Influência de fontes e doses de fungicidas cúpricos e estrobilurinas aplicadas em consonância com eventos chuvosos no controle da mancha preta dos citros
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2017-11-13
Autores
Franco, Danilo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Neste estudo, foram realizados três experimentos (E1, E2 e E3). Os dois primeiros experimentos (E1 e E2) referem-se a avaliações da eficiência dose-resposta dos fungicidas hidróxido de cobre (HC), oxicloreto de cobre (OC) e óxido cuproso (OCp), aplicados nos estádios F1 e F2, no controle de Phyllosticta citricarpa, agente causal da mancha preta dos citros (MPC). E, no terceiro experimento (E3), foi avaliada a influência da aplicação de piraclostrobina em consonância com eventos chuvosos, no controle da MPC. Em E1 e E2 os fungicidas e dosagens avaliadas foram (g de cobre metálico 100 L-1 de calda): HC (43,7; 35,0; e 26,2; OC (100,8; 90,7; e 68,0) e; OCp (90,0; 56,3; e 42,2). No experimento E1 foram utilizadas plantas de laranjeira ‘Pera’, sob condições naturais de infecção, em Olímpia/SP. Foi adotado o delineamento experimental de blocos ao acaso, com quatro repetições. Cada parcela foi constituída de 33 plantas. Os fungicidas foram aplicados mediante turbopulverizador e vazão de 135 mL de calda m-3 de copa. Posteriormente, em todos os tratamentos, a partir do estádio F4 foram realizadas quatro aplicações de azoxistrobina a 75 g de i.a. 2.000 L-1, em intervalo de 42 dias. Foram realizadas quatro avaliações mensais, de agosto a novembro, amostrando-se casualmente 100 frutos nas seis plantas centrais da parcela, determinando-se a incidência (I) e severidade dos sintomas mediante escala de notas. A partir dos dados de severidade dos sintomas foi determinado o índice de doença (ID). Com os dados de ID, ao longo do tempo, calculou-se a área abaixo da curva de progresso da doença (AACPD). Em E2 foram empregadas plantas de laranjeira ‘Pera‘, também em Olímpia/SP. Os tratamentos avaliados foram semelhantes aos anteriormente citados, sendo, porém, aplicados com pulverizador manual do tipo “De Vilbs”, com volume suficiente para cobertura uniforme dos frutos. Foi adotado o delineamento de blocos ao acaso, em arranjo fatorial 10 tratamentos, sendo nove combinações de fungicidas cúpricos e uma testemunha, sem fungicida) x 5 (épocas de inoculação) e 4 (repetições). Cada parcela foi constituída por 20 frutos previamente ensacados com papel semi-kraft, no estádio F1. Posteriormente, no estádio F4, procedeu-se remoção dos sacos de papel, seguido do tratamento dos frutos exclusivamente com fungicidas cúpricos. O tratamento dos frutos deu-se mediante sua imersão, durante x segundos, na calda fungicida acrescida de óleo mineral a x%. Posteriormente, após secagem da calda procedeu-se o reensacamento dos frutos. A seguir, em intervalo semanal, entre 0 a 28 dias após o tratamento, foi realizada inoculação mediante aspersão de suspensão contendo 104 conídios mL-1. Na avaliação, realizada quando da colheita da maturação dos frutos, foram determinados os valores de I e ID. O experimento E3 foi realizado em pomar comercial de laranjeira ‘Folha Murcha’, no município de Paraíso/SP. Inicialmente, nos estádios F1 e F2 foram realizadas duas aplicações de oxicloreto de cobre (90 g de cobre metálico 100 L-1 de calda). Os tratamentos avaliados foram: aplicação do fungicida piraclostrobina em intervalo de 14 dias entre si, na dose de 25 g 2000 L-1; aplicação de piraclostrobina, na dose de 75 g 2000L-1 após o primeiro evento de chuva ocorrido 14 dias após a última aplicação do tratamento; aplicação de piraclostrobina, na dose de 75 g 2000L-1 após o primeiro evento de chuva, ocorrido 35 dias após a última aplicação do tratamento; aplicação de piraclostrobina, com intervalo de 42 dias entre si nas doses de 50 e 75 g 2000L-1. Esses tratamentos foram comparados com o tratamento padrão de azoxistrobina, na dose de 75 g 2000L-1, aplicado em intervalo de 42 dias. Foi utilizado o delineamento de blocos casualizados, e cada parcela foi constituída por 66 plantas. As condições operacionais adotadas para aplicação dos fungicidas foram semelhantes às adotadas em E1, porém com 150 mL de calda m-3 de copa. Os critérios de avaliações foram semelhantes aos citados em E1, em intervalos mensais, de setembro a janeiro. Concluiu-se que os fungicidas HC, OC e OCp nas doses de 43,7, 90,7 e 56,3 g de cobre metálico 100 L-1, respectivamente, aplicados nos estádios F1 e F2, complementado