Postinfection Activity of Selected Late Blight Fungicides

Johnson, Dennis A.; Cummings, Thomas F.; Geary, Brad

doi:10.1094/pdis.2000.84.10.1116

Cited by 23 publications

(18 citation statements)

References 14 publications

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“…It is possible that application timing and intervals between applications for mancozeb may not have been sufficient to optimize its effectiveness in this experiment. Therefore, contact or protectant fungicides need to be used preventatively instead of post-infection for effective control of late blight (Johnson et al 2000;Mayton et al 2001). …”

Section: Discussionmentioning

confidence: 99%

Efficacy of fungicide mixtures for the management of Phytophthora infestans (US-1) on potato

Muchiri

Narla

Olanya

et al. 2010

phyto

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Fungicide application strategies (timing, frequency, rates and mixtures) are important for the control and resistance management of potato late blight caused by Phytophthora infestans. The efficacy of fungicide mixtures consisting of fenamidone + mancozeb and propamocarb HCL + mancozeb at various rates and in spray regimes containing metalaxyl and mancozeb was evaluated for late blight control (US-1) at four locations in Kenya. Propamocarb HCL + mancozeb significantly (P < 0.05) reduced foliar blight compared with mancozeb and the untreated control under moderate to severe disease pressure. Disease severity was significantly lower following application of propamocarb HCL + mancozeb at a rate of 4L ha-1 than at rates of 2L and 3L ha-1 in 1999 and 2000, but it was not significantly lower following applications at a rate of 3L ha-1 in 2000 and 2001. There were no significant differences in mean final late blight score among the three rates of 0.9, 1.0 and 1.1 kg ha-1 of fenamidone + mancozeb. All fungicide mixtures and application sequences significantly reduced the area under the disease progress curve and final late blight scores as compared with the unprotected control. Total and marketable tuber yield significantly (P < 0.05) increased in all fungicide-treated plots.

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Section: Discussionmentioning

confidence: 99%

Efficacy of fungicide mixtures for the management of Phytophthora infestans (US-1) on potato

Muchiri

Narla

Olanya

et al. 2010

phyto

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“…The combination of propamocarb+fluopicolide present high residual, protective, curative and anti-sporulating effect due to the chemical characteristics of the molecules (JOHNSON et al, 2000;SOUZA et al, 2014). Fluopicolide has transblade action, tending to create a protective layer under the leaf surface, acting on the pathogen by interrupting important metabolic pathways for protein synthesis of oomycetes (TAFFOREAU et al, 2006;LATORSE et al, 2007).…”

Section: Resultsmentioning

confidence: 99%

“…Fluopicolide has transblade action, tending to create a protective layer under the leaf surface, acting on the pathogen by interrupting important metabolic pathways for protein synthesis of oomycetes (TAFFOREAU et al, 2006;LATORSE et al, 2007). Propamocarb, in turn, penetrates the plant tissue, moving and acting directly on the development of fungal vegetative and reproductive structures (JOHNSON et al, 2000).…”

Section: Resultsmentioning

confidence: 99%

Chemical control of phytophthora wilt in tomatoes

Mendonça¹,

Coelho²,

Stracieri³

et al. 2015

Biosci. J.

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ABSTRACT:The most effective disease management method for yield reducing diseases affecting tomatoes is the use of fungicides. This study evaluated the efficacy of chemical control on three Phytophthora sp. isolates, pathogenic to tomatoes. The effect of fungicides on mycelial growth of Phytophthora sp. and on tomato wilt was evaluated in vitro and in vivo. Two tests were done in Petri plates, and one on seedlings, in completely randomized design as a 4x3 factorial, with 5 replications. In vitro tests were done in growth chamber, at 25°C. The experimental unit consisted of a 5-mm diameter fungal mycelial plug placed 30 mm away from a filter paper disk, of similar size, soaked in fungicide, over cornmeal agar. The first test evaluated four commercial products registered for the control of potato blight: chlorothalonil+metalaxyl (Folio Gold ® 742.5 WP); propamocarb chloridrate (Infinito ® 687.5 CS), metalaxyl-m+mancozeb (Ridomil Gold ® 68 WP), cymoxanil + manconzeb (Curzate ® MZ 72 WG), at the recommended doses. The other assays evaluated three doses of Infinito (0.125%, 0.150% or 0.175%) and Ridomil. In vivo test was done in the greenhouse, and the experimental unit consisted of one pot, containing one tomato seedling, cultivar Alambra F1. Fungicide was drenched on the seedling soil one day prior to inoculation with 50,000 zoospores per pot. Data of mycelia growth inhibition by fungicide were submitted to analysis of variance and the averages compared by the Tukey test at 5% significance; efficacy was determined as a function of Ridomil®, the standard fungicide. In the first test, regardless of isolate, Infinito® presented performance similar to Ridomil ® with efficacy of 98.5%, while Folio Gold ® presented efficacy of 57.3% and Curzate ® had no fungicide effect. Growth of isolate PP3 was smaller in all fungicides. In the second in vitro test, all three doses of Infinito ® had efficacy above 82%. The best control was observed on isolates PP3 and PP4. In the third test, in vivo, no significant differences were observed in root matter among the standard fungicide and the doses of Infinito ® ; however, efficacy of Infinito ® at 0.175% was 14% greater than that obtained with Ridomil ® . It can be concluded that Infinito ® is one more option for the control of tomato wilt.

