References of "El Jarroudi, Moussa"
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See detailCinétique de décroissance de la surface verte et estimation du rendement du blé d’hiver
Kouadio, Amani Louis ULg; Djaby, Bakary ULg; Grégory, Duveiller et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(2), 179-191

A large number of agrometeorological models for crop yield assessment are available with various levels of complexity and empiricism. However, the current development of models for wheat yield forecasting ... [more ▼]

A large number of agrometeorological models for crop yield assessment are available with various levels of complexity and empiricism. However, the current development of models for wheat yield forecasting does not always reflect the inclusion of the loss of valuable green area and its relation to biotic and abiotic processes in production situation. In this study the senescence phase of winter wheat (Triticum aestivum L.) is monitored through the GAI (Green Area Index), calculated from digital hemispherical photography taken over plots in Belgium, Grand-Duchy of Luxembourg and France. Two curve-fitting functions (modified Gompertz and modified logistic) are used to describe the senescence phase. Metrics derived from these functions and characterizing this phase (i.e. the maximum value of GAI, the senescence rate and the time taken to reach either 37% or 50% of the green surface in the senescent phase) are related to final grain yields. The regression-based models calculated with these metrics showed that final yield could be estimated with a coefficient of determination of 0,83 and a RMSE of 0,48 t.ha-1. Such simple models may be considered as a first yield estimates that may be performed in order to provide a better integrated yield assessment in operational systems. Indeed, estimation of cereal-crop production, particularly wheat, is considered as a priority in most crop research programs due to the relevance of food grain to world agricultural production. [less ▲]

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See detailMaladies du blé d'hiver au Luxembourg Les interactions entre climat, sol et phytotechnie montrent l'importance primordiale du facteur climat
El Jarroudi, Moussa ULg; Giraud, Frédéric; Delfosse, Philippe et al

in Phytoma : La Défense des Végétaux (2012), 650

Malgré sa petite taille, le GDL est caractérisé par deux régions très contrastées en ce qui concerne les maladies cryptogamiques du blé d’hiver. Une analyse en composante principale a permis d’analyser la ... [more ▼]

Malgré sa petite taille, le GDL est caractérisé par deux régions très contrastées en ce qui concerne les maladies cryptogamiques du blé d’hiver. Une analyse en composante principale a permis d’analyser la distribution des maladies cryptogamiques entre le Gutland et l’Oseling. La distribution des maladies cryptogamiques est significativement différente (P < 0.001) entre le Gutland et l’Oesling. Entre 2003 et 2009, la septoriose et la rouille brune sont des maladies qui caractérisent le Gutland avec respectivement comme pourcentage 51 et 17%. Dans l’Oesling, la sévérité de ces maladies était très faible et n’atteignait même pas 1%. A l’opposé, l’Oesling est caractérisée par l’installation de l’Oïdium surtout en 2003 et 2009 avec respectivement 15 et 40% de sévérité alors cette maladie ne dépassait pas 1% de sévérité en Gutland. Parallèlement à ces maladies, d’autres pathogènes fongiques sont observées uniquement en Gutland et les maladies qu’ils causent sont influencées par la phytotechnie. Il s’agit de l’helminthosporiose et de la rouille jaune avec comme caractéristique le contournement du gène de résistance Yr 17+. La variation dans l’expression des maladies cryptogamiques entre le Gutland et l’Oesling est surtout due aux différences marquées des conditions climatiques entre les deux régions mais aussi aux pratiques agricoles en vigueur (fumure azotée, choix variétal, semis avec labour ou sans labour….). [less ▲]

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See detailEstimating regional wheat yield from the shape of decreasing curves of green area index temporal profiles retrieved from MODIS data
Kouadio, Amani Louis ULg; Duveiller, Gregory; Djaby, Bakary ULg et al

in International Journal of Applied Earth Observation and Geoinformation (2012), 18

Earth observation data, owing to their synoptic, timely and repetitive coverage, have been recognized as a valuable tool for crop monitoring at different levels. At the field level, the close correlation ... [more ▼]

Earth observation data, owing to their synoptic, timely and repetitive coverage, have been recognized as a valuable tool for crop monitoring at different levels. At the field level, the close correlation between green leaf area (GLA) during maturation and grain yield in wheat revealed that the onset and rate of senescence appeared to be important factors for determining wheat grain yield. Our study sought to explore a simple approach for wheat yield forecasting at the regional level, based on metrics derived from the senescence phase of the green area index (GAI) retrieved from remote sensing data. This study took advantage of recent methodological improvements in which imagery with high revisit frequency but coarse spatial resolution can be exploited to derive crop-specific GAI time series by selecting pixels whose ground-projected instantaneous field of view is dominated by the target crop: winter wheat. A logistic function was used to characterize the GAI senescence phase and derive the metrics of this phase. Four regression-based models involving these metrics (i.e., the maximum GAI value, the senescence date and the thermal time taken to reach 50% of the green surface in the senescent phase) were related to official wheat yield data. The performances of such models at this regional scale showed that final yield could be estimated with an RMSE of 0.57 ton ha−1, representing about 7% as relative RMSE. Such an approach may be considered as a first yield estimate that could be performed in order to provide better integrated yield assessments in operational systems. [less ▲]

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See detailImages hémisphériques et leur analyse pour prévoir le rendement du blé d’hiver. Comment la phase de décroissance de la surface verte de la plante nous renseigne-t-elle sur le rendement final ?
Kouadio, Amani Louis ULg; Djaby, Bakary ULg; Giraud, Frédéric et al

in Phytoma : La Défense des Végétaux (2011), 648

The prediction of cereal-crop yield is considered as a priority in most crop research programmes due to the relevance of food grain to feeding the world population. Today, a large number of ... [more ▼]

