scholarly journals Rainfall Thresholds as Support for Timing Fungicide Applications in the Control of Potato Late Blight in Ecuador and Peru

Plant Disease ◽  
2009 ◽  
Vol 93 (2) ◽  
pp. 142-148 ◽  
Author(s):  
Peter Kromann ◽  
Arturo Taipe ◽  
Willmer G. Perez ◽  
Gregory A. Forbes

Accumulated rainfall thresholds were studied in seven field experiments conducted in Ecuador and Peru for their value in timing applications of fungicide to control potato late blight, caused by Phytophthora infestans. Fungicide regimes based on accumulated rainfall thresholds ranging from 10 to 70 mm were compared with calendar spray schemes of every 5 or 7 days. Very low thresholds of 10 to 20 mm gave similar levels of control and resulted in similar number of sprays as did calendar spraying. However, neither low thresholds nor calendar sprays were effective in protecting susceptible potato genotypes in over half of the experiments. Thresholds of 25 to 50 mm of rainfall led to reduction in the number of sprays needed to protect resistant cultivars but also resulted in high levels of disease on susceptible cultivars. We conclude that timing fungicide sprays based on accumulated rainfall thresholds could be a successful component of integrated management strategies that include cultivars with moderate or high levels of resistance. The simplicity of measuring accumulated rainfall means that the technology can potentially be used by resource-poor farmers in developing countries.

Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 1008-1015 ◽  
Author(s):  
Peter Kromann ◽  
Willmer G. Pérez ◽  
Arturo Taipe ◽  
Elmar Schulte-Geldermann ◽  
Buddhi Prakash Sharma ◽  
...  

Twenty phosphonate products found in the agrochemical market in Ecuador and Peru were evaluated in bioassays for the control of foliar potato late blight, caused by Phytophthora infestans. Eight phosphonate products were evaluated in 16 field experiments done in Peru, Ecuador, Kenya, and Nepal. A meta-analysis across locations involving 71 combinations of potato genotype by site and year demonstrated a significant relationship between phosphonate application rate and efficacy for controlling late blight on potato foliage. The meta-analysis revealed that phosphonate rates of approximately 2.5 g a.i./liter provided efficacy similar to that of the conventional contact fungicides mancozeb and chlorothalonil used at similar rates. At rates higher than 2.5 g a.i./liter, the efficacy of phosphonate was superior to the contact fungicides. Overall, late blight control by phosphonate appeared relatively stable in field experiments across locations. An analysis of field experiments and 64 combinations of potato genotype by site and year showed no correlation between the susceptibility level of potato genotypes and efficacy of phosphonates. The cost of both phosphonate compounds and contact fungicides varied greatly among the countries of the field study; however, in Kenya, control with phosphonate was clearly less expensive than with mancozeb.


2018 ◽  
Vol 34 (6) ◽  
pp. 4-11
Author(s):  
V.K. Chizhik ◽  
◽  
E.A. Sokolova ◽  
V.V. Martynov ◽  
M.A. Kuznetsova ◽  
...  

Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 935-942 ◽  
Author(s):  
Toky Rakotonindraina ◽  
Jean-Éric Chauvin ◽  
Roland Pellé ◽  
Robert Faivre ◽  
Catherine Chatot ◽  
...  

The Shtienberg model for predicting yield loss caused by Phytophthora infestans in potato was developed and parameterized in the 1990s in North America. The predictive quality of this model was evaluated in France for a wide range of epidemics under different soil and weather conditions and on cultivars different than those used to estimate its parameters. A field experiment was carried out in 2006, 2007, 2008, and 2009 in Brittany, western France to assess late blight severity and yield losses. The dynamics of late blight were monitored on eight cultivars with varying types and levels of resistance. The model correctly predicted relative yield losses (efficiency = 0.80, root mean square error of prediction = 13.25%, and bias = –0.36%) as a function of weather and the observed disease dynamics for a wide range of late blight epidemics. In addition to the evaluation of the predictive quality of the model, this article provides a dataset that describes the development of various late blight epidemics on potato as a function of weather conditions, fungicide regimes, and cultivar susceptibility. Following this evaluation, the Shtienberg model can be used with confidence in research and development programs to better manage potato late blight in France.


2017 ◽  
Vol 2 (1) ◽  
pp. 90-91
Author(s):  
Virupaksh U. Patil ◽  
G. Vanishree ◽  
Debasis Pattanayak ◽  
Sanjeev Sharma ◽  
Vinay Bhardwaj ◽  
...  

2017 ◽  
Vol 12 (4) ◽  
pp. e1300733 ◽  
Author(s):  
Soriya Rin ◽  
Yuri Mizuno ◽  
Yusuke Shibata ◽  
Mayuka Fushimi ◽  
Shinpei Katou ◽  
...  

