RESUMO

O uso de extratos e óleos essenciais de plantas medicinais tem sido amplamente estudado no controle de doenças de plantas. O objetivo da realização do presente trabalho foi avaliar o efeito de extratos de Ruta graveolens L., Mentha x villosa, Calendula officinalis L., Momordica charantia L., Symphytum officinale L., Ageratum conyzoides L. e Ricinus comunis L., nas concentrações de 0, 250, 500, 1000, 2000, 5000 e 10000 mg L-1, sobre a inibição do crescimento micelial de Cercospora calendulae Sacc. in vitro. Os extratos foram obtidos por infusão. O experimento foi desenvolvido no Laboratório de Fitopatologia da FCA/UFGD, estado de Mato Grosso do Sul, em delineamento inteiramente casualizado, esquema fatorial 7 extratos x 7 concentrações, com seis repetições. Foi detectado efeito dos extratos e suas concentrações sobre o crescimento do fungo, sendo a interação significativa. Os extratos de calêndula, arruda, hortelã e melão de São Caetano, nas maiores concentrações resultaram em maiores porcentagens de inibição, próximas de 100%, 30%, 35% e 40%, respectivamente, a 10000 mg L-1.

This study was carried out to investigate the effects of the extracts of Ruta graveolens L., Mentha x villosa, Calendula officinalis L., Momordica charantia L., Symphytum officinale L., Ageratum conyzoides L. and Ricinus comunis L., in the concentrations of 0, 250, 500, 1000, 2000, 5000 and 10000 mg L-1, on the inhibition of the mycelial growth of in vitro Cercospora calendulae Sacc. The extracts were obtained by infusion. The experiment was performed at the Laboratório de Fitopatologia - FCA/UFGD, in the Brazilian State of Mato Grosso do Sul. The experimental design was totally randomized, with a factorial arrangement of 7 extracts x 7 concentrations, with six repetitions. We detected the effect of the extracts and their concentrations on the growth of the fungus, with a significant interaction between the factor extracts and the concentration. Calendula officinalis L., Ruta graveolens L., Mentha x villosa and Momordica charantia L. extracts in higher concentration resulted in higher inhibition percentages in the order of 100%, 30%, 35% and 40%, respectively.

Assuntos

RESUMO

Herbicides are commonly used in agriculture for weed control. Since they are applied in the field, target plants and other organisms are exposed to their action. This exposure may have distinct effects on crop plants, either by predisposing them to plant pathogens or affecting the pathogen's ability to cause disease. The effect of herbicides on the development of disease usually results from direct action on the pathogen and indirectly by the activation of plant response. The objective of this study was evaluate the effect of herbicides, clorimuron-ethyl, fomesafen + mineral oil, cletodim + fenoxaprop-P-ethyl, lactofen on urediniospores of Phakopsora pachyrhizi. Germination and germ tube length were evaluated at the exposure times of 1, 2, 4, 8 and 24 h. All herbicides inhibited urediniospore germination. Chlorimuron-ethyl, cletodim + fenoxaprop-P-ethyl, fomesafen + mineral oil, glyphosate and lactofen reduced germ tube length of urediniospores, indicating that these products were toxic to the spores of P. pachyrhizi.

Herbicidas são bastante utilizados na agricultura para controle de plantas daninhas. Por serem aplicados sobre as plantas, além de exercerem ação sobre o organismo alvo, podem influenciar outros processos ou a interação da planta, predispondo ou reduzindo a suscetibilidade a doenças. O efeito dos herbicidas no desenvolvimento de doenças geralmente resulta da ação direta no patógeno e indireta pela ativação de resposta da planta. Objetivou-se neste estudo avaliar in vitro o efeito dos herbicidas cletodim + fenoxaprop-P-etílico, clorimurom-etílico, fomesafem + óleo mineral, lactofem e glyphosate sobre uredósporos de Phakopsora pachyrhizi. A germinação e o comprimento do tubo germinativo dos uredósporos foram avaliados em 1, 2, 4, 8 e 24h de exposição aos herbicidas. Todos os herbicidas inibiram a germinação dos uredósporos. Tubos germinativos emitidos por uredósporos expostos a cletodim + fenoxaprope-P-etílico, clorimurom-etílico, lactofem e glyphosate apresentaram menores comprimentos, indicando ação tóxica dos herbicidas.