por aplicações de azoxistrobina, foram igualmente eficientes no controle de MPC. A eficiência do efeito protetor dos fungicidas cúpricos foi constatada por pelo menos 28 dias após a sua aplicação. Porém, a maior eficiência dos fungicidas cúpricos deu-se quando da sua aplicação previamente à inoculação de P. citricarpa. Aplicações de piraclostrobina a 75 g de i.a. 2000L-1 em intervalo de no mínimo 14 dias entre eventos chuvosos resultaram em maior controle da doença, quando comparado aos demais intervalos e doses de piraclostrobina e a azoxistrobina, na dose de 75 g 2.000 L-1, em intervalo fixo de 42 dias, com consequente redução da incidência e severidade de sintomas de MPC.
In this study, three experiments were performed (E1, E2 and E3). The first two experiments refer to the rate-response efficiency of the fungicides copper hydroxide (HC), copper oxychloride (OC) and cuprous oxide (OCp) in the control of Phyllosticta citricarpa, causal agent of citrus black spot (CBS). And the third (E3) the influence of pyraclostrobin application was evaluated in consonance with rainy events. In E1 and E2 the evaluated rates were: HC (43.7; 35.0; and 26.2 g of metallic copper 100L-1); OC (100.8, 90.7, and 68.0 g of metallic copper 100L-1); OCp (90.0, 56.3, and 42.2 g of metallic copper 100L-1). The experiment (E1) was conducted under natural infection by P. citricarpa in 'Pera' sweet orange planted in Olímpia/SP. A randomized blocks design was used, with four replications. Each plot was represented by 33 plants. The fungicides were applied in stages F1 and F2 by turbosprayer and 135 ml m-3 of the tree canopy. Subsequently, in F4 stage, all treatments were treated with azoxystrobin at 75 g 2000 L-1, four times in a 42-day interval. Four monthly evaluations were performed, from August to November, evaluating 100 fruits to determining the incidence and symptoms severity. Data were used to determined area under disease progress curve (AUDPC). In E2, a 'Pera' sweet orange plants were used, also located in Olímpia/SP. The treatments evaluated were similar those previously in E1, but were applied by a manual "De Vilbs" sprayer, with sufficient volum for uniform fruit coverage. A randomized blocks design were used in a factorial arrangement of 10 treatments (9 copper fungicides treatments and one untreated check) x 5 (inoculation times) and 4 (replicates). Each plot was formed by 20 pre-bagged fruits with semi-kraft paper in the F1 stage. In the F4 stage the bags were removed and the fruits sprayed exclusively with copper fungicides. Subsequently, in a weekly interval from 0 to 28 days after application at inoculation with suspension spray containing 104 conidia mL-1 was performed. In the harvest time an evaluation was performed and the values of I and DI were determined. E3 was carried out in a commercial 'Folha Murcha' sweet orange orchard, in Paraíso/SP. Initially, in stages F1 and F2, two applications of copper oxychloride based on 90 g of metallic copper 100 L-1 were perfomed. The treatments evaluated were: application with 14 days fixed interval in the pyraclostrobin rate of 25 g 2000L-1; application of 75 g 2000L-1 after the first rain event occurred 14 days after the last fungicide application; application of 75 g 2000L-1 after the first rain event occurred 35 days after the last fungicide application; application with 42 days fixed interval of 50 and 75 g 2000L-1. These treatments were compared with the standard treatment with 42 days fixed interval of azoxystrobin at rate 75 g 2000L-1. A randomized blocks design was used with 66 plants per plot. The fungicides applications were similar that in E1, but with 150 mL m-3 of canopy volume. The evaluations were similar that in E1, in monthly intervals, from September to January, in the ten central plants per plots. It was concluded that the fungicides HC, OC and OCp in the rates of 43.7, 90.7 and 56.3 g of metallic copper 100 L-1, respectively, applied in stages F1 and F2, complemented by applications of azoxystrobin, were equally efficient to control CBS. The protective effect of the copper fungicides was maintained until 28 days after treatment. However, the best response was obtained when inoculating P. citricarpa immediately after copper fungicides treatment. The 75 g 2000L-1 of pyraclostrobin application after the first rainy event occurred at least 14 days from the last fungicide application resulted in a greater reduction in the incidence and severity of CBS symptoms.
