oomiceto de rápido crescimento e sensível aos metabólitos de ASPSP 103 previamente testados. Foi identificado o composto da classe butenolida com atividade herbicida préemergência contra Agrostis stolonifera (IC50 33.43 μg/mL). Este é o primeiro relato da atividade de butenolida para atividade herbicida. Estudos aprofundados em taxonomia mostraram que as características filogenéticas, morfológicas e químicas do isolado ASPSP 103 são consistentes com o gênero Streptomyces. Portanto devido algumas diferenças em parâmetros taxonômicos, ASPSP 103T foi proposto como linhagem tipo para uma nova espécie de Streptomyces, para qual o nome Streptomyces atlanticus sp. nov. foi sugerido. Estes resultados enfatizam o potencial de Streptomyces marinhos para produzir compostos bioativos com potencial de aplicação em agrobiotecnologia. / Actinobacteria are producers of important pharmacological compounds. About 70% of natural antibiotics are derived from these microorganisms. However, the use of natural compounds are still limited in the agricultural industry, even considering that synthetic pesticides are less effective against pathogens and weed plants. This study describes the diversity of actinobacteria associated with the marine sponge Aplysina fulva and their potential as producers of bioactive compounds with fungicidal and herbicidal properties. In this study, a total of 21 actinomycetes were isolated with the use of selective media. Phylogenetic analyzes based on partial sequencing of the gene encoding for 16S rRNA showed that these microorganisms belong to eight Actinobacteria genera, including Kocuria, Citricoccus, Terrabacter, Gordonia, Agrococcus, Tsukamurella, Brevibacterium and Streptomyces. The extracts of all isolates were tested for the production of secondary metabolites with fungicidal properties against the following phytopathogenic fungi: of Pythium aphanidermatum, Phytophthora capsici and Magnaporthe grisea. The crude extract of 43% of the isolates showed fungicidal activity for at least one of the pathogens. The chemical profiles of the actinobacteria extracts with positive bioactivity were similar even among different genus. The metabolites of Streptomyces ASPSP 103 were more efficient because of the strong inhibition against all tested pathogens. So, the isolate ASPSP 103 was selected and tested for herbicide activity through screening for algaecide activity towards microalgae Selenastrum capricornutum. We believe that actinobacteria associated with marine sponges play a role in chemical defense against algae that can obstruct the pores, choking the animal. These algaecides compounds possibly have herbicide action. Activity of the Streptomyces ASPSP 103 crude extract against S. capricornutum was observed. In addition, it was observed a weak pre-emergence herbicide activity on Lactuca sativa (dicot) and a strong inhibition in Agrostis stolonifera (monocot). The purification of the crude extract to isolate the bioactive compound was guided by bioassay against Pythium aphanidermatum, a fast growing oomycete and sensitive to metabolites from ASPSP 103 previously tested. The butenolide compound was identified with pre-emergence herbicidal activity against Agrostis stolonifera (IC50 33.43 μg/mL). This is the first report of butenolide activity with herbicide activity. Taxonomy studies showed that the phylogenetic, morphological and chemical characteristics of the isolated ASPSP 103 are consistent with the Streptomyces genus. Then, considering some differences in taxonomic parameters, ASPSP 103T was proposed as line type for a new species of Streptomyces, for which the name Streptomyces atlanticus sp. nov. was suggested. These results emphasize the potential of marine Streptomyces to produce bioactive compounds with potential biotechnological application in agricultural industry.