RESUMO

Two experiments were conducted at the Federal University of Grande Dourados, in order to evaluate the efficiency of fungicides, Carboxin + Thiram and Carbendazin + Thiram at different doses on seed health and its effect on seedling vigor. The fungicides, Carboxin + Thiram was evaluated at doses of 350, 450 and 550 mL and Carbendazin + Thiram at doses of 200, 300 and 400 mL, the respective doses for 100 kg of seeds. The experimental design for both trials was completely randomized design with 7 treatments, 10 repetitions for the test of sanity and 5 for analysis of the vigor. We analyzed the percentage incidence of fungi in seed and seedling vigor, through a field emergence, index of emergence speed and plant height. We report the incidence of Aspergillus sp., Penicillium sp., Fusarium sp. Phomopsis sp. and Rhizopus sp., and Carboxin + Thiram at a dose of 550 ml, the treatment most effective in controlling pathogens. For field emergence, both fungicides were effective, providing increases ranging from 48.9 to 97.4% of emergency. The index of emergence speed was favored by treatments with Carboxin + Thiram at a dose of 550 mL and Carbendazin + Thiram at doses of 300 and 400 ml. It was found that Fusarium sp. was the pathogen with the highest percentage of incidence on seeds, however, the highest correlation with the low emergence were observed by the presence of Penicillium sp. and Phomopsis sp.

Foram desenvolvidos dois experimentos na Universidade Federal da Grande Dourados, com o objetivo de avaliar a eficiência dos fungicidas, Carboxin + Thiram e Carbendazin + Thiram, em diferentes doses, na sanidade de sementes e seu efeito sobre o vigor de plântulas. Os fungicidas, Carboxin + Thiram foi avaliado nas doses de 350, 450 e 550 mL e Carbendazin + Thiram nas doses de 200, 300 e 400 mL, sendo as respectivas doses para 100 kg de sementes. O delineamento experimental para ambos os ensaios foi inteiramente casualizado com 7 tratamentos, 10 repetições para o ensaio de sanidade e 5 repetições para análise do vigor. Analisaram-se a porcentagem de incidência de fungos nas sementes e o vigor de plântulas, por meio da emergência a campo, índice de velocidade de emergência e altura de plantas. Relata-se a incidência de Aspergillus sp., Penicillium sp., Fusarium sp., Phomopsis sp. e Rhizopus sp., sendo Carboxin + Thiram na dose de 550 mL, o tratamento mais eficiente no controle dos patógenos. Quanto à emergência a campo, ambos os fungicidas foram eficientes, proporcionando aumentos que variaram de 48,9 a 97,4% de emergência. O índice de velocidade de emergência foi favorecido pelos tratamentos com Carboxin + Thiram na dose de 550 mL e Carbendazin + Thiram nas doses de 300 e 400 ml. Constatou-se que Fusarium sp. foi o patógeno com maior percentual de incidência sobre as sementes, todavia, as maiores correlações com a baixa emergência foram observadas pela presença dos fungos Penicillium sp. e Phomopsis sp.

RESUMO

Foram desenvolvidos dois experimentos na Universidade Federal da Grande Dourados, com o objetivo de avaliar a eficiência dos fungicidas, Carboxin + Thiram e Carbendazin + Thiram, em diferentes doses, na sanidade de sementes e seu efeito sobre o vigor de plântulas. Os fungicidas, Carboxin + Thiram foi avaliado nas doses de 350, 450 e 550 mL e Carbendazin + Thiram nas doses de 200, 300 e 400 mL, sendo as respectivas doses para 100 kg de sementes. O delineamento experimental para ambos os ensaios foi inteiramente casualizado com 7 tratamentos, 10 repetições para o ensaio de sanidade e 5 repetições para análise do vigor. Analisaram-se a porcentagem de incidência de fungos nas sementes e o vigor de plântulas, por meio da emergência a campo, índice de velocidade de emergência e altura de plantas. Relata-se a incidência de Aspergillus sp., Penicillium sp., Fusariumsp., Phomopsis sp. e Rhizopus sp., sendo Carboxin + Thiram na dose de 550 mL, o tratamento mais eficiente no controle dos patógenos. Quanto à emergência a campo, ambos os fungicidas foram eficientes, proporcionando aumentos que variaram de 48,9 a 97,4% de emergência. O índice de velocidade de emergência foi favorecido pelos tratamentos com Carboxin + Thiram na dose de 550 mL e Carbendazin + Thiram nas doses de 300 e 400 ml. Constatou-se que Fusarium sp. foi o patógeno com maior percentual de incidência sobre as sementes, todavia, as maiores correlações com a baixa emergência foram observadas pela presença dos fungos Penicillium sp. e Phomopsis sp.

