Influence of environmental factors on field concentrations ofAlternaria solani conidia above a South African potato crop

Waals, J. E. van der; Korsten, Lisé; Aveling, T.A.S.; Denner, F. D. N.

doi:10.1007/bf02979806

Cited by 36 publications

(34 citation statements)

References 23 publications

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“…These minimum humidity requirements occurred in the 2007 and 2009 cycles before of the appearance of the spores in the air, as shown in the column of IWP days of the Table 3 for the first peaks proposed. Van der Waals et al (2003) applied the IWP model to a South African potato crop. The weather in this geographic area is very different from ours, with very high temperatures recorded during the growing season and large temperature differences between day and night, which affect the humidity.…”

Section: Discussionmentioning

confidence: 99%

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Effects of meteorological factors on the levels of Alternaria spores on a potato crop

et al. 2010

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Alternaria solani Soraeur produces early blight in Solanum tuberosum L., leading to significant agricultural losses. The current study was carried out on the extensive potato crop situated in north-western of Spain during 2007, 2008 and 2009. In this area potato crops are the most important source of income. In this work we used a Hirst-type volumetric spore-trap for the aerobiological monitoring of Alternaria spores. The highest spore concentrations were recorded during the 2009 cycle (10,555 spores), and the lowest concentrations were recorded during the 2008 cycle (5,471 spores). Over the 3 years of study, the highest concentrations were registered during the last stage of the crop. The aim of the study was to observe the influence of meteorological factors on the concentration of Alternaria spores, which can lead to serious infection and early blight. Prediction of the stages during which a crop is particularly vulnerable to infection allows for adjustment of the application of fungicide and is of environmental and agricultural importance. For this reason, we tested three models (P-Days, DD and IWP) to predict the first treatment and decrease the negative effect that these spores have on potato crops. The parameter that showed the most significant correlation with spore concentrations was minimum temperature. We used ARIMA (autoregressive integrated model of running mean) time-series models to determine the forecast. We considered weather data as predictor variables and the concentration of spores on the previous day as the fixed variable.

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Section: Discussionmentioning

confidence: 99%

“…An IWP day occurs when this parameter is higher than 95% for 6 consecutive hours at night, and there are 6 h or less with a relative humidity less than 80% (Van der Waals et al 2003).…”

Section: Methodsmentioning

confidence: 99%

Effects of meteorological factors on the levels of Alternaria spores on a potato crop

et al. 2010

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“…An IWP day is when this parameter is higher than 95% for six consecutive hours at night, and there are six or fewer hours with a relative humidity inferior to 80% during the day and during six consecutive days (Van der Waals, Corsten, Avelino, & Denner, 2003).…”

Section: Methodsmentioning

confidence: 99%

Evaluation of the different Alternaria prediction models on a potato crop in A Limia (NW of Spain)

2007

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The main crop of the A Limia region is the potato, with an average production of 5 million kilos per year, under the protected geographic indication (IGP) Pataca de Galicia (Galician potato) label recognized by the European Community. Alternaria represents an important part of the pathogenic fungus spectra on this crop, representing an average of 1.9-3.1% of the spores collected. It represents the fourth and third most common type, respectively, in the years of study, after the Cladosporium type (which represented 80% and 64% respectively in each year of study), the Basidia type (5.5% and 1.4%), Botrytis (3.5% and 1.3%), and Fusarium (2.7% and 25.2%). A Lanzoni VPPS 2000 Hirst volumetric sampler was placed in Damil, in the region of A Limia in order to determine the airborne concentration of Alternaria conidium over a potato crop and finally to try to establish the most suitable prediction models for Alternaria attacks and how they might be controlled. We applied different models based on temperature, such as the model of propitious days (P-Days), the model of accumulation of disfavourable days (DD), and the relative humidity model of interrupted wet periods (IWP). The most efficient model was found to be the interrupted wet periods (IWP) method as it could predict several days of attack during the development of the crop. It is efficient in A Limia even when the features described in this model are fulfilled during five consecutive days. In the first year of study the efficiency of this method was lower as alternariosis did not proliferate to the same degree due to the adverse meteorological conditions registered for the development of the fungus. This study is the first step towards prediction of infection by Alternaria inpotato crops. We need more years of study in order to adjust these models to the conditions of the sampling area, and thus be able to confirm the necessary values and their suitability with the aim of developing possible alternatives to reduce the negative consequences of this pathogen.

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“…However, according to Bashi and Rotem (1974), who did extensive studies on these pathogens, under favourable relative humidity or leaf wetness, the minimum, optimum and maximum temperatures required for infection are 10°C, 25°C and 35°C, respectively. Van der Waals et al (2003) have shown that the development of early blight in South Africa also occurs at these temperatures. What is important to note is that interrupted wetting periods (IWP) are more important than high leaf wetness for spore germination and dispersal of A. solani (Bashi and Rotem 1974;van der Waals et al 2003).…”

Section: Introductionmentioning

confidence: 99%

“…Van der Waals et al (2003) have shown that the development of early blight in South Africa also occurs at these temperatures. What is important to note is that interrupted wetting periods (IWP) are more important than high leaf wetness for spore germination and dispersal of A. solani (Bashi and Rotem 1974;van der Waals et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Climate Change and Potato Production in Contrasting South African Agro-Ecosystems 3. Effects on Relative Development Rates of Selected Pathogens and Pests

et al. 2013

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A set of daily weather data simulations for 1961 to 2050 were used to calculate past and future trends in pest and disease pressure in potato cropping systems at three agro-ecologically distinct sites in South Africa: the Sandveld, the Eastern Free State and Limpopo. The diseases and pests modelled were late blight, early blight and brown spot, blackleg and soft rot, root-knot nematodes and the peach-potato aphid Myzus persicae (as indicator of Potato virus Y and Potato leaf roll virus). The effects of climate on trends in relative development rates of these pathogens and pests were modelled for each pathogen and pest using a set of quantitative parameters, which included specific temperature and moisture requirements for population growth, compiled from literature. Results showed that the cumulative relative development rate (cRDR) of soft rot and blackleg, root-knot nematodes and M. persicae will increase over the 90-year period in the areas under consideration. The cRDR of early blight and brown spot is likely to increase in the wet winter and wet summer crops of the Sandveld and Eastern Free State, respectively, but remains unchanged in the dry summer and dry winter crops of the Sandveld and Limpopo, respectively. Climate change will decrease the cRDR of late blight in all of the cropping systems modelled, except in the wet winter crop of the Sandveld. These results help to set priorities in research and breeding, specifically in relation to management strategies for diseases and pests.Potato Research (2013) 56:67-84 DOI 10.1007/s11540-013-9231-

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Influence of environmental factors on field concentrations ofAlternaria solani conidia above a South African potato crop

Cited by 36 publications

References 23 publications

Effects of meteorological factors on the levels of Alternaria spores on a potato crop

Effects of meteorological factors on the levels of Alternaria spores on a potato crop

Evaluation of the different Alternaria prediction models on a potato crop in A Limia (NW of Spain)

Climate Change and Potato Production in Contrasting South African Agro-Ecosystems 3. Effects on Relative Development Rates of Selected Pathogens and Pests

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