In this study, three experiments were performed (E1, E2 and E3). The first two experiments refer to the rate-response efficiency of the fungicides copper hydroxide (HC), copper oxychloride (OC) and cuprous oxide (OCp) in the control of Phyllosticta citricarpa, causal agent of citrus black spot (CBS). And the third (E3) the influence of pyraclostrobin application was evaluated in consonance with rainy events. In E1 and E2 the evaluated rates were: HC (43.7; 35.0; and 26.2 g of metallic copper 100L-1); OC (100.8, 90.7, and 68.0 g of metallic copper 100L-1); OCp (90.0, 56.3, and 42.2 g of metallic copper 100L-1). The experiment (E1) was conducted under natural infection by P. citricarpa in 'Pera' sweet orange planted in Olímpia/SP. A randomized blocks design was used, with four replications. Each plot was represented by 33 plants. The fungicides were applied in stages F1 and F2 by turbosprayer and 135 ml m-3 of the tree canopy. Subsequently, in F4 stage, all treatments were treated with azoxystrobin at 75 g 2000 L-1, four times in a 42-day interval. Four monthly evaluations were performed, from August to November, evaluating 100 fruits to determining the incidence and symptoms severity. Data were used to determined area under disease progress curve (AUDPC). In E2, a 'Pera' sweet orange plants were used, also located in Olímpia/SP. The treatments evaluated were similar those previously in E1, but were applied by a manual "De Vilbs" sprayer, with sufficient volum for uniform fruit coverage. A randomized blocks design were used in a factorial arrangement of 10 treatments (9 copper fungicides treatments and one untreated check) x 5 (inoculation times) and 4 (replicates). Each plot was formed by 20 pre-bagged fruits with semi-kraft paper in the F1 stage. In the F4 stage the bags were removed and the fruits sprayed exclusively with copper fungicides. Subsequently, in a weekly interval from 0 to 28 days after application at inoculation with suspension spray containing 104 conidia mL-1 was performed. In the harvest time an evaluation was performed and the values of I and DI were determined. E3 was carried out in a commercial 'Folha Murcha' sweet orange orchard, in Paraíso/SP. Initially, in stages F1 and F2, two applications of copper oxychloride based on 90 g of metallic copper 100 L-1 were perfomed. The treatments evaluated were: application with 14 days fixed interval in the pyraclostrobin rate of 25 g 2000L-1; application of 75 g 2000L-1 after the first rain event occurred 14 days after the last fungicide application; application of 75 g 2000L-1 after the first rain event occurred 35 days after the last fungicide application; application with 42 days fixed interval of 50 and 75 g 2000L-1. These treatments were compared with the standard treatment with 42 days fixed interval of azoxystrobin at rate 75 g 2000L-1. A randomized blocks design was used with 66 plants per plot. The fungicides applications were similar that in E1, but with 150 mL m-3 of canopy volume. The evaluations were similar that in E1, in monthly intervals, from September to January, in the ten central plants per plots. It was concluded that the fungicides HC, OC and OCp in the rates of 43.7, 90.7 and 56.3 g of metallic copper 100 L-1, respectively, applied in stages F1 and F2, complemented by applications of azoxystrobin, were equally efficient to control CBS. The protective effect of the copper fungicides was maintained until 28 days after treatment. However, the best response was obtained when inoculating P. citricarpa immediately after copper fungicides treatment. The 75 g 2000L-1 of pyraclostrobin application after the first rainy event occurred at least 14 days from the last fungicide application resulted in a greater reduction in the incidence and severity of CBS symptoms.
Descrição
Palavras-chave
Citrus sinensis, Phyllosticta citricarpa, piraclostrobina, hidróxido de cobre, oxicloreto de cobre, óxido cuproso, pyraclostrobin, copper hydroxide, copper oxychloride, cuprous oxide