Este estudo descreve a diversidade de actinobactérias isoladas da esponja marinha Aplysina fulva e o potencial destes microorganismos como produtores de metabólitos bioativos com propriedades fungicidas e herbicidas. Actinobactérias são prolíficas produtoras de compostos farmacologicamente importantes, pois cerca de 70% dos antibióticos naturalmente derivados que estão atualmente em uso clínico são produzidos por estes microorganismos. Entretanto este valor é ainda inexpressivo na indústria agrícola. Agroquímicos sintéticos ainda são dominantes no mercado apesar de estarem menos efetivos contra plantas daninhas e patógenos cada vez mais resistentes. Neste trabalho, um total de 21 actinobactérias foram isoladas com a utilização de meios seletivos. Análises filogenéticas baseadas no sequenciamento parcial do gene que codifica para o rRNA 16S mostrou que estes microorganismos pertencem a oito gêneros do filo Actinobacteria: Kocuria; Citricoccus; Terrabacter; Gordonia; Agrococcus; Tsukamurella; Brevibacterium e Streptomyces. Os extratos de todos os isolados foram testados para verificar a produção de metabólitos secundários com propriedades fungicidas contra os fungos fitopagênicos de importância agrícola: Pythium aphanidermatum; Phytophthora capsici e Magnaporthe grisea. O extrato bruto de 43% dos isolados mostrou atividade fungicida para ao menos um dos patógenos. O perfil químico do extrato dos isolados com bioatividade positiva foram similares mesmo entre gêneros diferentes. Os metabólitos do Streptomyces ASPSP 103 foram mais eficientes devido à forte inibição contra todos os patógenos testados. Portanto este isolado foi selecionado e testado para atividade herbicida por meio de screening que teve início com testes de atividade algicida contra a microalga Selenastrum capricornutum. Acreditamos que actinobactérias associadas a esponjas marinhas desempenham um papel de defesa química contra microalgas que possam obstruir os porócitos asfixiando o animal, e que estes compostos algicidas possivelmente tenham ação herbicida. Foi verificada atividade do extrato bruto do Streptomyces ASPSP 103 contra S. capricornutum, e a atividade herbicida pré-emergência com um efeito fraco em Lactuca sativa (dicotiledônea) e uma forte inibição em Agrostis stolonifera (monocotiledônea). A purificação do extrato bruto para isolamento do composto bioativo foi guiado por bioensaio contra Pythium aphanidermatum, um oomiceto de rápido crescimento e sensível aos metabólitos de ASPSP 103 previamente testados. Foi identificado o composto da classe butenolida com atividade herbicida préemergência contra Agrostis stolonifera (IC50 33.43 μg/mL). Este é o primeiro relato da atividade de butenolida para atividade herbicida. Estudos aprofundados em taxonomia mostraram que as características filogenéticas, morfológicas e químicas do isolado ASPSP 103 são consistentes com o gênero Streptomyces. Portanto devido algumas diferenças em parâmetros taxonômicos, ASPSP 103T foi proposto como linhagem tipo para uma nova espécie de Streptomyces, para qual o nome Streptomyces atlanticus sp. nov. foi sugerido. Estes resultados enfatizam o potencial de Streptomyces marinhos para produzir compostos bioativos com potencial de aplicação em agrobiotecnologia. / Actinobacteria are producers of important pharmacological compounds. About 70% of natural antibiotics are derived from these microorganisms. However, the use of natural compounds are still limited in the agricultural industry, even considering that synthetic pesticides are less effective against pathogens and weed plants. This study describes the diversity of actinobacteria associated with the marine sponge Aplysina fulva and their potential as producers of bioactive compounds with fungicidal and herbicidal properties. In this study, a total of 21 actinomycetes were isolated with the use of selective media. Phylogenetic analyzes based on partial sequencing of the gene encoding for 16S rRNA showed that these microorganisms belong to eight Actinobacteria genera, including Kocuria, Citricoccus, Terrabacter, Gordonia, Agrococcus, Tsukamurella, Brevibacterium and Streptomyces. The extracts of all isolates were tested for the production of secondary metabolites with fungicidal properties against the following phytopathogenic fungi: of Pythium aphanidermatum, Phytophthora capsici and Magnaporthe grisea. The crude extract of 43% of the isolates showed fungicidal activity for at least one of the pathogens. The chemical profiles of the actinobacteria extracts with positive bioactivity were similar even among different genus. The metabolites of Streptomyces ASPSP 103 were more efficient because of the strong inhibition against all tested pathogens. So, the isolate ASPSP 103 was selected and tested for herbicide activity through screening for algaecide activity towards microalgae Selenastrum capricornutum. We believe that actinobacteria associated with marine sponges play a role in chemical defense against algae that can obstruct the pores, choking the animal. These algaecides compounds possibly have herbicide action. Activity of the Streptomyces ASPSP 103 crude extract against S. capricornutum was observed. In addition, it was observed a weak pre-emergence herbicide activity on Lactuca sativa (dicot) and a strong inhibition in Agrostis stolonifera (monocot). The purification of the crude extract to isolate the bioactive compound was guided by bioassay against Pythium aphanidermatum, a fast growing oomycete and sensitive to metabolites from ASPSP 103 previously tested. The butenolide compound was identified with pre-emergence herbicidal activity against Agrostis stolonifera (IC50 33.43 μg/mL). This is the first report of butenolide activity with herbicide activity. Taxonomy studies showed that the phylogenetic, morphological and chemical characteristics of the isolated ASPSP 103 are consistent with the Streptomyces genus. Then, considering some differences in taxonomic parameters, ASPSP 103T was proposed as line type for a new species of Streptomyces, for which the name Streptomyces atlanticus sp. nov. was suggested. These results emphasize the potential of marine Streptomyces to produce bioactive compounds with potential biotechnological application in agricultural industry.