SANITARY AND PHYSIOLOGICAL QUALITY SEED OF JATROPHA TREATED WITH FUNGICIDES. Two experiments were conducted at the Federal University of Grande Dourados, in order to evaluate the efficiency of fungicides, Carboxin + Thiram and Carbendazin + Thiram at different doses on seed health and its effect on seedling vigor. The fungicides, Carboxin + Thiram was evaluated at doses of 350, 450 and 550 mL and Carbendazin + Thiram at doses of 200, 300 and 400 mL, the respective doses for 100 kg of seeds. The experimental design for both trials was completely randomized design with 7 treatments, 10 repetitions for the test of sanity and 5 for analysis of the vigor. We analyzed the percentage incidence of fungi in seed and seedling vigor, through a field emergence, index of emergence speed and plant height. We report the incidence of Aspergillus sp., Penicillium sp., Fusarium sp. Phomopsis sp. and Rhizopus sp., and Carboxin + Thiram at a dose of 550 ml, the treatment most effective in controlling pathogens. For field emergence, both fungicides were effective, providing increases ranging from 48.9 to 97.4% of emergency. The index of emergence speed was favored by treatments with Carboxin + Thiram at a dose of 550 mL and Carbendazin + Thiram at doses of 300 and 400 ml. It was found that Fusarium sp. was the pathogen with the highest percentage of incidence on seeds, however, the highest correlation with the low emergence were observed by the presence of Penicillium sp. and Phomopsis sp.

Assuntos

RESUMO

Herbicidas são bastante utilizados na agricultura para controle de plantas daninhas. Por serem aplicados sobre as plantas, além de exercerem ação sobre o organismo alvo, podem influenciar outros processos ou a interação da planta, predispondo ou reduzindo a suscetibilidade a doen-ças. O efeito dos herbicidas no desenvolvimento de doenças geralmente resulta da ação direta no patógeno e indireta pela ativação de resposta da planta. Objetivou-se neste estudo avaliar in vitroo efeito dos herbicidas cletodim + fenoxaprop-P-etílico, clorimurom-etílico, fomesafem + óleo mineral, lactofem e glyphosate sobre uredósporos de Phakopsora pachyrhizi. A germinação e o comprimento do tubo germinativo dos uredósporos foram avaliados em 1, 2, 4, 8 e 24h de exposição aos herbicidas. Todos os herbicidas inibiram a germinação dos uredósporos. Tubos germinativos emitidos por uredósporos expostos a cletodim + fenoxaprope-P-etílico, clorimurom-etílico, lactofem e glyphosate apresentaram menores comprimentos, indicando ação tóxica dos herbicidas.

THE EFFECT OF HERBICIDES ON THE GERMINATION OF UREDINIOSPORES OF PHAKOPSORA PACHYRHIZI SYD. & P. SYD. Herbicides are commonly used in agriculture for weed control. Since they are applied in the field, target plants and other organisms are exposed to their action. This exposure may have distinct effects on crop plants, either by predisposing them to plant pathogens or affecting the pathogen’s ability to cause disease. The effect of herbicides on the development of disease usually results from direct action on the pathogen and indirectly by the activation of plant response. The objective of this study was evaluate the effect of herbicides, clorimuron-ethyl, fomesafen + mineral oil, cletodim + fenoxaprop-P-ethyl, lactofen on urediniospores of Phakopsora pachyrhizi. Germination and germ tube length were evaluated at the exposure times of 1, 2, 4, 8 and 24 h. All herbicides inhibited urediniospore germination. Chlorimuron-ethyl, cletodim + fenoxaprop-P-ethyl, fomesafen + mineral oil, glyphosate and lactofen reduced germ tube length of urediniospores, indicating that these products were toxic to the spores of P. pachyrhizi.