2010 ◽  
Vol 11 (1) ◽  
pp. 21
Author(s):  
Hugo F. Rivera ◽  
Erika P. Martínez ◽  
Jairo A. Osorio ◽  
Edgar Martínez

<p>Phytophthora infestans (Mont.) de Bary, agente causal de la gota de la papa, es considerado la principal limitante de la producción de este cultivo en Colombia. El control habitual del patógeno se realiza con fungicidas de tipo sistémico, que incrementan los costos de producción, pueden inducir la resistencia del patógeno y tiene un impacto negativo en el ambiente. Por tanto, se llevó a cabo este estudio con el propósito de buscar alternativas amigables con el ambiente, que hagan parte de un paquete tecnológico eficaz de control. Dos cepas nativas de Psedomonas fluorescens (039T y 021V), provenientes de cultivos de papa, fueron evaluadas contra P. infestans. Las suspensiones bacterianas y los biosurfactantes parcialmente purificados (BPP), producidos por éstas (obtenidos en medio mínimo de sales con querosén), fueron aplicados sobre foliolos desprendidos en ensayos in vitro y experimentos in vivo en plantas de papa, en condiciones controladas en casa de malla. Los resultados demostraron la capacidad que tienen los biosurfactantes y las suspensiones bacterianas para controlar al patógeno, ya que el BPP 039T logró reducir el nivel de severidad de la enfermedad en 79,9% in vitro y 38,5% in vivo, mientras que el BPP 021V redujo en 78,7% in vitro y 30,2% in vivo. Las suspensiones bacterianas redujeron el nivel de severidad en 72,4% (039T) y 66,1% (021V) en las evaluaciones in vitro y 35% en los experimentos in vivo. Los resultados de esta investigación muestran el potencial que tienen los biosurfactantes para el control de la gota en Colombia.</p><p> </p><p><strong>Evaluation of Biosurfactants Produced by Pseudomonas fluorescens for Potato Late Blight Control (Phytophthora infestans (Mont) de Bary) Under Controlled Conditions</strong></p><p>Phytophthora infestans (Mont.) de Bary, causal agent of potato late blight is considered the main limiting pathogen for the production of this crop in Colombia. The usual control of the disease has been performed with systemic fungicides which increase production costs, can induce pathogen resistance and have a negative impact on the environment. Therefore, this study was carried out in order to find effective and environmentally friendly control alternatives for potato late blight. Two Pseudomonas fluorescens native strains (039T and 021V) isolated from potato crops were evaluated against P. infestans. Bacterial suspensions (obtained from minimal salts medium added with kerosene) and partially purified biosurfactants (BPP) were applied on detached leaflets for in vitro assays and on potato plants in greenhouse, for in vivo assays and the measure of inhibitory effect of the disease was assessed. The results showed the ability of P. fluorescens biosurfactants and bacterial suspensions to control the pathogen. BPP 039T was able to reduce the level of severity disease by 79.9% in vitro and 38.5% in vivo, whereas BPP 021V decreased 78.7% in vitro and 30.2% in vivo. Bacterial suspensions reduced the severity level in 72.4% (039T) and 66.1% (021V) in vitro assessments and 35% in the in vivo experiment. These results show the potential of P. fluorescens biosurfactants to control the potato late blight in Colombia.</p>


2020 ◽  
Vol 46 (3) ◽  
pp. 191-197
Author(s):  
Nilceu Ricetti Xavier de Nazareno ◽  
Maria Renate Finckh ◽  
Lutécia Beatriz dos Santos Canalli ◽  
Inês Fumiko Ubukata Yada ◽  
Jackson Kawakami

ABSTRACT Field experiments were conducted during spring 2014 and fall and spring 2015 to determine the effect of fresh mulch on the development of Phytophthora infestans epidemics, in Lapa Municipality, Parana State, southern Brazil. The used cultivars were ‘Agata’, susceptible, and ‘BRS Ana’, moderately susceptible. The main treatment consisted in manually applying a 10cm-thick layer of fresh mulch when potato sprouts were emerging. Fresh mulch was prepared with plants available at that time of the year. For the spring experiments, fresh mulch was a mixture of oats, rye grass and wild radish (60 t/ha) and for the fall experiment, semi-ripe elephant grass (90 t/ha). Plots consisted of six 10m-long rows, spaced at 0.8m, containing 28 plants per row. Experimental design was in completely randomized blocks with four replicates. Natural inoculum was adopted. Percentage of leaf area was weekly estimated until the end of the plant cycle and the area under the disease progress curve (AUDPC) was calculated. Application of fresh mulch significantly reduced AUDPC by 32.1%, 12.4% and 23.1%, compared to control in all seasons, for ‘BRS Ana’ and by 26.1%, 2.8% and 12.0% for ‘Agata’. Application of fresh mulch showed to be a promising practice for the integrated management of late blight and for the protection of yields, especially in periods more favorable to the development of the disease. More detailed studies should be conducted on the plant type and amount of fresh mulch to be used, as well as on the possibility of reducing concentrations or increasing intervals between fungicide sprays.


2010 ◽  
Vol 25 (2) ◽  
pp. 157-161
Author(s):  
Emil Rekanovic ◽  
Milos Stepanovic ◽  
Milan Stevic ◽  
Ivana Potocnik ◽  
Biljana Todorovic ◽  
...  

The efficacy of mandipropamid (Revus 250 SC) in controlling Phytophthora infestans in potato was evaluated in field trials. The efficacies of Revus 250 SC in comparison with standard fungicides Quadris (azoxystrobin) were tested in several localities in Serbia (Kasarske Livade, Valjevska Kamenica and Opovo) in 2007 and 2008. Both of the tested fungicides exhibited high efficacy in controlling potato late blight. The differencies in the efficacy of Revus 250 SC (96.3- 99.2%) and Quadris (94.1-95.5%) were insignificant. Our experiments showed that the investigated fungicide was highly effective against P. infestans even under high disease pressure.


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