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“…According to these authors, the two mixtures, under critical periods of rain, were more effective in the control of late blight when compared to cyazofamid, dimethomorph + mancozeb, and zoxamide + mancozeb. The rainfastness of fluopicolide + propamocarb and fenamidone + propamocarb can be explained by the significant translaminar effect of fluopicolide, and systemic effect of propamocarb (JOHNSON; CUMMINGS; GEARY, 2000;TAFFOREAU et al, 2006).…”

Section: Resultsmentioning

confidence: 99%

Effect of simulated rain on the efficiency of fungicides in potato late blight and early blight control

Töfoli

Domingues

Melo³

et al. 2014

Sem. Ci. Agr.

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Rainfastness of fungicides used in the control of late blight (Phytophthora infestans) and early blight (Alternaria solani) of potato was evaluated under green house and laboratory conditions. 'Agata' and 'Monalisa' plants treated with fungicides against both diseases were subjected to 20 mm controlled rain simulation for 6 min at 30 min, 1, 2, and 4 h after application. Once all leaves had dried, foliar discs were transferred to Petri dishes and inoculated with the respective pathogens. The plates were then incubated in a BOD chamber for a 12-h photoperiod at 18°C and 25°C, respectively. Disease severity was evaluated by determining the area (%) of the foliar discs affected by disease on 5 and 7 days postinoculation. The results suggest that systemic or inherent tenacity fungicides were less influenced by the simulated rain as compared to contact fungicides. An increase in drying time promoted higher control levels of both diseases, indicating a better retention and absorption of the tested fungicides. Key words: Phytophthora infestans, Alternaria solani, Solanum tuberosum L., tenacity, rainfastness ResumoA resistência de fungicidas à chuva no controle da requeima (Phytophthora infestans) e pinta preta (Alternaria solani) da batata foi avaliada em condições de casa-se vegetação e laboratório. Plantas de batata das cultivares Agata e Monalisa tratadas com fungicidas indicados para as duas doenças foram submetidas à chuva controlada de 20 mm durante 6 minutos aos 30 minutos, 1, 2 e 4 horas após a pulverização. Após a secagem das plantas, discos foliares foram coletados e transferidos para placas de Petri e inoculados com os patógenos. Em seguida as placas foram incubadas em câmara BOD a 18° C para P. infestans e 25 ° C para A. solani, sob fotoperíodo de 12 horas. A severidade foi avaliada através da porcentagem da área do disco afetada pelas doenças aos 5 e 7 dias após a inoculação, respectivamente. Os resultados obtidos permitiram concluir que os fungicidas sistêmicos, translaminares ou com tenacidade inerente foram menos afetados pela chuva simulada quando comparados aos fungicidas de contato. O aumento do tempo de secagem promoveu maiores níveis de controle da requeima e pinta preta, evidenciando uma maior retenção ou absorção dos produtos testados.

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Postinfection Activity of Selected Late Blight Fungicides

Cited by 23 publications

References 14 publications

Efficacy of fungicide mixtures for the management of Phytophthora infestans (US-1) on potato

Efficacy of fungicide mixtures for the management of Phytophthora infestans (US-1) on potato

Chemical control of phytophthora wilt in tomatoes

Effect of simulated rain on the efficiency of fungicides in potato late blight and early blight control

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