Assuntos

RESUMO

Herbicidas são bastante utilizados na agricultura para controle de plantas daninhas. Por serem aplicados sobre as plantas, além de exercerem ação sobre o organismo alvo, podem influenciar outros processos ou a interação da planta, predispondo ou reduzindo a suscetibilidade a doen-ças. O efeito dos herbicidas no desenvolvimento de doenças geralmente resulta da ação direta no patógeno e indireta pela ativação de resposta da planta. Objetivou-se neste estudo avaliar in vitroo efeito dos herbicidas cletodim + fenoxaprop-P-etílico, clorimurom-etílico, fomesafem + óleo mineral, lactofem e glyphosate sobre uredósporos de Phakopsora pachyrhizi. A germinação e o comprimento do tubo germinativo dos uredósporos foram avaliados em 1, 2, 4, 8 e 24h de exposição aos herbicidas. Todos os herbicidas inibiram a germinação dos uredósporos. Tubos germinativos emitidos por uredósporos expostos a cletodim + fenoxaprope-P-etílico, clorimurom-etílico, lactofem e glyphosate apresentaram menores comprimentos, indicando ação tóxica dos herbicidas. (AU)

THE EFFECT OF HERBICIDES ON THE GERMINATION OF UREDINIOSPORES OF PHAKOPSORA PACHYRHIZI SYD. & P. SYD. Herbicides are commonly used in agriculture for weed control. Since they are applied in the field, target plants and other organisms are exposed to their action. This exposure may have distinct effects on crop plants, either by predisposing them to plant pathogens or affecting the pathogens ability to cause disease. The effect of herbicides on the development of disease usually results from direct action on the pathogen and indirectly by the activation of plant response. The objective of this study was evaluate the effect of herbicides, clorimuron-ethyl, fomesafen + mineral oil, cletodim + fenoxaprop-P-ethyl, lactofen on urediniospores of Phakopsora pachyrhizi. Germination and germ tube length were evaluated at the exposure times of 1, 2, 4, 8 and 24 h. All herbicides inhibited urediniospore germination. Chlorimuron-ethyl, cletodim + fenoxaprop-P-ethyl, fomesafen + mineral oil, glyphosate and lactofen reduced germ tube length of urediniospores, indicating that these products were toxic to the spores of P. pachyrhizi. (AU)

Assuntos

RESUMO

Foram desenvolvidos dois experimentos na Universidade Federal da Grande Dourados, com o objetivo de avaliar a eficiência dos fungicidas, Carboxin + Thiram e Carbendazin + Thiram, em diferentes doses, na sanidade de sementes e seu efeito sobre o vigor de plântulas. Os fungicidas, Carboxin + Thiram foi avaliado nas doses de 350, 450 e 550 mL e Carbendazin + Thiram nas doses de 200, 300 e 400 mL, sendo as respectivas doses para 100 kg de sementes. O delineamento experimental para ambos os ensaios foi inteiramente casualizado com 7 tratamentos, 10 repetições para o ensaio de sanidade e 5 repetições para análise do vigor. Analisaram-se a porcentagem de incidência de fungos nas sementes e o vigor de plântulas, por meio da emergência a campo, índice de velocidade de emergência e altura de plantas. Relata-se a incidência de Aspergillus sp., Penicillium sp., Fusariumsp., Phomopsis sp. e Rhizopus sp., sendo Carboxin + Thiram na dose de 550 mL, o tratamento mais eficiente no controle dos patógenos. Quanto à emergência a campo, ambos os fungicidas foram eficientes, proporcionando aumentos que variaram de 48,9 a 97,4% de emergência. O índice de velocidade de emergência foi favorecido pelos tratamentos com Carboxin + Thiram na dose de 550 mL e Carbendazin + Thiram nas doses de 300 e 400 ml. Constatou-se que Fusarium sp. foi o patógeno com maior percentual de incidência sobre as sementes, todavia, as maiores correlações com a baixa emergência foram observadas pela presença dos fungos Penicillium sp. e Phomopsis sp. (AU)

SANITARY AND PHYSIOLOGICAL QUALITY SEED OF JATROPHA TREATED WITH FUNGICIDES. Two experiments were conducted at the Federal University of Grande Dourados, in order to evaluate the efficiency of fungicides, Carboxin + Thiram and Carbendazin + Thiram at different doses on seed health and its effect on seedling vigor. The fungicides, Carboxin + Thiram was evaluated at doses of 350, 450 and 550 mL and Carbendazin + Thiram at doses of 200, 300 and 400 mL, the respective doses for 100 kg of seeds. The experimental design for both trials was completely randomized design with 7 treatments, 10 repetitions for the test of sanity and 5 for analysis of the vigor. We analyzed the percentage incidence of fungi in seed and seedling vigor, through a field emergence, index of emergence speed and plant height. We report the incidence of Aspergillus sp., Penicillium sp., Fusarium sp. Phomopsis sp. and Rhizopus sp., and Carboxin + Thiram at a dose of 550 ml, the treatment most effective in controlling pathogens. For field emergence, both fungicides were effective, providing increases ranging from 48.9 to 97.4% of emergency. The index of emergence speed was favored by treatments with Carboxin + Thiram at a dose of 550 mL and Carbendazin + Thiram at doses of 300 and 400 ml. It was found that Fusarium sp. was the pathogen with the highest percentage of incidence on seeds, however, the highest correlation with the low emergence were observed by the presence of Penicillium sp. and Phomopsis sp. (AU)