Pythium root rot caused by Pythium aphanidermatum, a destructive disease of sweet pepper and other hydroponic crops, is characterized by root browning (necrosis) and reduces growth of roots and shoots. Serious losses in crop productivity are common, in part for lack of adequate control measures. Severe root rot has been previously associated with episodes of high temperature, but whether this is due to high temperature effects on the host, the pathogen, or their interaction remains unclear. To clarify these relationships, and to provide a basis for predicting rapid increases in root rot, quantitative experiments were conducted to determine how episodes of high root-zone temperature are associated with root browning. Pepper plants were grown separately in hydroponic units containing aerated nutrient solution positioned in temperature-controlled water baths. The root zone temperature was 23°C except during high temperature treatments. Browning developed progressively earlier in roots that were maintained at 33°C for 9 to 144 h immediately before they were inoculated with zoospores of P. aphanidermatum, and in all instances earlier than in control plants maintained continuously at 23°C. The data demonstrated unequivocally that high root-zone temperature can predispose pepper plants to Pythium root rot. Browning also developed earlier when root inoculation with P. aphanidermatum was delayed as long as 216 h following exposure at 33°C for 72 h, indicating that predisposition of the host by high temperature episodes can persist for at least 9 days. The ability of Pseudomonas chlororaphis strain 63-28 to suppress Pythium root rot and promote plant growth was investigated in pepper plants grown in the hydroponic units and predisposed to the disease, i.e. plants were predisposed to high temperature (33°C for 72 h ending at 3 days before inoculation) or not predisposed (constant 23°C). When P. chlororaphis was applied in the nutrient solution at a final density of 107 CFU mL-1 7 days before the high temperature episode, the agent delayed root browning, re-mediated predisposition to root rot, and increased growth of plants that were and were not inoculated with P. aphanidermatum. It is concluded that high temperature predisposed pepper seedlings to root rot and that strain 63-28 has substantial potential for managing root rot regardless of predisposition by high temperature.

Cucumber root rot caused by Pythium aphanidermatum can be suppressed by introduced plant growth-promoting rhizobacteria (PGPR). Preliminary experiments clarified that this root disease could be suppressed by strains of Pseudomonas aureofaciens, P. corrugata, and P. fluorescens. To determine whether the mechanism was a systemic resistance induced by PGPR, a split root technique was employed on greenhouse cucumbers grown in soilless substrates. On the split roots, bacteria which were introduced into one side of the root were completely separated from pathogen challenged-inoculated roots-on the other side of the roots. Results from the series of experiments conducted with this design demonstrated that (i) the resistance against root rot induced by PGPR was systemic, (ii) germination of P. aphanidermatum zoospores was reduced in extracts from bacterized roots compared to non-treated control, and (iii) spread of Pythium mycelia was delayed and zoospore germination was inhibited on the distant induced root, compared to the non-bacterized control. Furthermore, enzyme analysis indicated that phenylalanine ammonia lyase, peroxidase and polyphenoloxidase increased on cucumber roots two days after they were bacterized with Pseudomonas strains 13 or 63--28. When the bacterized roots were challenged with P. aphanidermatum, these plant defense enzymes increased as the symptoms appeared, but this accumulation of enzymes was not any higher on roots induced with each of the Pseudomonas strains compared to the Pythium inoculated control. This enzyme stimulation was also systemically induced by PGPR or P. aphanidermatum on cucumber roots. The patterns of iso-peroxidase induced with the PGPR and P. aphanidermatum treatments were different. High levels of salicylic acid (SA) accumulated in bacteria-induced roots, as well as in pathogen-infected roots, which suggests that SA may be associated with cucumber resistance response. But exogenous application of SA did not induce any systemi

No description available.

New Jersey, Georgia, and the Eastern Shore of Virginia (ESV) are important snap bean (Phaseolus vulgaris L.) growing regions, but profitability is threatened by Pythium blight. Causal agents of Pythium blight on snap bean were identified using morphological characterization and sequence analysis of the rDNA-internal transcribed spacer (ITS) regions of 100 isolates. Most isolates were Pythium aphanidermatum (Edson) Fitzp. (53%), and also included Pythium deliense Meurs (31%; all from Georgia), Pythium ultimum Trow (12%), Pythium myriotylum Drechsler (2%), Pythium catenulatum Matthews (1%), and unknown Pythium sp. (1%). To our knowledge, this is the first report of P. deliense in Georgia and on common bean and squash (Cucurbita pepo L.); as well as the first report of P. catenulatum on lima bean (Phaseolus lunatus L.) and in New Jersey. Fungicide labeling and cultivar selection for Pythium blight management is hindered by difficulties associated with conducting successful trials, because the disease occurs sporadically and clustered in the field. Three P. aphanidermatum-infested inoculum substrates were evaluated at three concentrations. The vermiculite/V8 juice (5:3 weight to volume) inoculum (10,000 ppg/0.3 m) consistently caused at least 50% disease in 3 field trials. Sensitivity of the Pythium blight pathogens was determined in vitro against five fungicides. Twenty-two Pythium isolates representing P. aphanidermatum, P. deliense, P. ultimum, and P. myriotylum were inoculated to media amended with each active ingredient at 0, 100μg/ml, the concentration equivalent to the field labeled rate if applied on succulent beans at 187 L/ha, and the equivalent if applied at 374 L/ha. All isolates were completely sensitive (100% growth reduction, or GR) to all active ingredients at the labeled rates, except azoxystrobin. At 100μg/ml azoxystrobin, one P. deliense isolate had 8.9% GR. All isolates had 100% GR to copper hydroxide at 100μg/ml, and the lowest GR on mefenoxam-amended medium was 91.9%. At 100μg/ml cyazofamid, all P. deliense isolates were completely sensitive and variation was observed in P. aphanidermatum isolates. At 100μg/ml potassium phosphite, significant GR similarities were recorded within isolates of the same species, and less than 50% GR was observed in all P. deliense isolates. / Ph. D.