Assuntos

RESUMO

Com o objetivo de avaliar in vitro o efeito de diferentes concentrações de extratos vegetais sobre o crescimento de Cercospora kikuchii, Fusarium solani, Colletotrichum sp. e Phomopsis sp., foram conduzidos quatro bioensaios experimentais, no Laboratório de Fitopatologia da Universidade Federal da Grande Dourados. Foi adotado o delineamento inteiramente casualizado em arranjo fatorial 3 x 6, com 8 repetições para cada bioensaio. Foram utilizados extratos aquosos de alho, canela e cravo-da-índia, nas concentrações de 0; 0,5; 1; 5; 10 e 20%. Para obtenção dos extratos foram coletadas 30 g do material vegetal e trituradas em 120 mL de água destilada. Os extratos foram filtrados em papel Wathman nº 1 e incorporados ao meio BDA, de modo a obter as concentrações desejadas. Posteriormente, a solução foi vertida em placas de Petri, onde foram transferidos discos de micélio do patógeno, de 0,3 cm de diâmetro. Em seguida, as placas foram incubadas a 25º C, com fotoperíodo de 12 horas. Foi analisado o crescimento micelial da colônia fúngica. Os resultados revelaram que o efeito do extrato aquoso de canela para todos os patógenos estudados, e do extrato de alho para F. solani, Colletotrichum sp. e Phomopsis sp. foi dependente das concentrações utilizadas, constatando-se maior atividade antifúngica com o aumento das concentrações. Verificou-se com o uso do extrato de cravo-da-índia maior eficácia no controle dos fitopatógenos testados, sendo observada supressão sobre o crescimento de Colletotrichum sp., Cercospora kikuchii, F. solani e de Phomopsis sp. a partir das concentrações de 7,4, 7,5, 8,9 e 7,0%, respectivamente. O extrato aquoso de alho, na concentração de 9,7%, apresentou efetivo controle apenas sobre C. kikuchii.

In order to evaluate the in vitro effect of different concentrations of plant extracts on the growth of Cercospora kikuchii, Fusarium solani, Colletotrichum sp. and Phomopsis sp., 4 bioassays experiments were conducted at the Plant Pathology Laboratory of the Federal University of Grande Dourados, Brazil. The experimental design was a completely randomized design in a 3 x 6 factorial arrangement, with 8 replicates for each bioassay. Aqueous extracts of garlic, cinnamon and clove were evaluated in concentrations of 0, 0.5, 1, 5, 10 and 20%. Extracts were obtained through maceration of 30 g of plant material in 120 mL of distilled water. The extracts were filtered in grade-1 Whatman paper and incorporated into PDA medium to obtain the desired concentrations. Subsequently, the solution was poured into Petri dishes, and then 3 mm-diameter-PDA plugs with pathogen mycelium were transferred to the center of the PDA + plant extract Petri dish. Plates were incubated at 25° C with a 12-h-day photoperiod. Fungal growth was performed daily by measuring the colony diameter. The results showed that the effect of aqueous extract of cinnamon for all pathogens studied, and garlic extract for F. solani, Colletotrichum sp. and Phomopsis sp., was dependent on the concentrations used, noting a higher antifungal activity with increased concentrations used. Clove extract presented the greatest effectiveness for the control of the plant pathogens tested, with observed suppression on the growth of Colletotrichum sp. C. kikuchii, F. solani and Phomopsis sp. at the concentrations 7.4, 7.5, 8.9 and 7.0%, respectively. The aqueous extract of garlic at a concentration of 9.7% presented effective control only for C. kikuchii.

Assuntos

RESUMO

ABSTRACT In order to evaluate the in vitro effect of different concentrations of plant extracts on the growth of Cercospora kikuchii. Fusarium solani. Colletotrichum sp. and Phomopsis sp., 4 bioassays experiments were conducted at the Plant Pathology Laboratory of the Federal University of Grande Dourados, Brazil. The experimental design was a completely randomized design in a 3 x 6 factorial arrangement, with 8 replicates for each bioassay. Aqueous extracts of garlic, cinnamon and clove were evaluated in concentrations of 0, 0.5, 1, 5, 10 and 20%. Extracts were obtained through maceration of 30 g of plant material in 120 mL of distilled water. The extracts were filtered in grade-1 Whatman paper and incorporated into PDA medium to obtain the desired concentrations. Subsequently, the solution was poured into Petri dishes, and then 3 mm-diameter-PDA plugs with pathogen mycelium were transferred to the center of the PDA + plant extract Petri dish. Plates were incubated at 25° C with a 12-h-day photoperiod. Fungal growth was performed daily by measuring the colony diameter. The results showed that the effect of aqueous extract of cinnamon for all pathogens studied, and garlic extract for F. solani. Colletotrichum sp. and Phomopsis sp., was dependent on the concentrations used, noting a higher antifungal activity with increased concentrations used. Clove extract presented the greatest effectiveness for the control of the plant pathogens tested, with observed suppression on the growth of Colletotrichum sp. C. kikuchii. F. solani and Phomopsis sp. at the concentrations 7.4, 7.5, 8.9 and 7.0%, respectively. The aqueous extract of garlic at a concentration of 9.7% presented effective control only for C. kikuchii.

RESUMO Com o objetivo de avaliar in vitro o efeito de diferentes concentrações de extratos vegetais sobre o crescimento de Cercospora kikuchii. Fusarium solani. Colletotrichum sp. e Phomopsis sp., foram conduzidos quatro bioensaios experimentais, no Laboratório de Fitopatologia da Universidade Federal da Grande Dourados. Foi adotado o delineamento inteiramente casualizado em arranjo fatorial 3 x 6, com 8 repetições para cada bioensaio. Foram utilizados extratos aquosos de alho, canela e cravo-da-índia, nas concentrações de 0; 0,5; 1; 5; 10 e 20%. Para obtenção dos extratos foram coletadas 30 g do material vegetal e trituradas em 120 mL de água destilada. Os extratos foram filtrados em papel Wathman nº 1 e incorporados ao meio BDA, de modo a obter as concentrações desejadas. Posteriormente, a solução foi vertida em placas de Petri, onde foram transferidos discos de micélio do patógeno, de 0,3 cm de diâmetro. Em seguida, as placas foram incubadas a 25º C, com fotoperíodo de 12 horas. Foi analisado o crescimento micelial da colônia fúngica. Os resultados revelaram que o efeito do extrato aquoso de canela para todos os patógenos estudados, e do extrato de alho para F. solani. Colletotrichum sp. e Phomopsis sp. foi dependente das concentrações utilizadas, constatando-se maior atividade antifúngica com o aumento das concentrações. Verificou-se com o uso do extrato de cravo-da-índia maior eficácia no controle dos fitopatógenos testados, sendo observada supressão sobre o crescimento de Colletotrichum sp., Cercospora kikuchii, .. solani e de Phomopsis sp. a partir das concentrações de 7,4, 7,5, 8,9 e 7,0%, respectivamente. O extrato aquoso de alho, na concentração de 9,7%, apresentou efetivo controle apenas sobre C. kikuchii.

RESUMO

Foram conduzidos no Laboratório de Fitopatologia da Universidade Federal da Grande Dourados três experimentos com o objetivo de avaliar in vitro a atividade antifúngica dos extratos aquosos de alho, canela e cravo-da-índia, submetidos a diferentes processos de desinfestação e/ou esterilização sobre o desenvolvimento de Fusarium solani. O delineamento experimental utilizado para cada ensaio foi inteiramente casualizado, com 5 tratamentos e 8 repetições. Utilizaram-se os extratos aquosos na concentração de 20 por cento, submetidos às metodologias de filtragem (FI), banho maria a 65°C (BM), autoclavagem a 100ºC (AT1), autoclavagem a 120ºC (AT2) e a testemunha (somente BDA). Posteriormente os extratos foram incorporados em meio BDA, acondicionados em placas de Petri, onde foram transferidos discos de micélio de F. solani medindo 0,3 cm de diâmetro. Após, as placas foram incubadas a 25ºC, com fotoperíodo de 12 horas. Os tratamentos foram analisados em relação ao crescimento micelial da colônia, a porcentagem de inibição e a taxa de crescimento de F. solani. Foi observado em todos os ensaios maior crescimento do fungo na testemunha, evidenciando o potencial antifúngico dos extratos. Foi observada influência da metodologia de esterilização sobre a eficiência dos extratos de alho e canela. Para o alho a FI proporcionou os melhores resultados, enquanto que para o extrato de canela não houve diferenças entre as metodologias FI, BM e AT1. As diferentes metodologias utilizadas não interferiram na eficiência do extrato aquoso de cravo-da-índia.

Three experiments were conducted in the Laboratory of Phytopathology of Federal University of Grande Dourados, Mato Grosso do Sul State, Brazil, to evaluate in vitro the antifungal activity of aqueous extracts of garlic, cinnamon and clove subjected to different processes of disinfection and/or sterilization against the development of Fusarium solani. The experimental design for each trial was completely randomized, with 5 treatments and 8 replicates. Aqueous extracts at a concentration of 20 percent were subjected to the methods of filtering (FI), water bath at 65ºC (WB), autoclaving at 100ºC (AT1), autoclaving at 120ºC (AT2) and control treatment (PDA alone). Subsequently, the extracts were incorporated into PDA medium, added to Petri dishes, to where F. solani mycelium discs of 0.3cm diameter were transferred. Then, the plates were incubated at 25ºC with 12-h photoperiod. The treatments were analyzed as to mycelial growth of the colony, percentage of inhibition and growth rate of F. solani. Increased fungal growth was observed for the control treatment, demonstrating the antifungal potential of the extracts. The sterilization method influenced the efficiency of garlic and cinnamon extracts. For garlic, FI led to the best results, whereas for cinnamon extract there were no differences among the methodologies FI, WB and AT1. The different methods used did not interfere with the efficiency of the aqueous extract of clove.

Assuntos

RESUMO

Two soybean cultivars, one conventional and a glyphosate-tolerant (transgenic), were submitted to the water stress and the chlorophyll a fluorescence induced by UV light was monitored daily during 16 days. In this work, 40 pots in total, 20 per cultivar were used in the investigation. Each cultivar was divided in two groups, the control group and the group submitted to the water stress. The stress response of the cultivars was monitored by red to far-red fluorescence ratio. The data indicate that the water stress induced the earliest changes on the fluorescence ratio and chlorophyll content for the conventional cultivar. In addition, a comparative analysis of the fluorescence ratios of the cultivars reveals that conventional plants have higher chlorophyll content than transgenic ones. This result might be useful in the development of methodologies able to distinguish conventional to transgenic apart.

Assuntos

RESUMO

Two field experiments were conducted in central Iowa to assess the effects of tillage on Heterodera glycines dissemination and reproduction and soybean (Glycine max) yield. Plots in both experiments were artificially infested with equivalent numbers of H. glycines cysts. In one experiment, plots were left noninfested or received aggregated or uniform infestation, and a susceptible soybean cultivar was grown for 3 years. By the end of the first growing season and through the second, H. glycines population densities were consistently greater (P ≤ 0.05) in uniformly infested plots than in plots with aggregated infestations. No differences in soybean yield among the treatments were detected. In a second experiment, a 1-m2 area of each plot was infested with H. glycines cysts, susceptible soybeans were grown for four seasons, and crop residue was managed with either ridge-, conventional-, reduced-, or no-tillage. After 1 year, nematode population densities were significantly (P ≤ 0.05) greater in conventional- and reduced-tillage treatments than in no- and ridge-tillage treatments. After 2 years, H. glycines had been disseminated 6.9 m from the infestation site in conventional- and reduced-tillage treatments but only 0.5 and 1.4 m for no-tillage and ridge-tillage treatments, respectively. After 3 years, H. glycines population densities were 10 times greater in conventional- and reduced-tillage treatments than in the no-tillage treatment; conventional-tillage was the only treatment with yield significantly lower (P ≤ 0.05) than the noninfested control. Aggregation of H. glycines eggs was greater (P ≤ 0.05) in no- and ridge-tillage treatments than in conventional- and reduced-tillage treatments. Results indicate tillage can quickly disseminate H. glycines in newly infested fields, facilitating more rapid nematode reproduction and subsequent yield loss.