The prediction of cereal-crop yield is considered as a priority in most crop research programmes due to the relevance of food grain to feeding the world population. Today, a large number of agrometeorological models for crop yield assessment are available with various levels of complexity and empiricism. But, currently the development of wheat yield forecasting models in conventional operational systems do not reflect the loss of active green leaf area and its relation to biotic and abiotic processes implicated in the crop production situation. In 2009 a large field campaign in the Grand-Duchy of Luxembourg was realized to assess the validity of leaf-green-area approach to further improve yield prediction. Hemispherical photography were taken on winter wheat fields during the crop cycle, preferentially from inflorescence emergence to maturity. The variable of interest, the Green Area Index (GAI), was retrieved after image analyses using the CAN-EYE software. The regression-based models calculated with metrics derived from the decreasing curves of GAI showed that final yield could be better estimated with satisfactory precision: range of the coefficient of determination (R²) varies from 0.73 to 0.86 and RMSE (root mean square error) is varying between 0.43 and 0.56 t/ha. The validation of such approach at the scale of an agricultural zone or region is currently under progress, by using green area index temporal profiles and information on the phenology of winter wheat. Such simple models may be considered as a first step towards yield estimation that may be completed by other agrometeorological models in order to provide a better integrated yield assessment. [less ▲]

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See detailRegional-based typology of the main fungal diseases affecting winter wheat.
El Jarroudi, Moussa ULg; Giraud, Frédéric; Delfosse, Philippe et al

Poster (2011, August 06)

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See detailNew method for establishing a network of operational warning of Septoria leaf blotch disease in winter wheat
El Jarroudi, Moussa ULg; Giraud, Frédéric; Defosse, Philippe et al

Poster (2011, August 06)

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See detailNew method for establishing a network of operational warning of Septoria leaf blotch disease in winter wheat
El Jarroudi, Moussa ULg; Giraud, Frédéric; Delfosse, Philippe et al

in Phytopathology (2011), 101

A mechanistic model, PROCULTURE, based on commonly available meteorological data and assessing in real time the risk of progression of septoria leaf blotch disease on winter wheat has been developed in ... [more ▼]

A mechanistic model, PROCULTURE, based on commonly available meteorological data and assessing in real time the risk of progression of septoria leaf blotch disease on winter wheat has been developed in Belgium and the Grand-Duchy of Luxemburg (GDL) to limit fungicide use. However, the reliability of meteorological stations used for the warning system varies according to the distance to the fields. A weather analysis based on the Fourier transform highlighted a great difference in the intraday variation between two sites in the GDL (Everlange and Reuland). The correlation between these two sites is very high for the hourly temperature (R = 0.96), and for the hourly relative humidity (RH) (R = 0.86), (P < 0.05). However, the intraday variation (<11 hours) highlights contrasts for a given meteorological parameter. Hence, the correlation between temperature or RH decreased respectively from 0.96 to 0.43 and from 0.86 to 0.30. The comparison between infection conditions given by PROCULTURE using the Fourier transform, shows: (i) a positive but weak correlation between temperature at Reuland and Everlange (R = 0.64), (ii) a good correlation between RH for these two sites (R = 0.86), and (iii) a contrasted difference for rain (R = 0.27), (P < 0.05). This Fourier transform based method enables to take into account the RH and temperature variation related to topography levels in the warning system and to understand and explain the variation in disease expression between a plateau and a valley bottom or between North and South slopes. [less ▲]

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See detailPerformance of leaf wetness sensor used in winter wheat disease management
Mahtour, Abdeslam ULg; El Jarroudi, Moussa ULg; Hoffmann, Lucien et al

Poster (2011, May 26)

Wetness on crop leaves has particular epidemiological significance because many fungal diseases affect plants only when free moisture is present on leaves. The leaf wetness sensor detects the presence of ... [more ▼]

Wetness on crop leaves has particular epidemiological significance because many fungal diseases affect plants only when free moisture is present on leaves. The leaf wetness sensor detects the presence of wetness on a leaf’s surface, enabling researchers and producers to forecast disease and protect plant canopies, and consequently to optimize fungicide application and often reduce environmental load. This research project aimed at better understanding the leaf wetness duration and its influence in winter wheat disease. Measurement of surface wetness duration by three electronic flat-plate sensors (Model 237-Campbell Scientific, Inc) in wheat fields were compared with tactile and visual observations in replicated field experiments at the site of Arlon (Belgium) during the period May-July 2006 and April-July 2007. Performances of the sensor were evaluated against SWEB model outputs and visual observations of disease symptoms. On the field, dew-onset and dry-off of wetness on leaves were observed visually (with a flash light for dew-onset) at 15-minute intervals. Each sensor was placed close the flag leaf. For the three sensors, the two dew-onset and dry-off times measured in both 2006 and 2007 crop seasons gave a leaf wetness duration (LWD) which was on average one hour less than visual observations. In order to establish a relationship between the surface wetness periods and wheat foliar diseases, LWD was compared with the Septoria leaf blotch (SLB) development risk (main winter wheat disease). A minimal surface wetness duration favourable to infection for SLB was established. [less ▲]

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See detailPrévoir la septoriose : un modèle belge au Luxembourg
El Jarroudi, Moussa ULg; Giraud, Frédéric; Tychon, Bernard ULg et al

in Phytoma : La Défense des Végétaux (2011), 642

Septoria leaf blight caused by Septoria tritici Roberge ex Desmaz. (anamorph of Mycosphaerella graminicola) is one of the most serious foliar diseases on winter wheat which farmers in Luxembourg. It need ... [more ▼]

Septoria leaf blight caused by Septoria tritici Roberge ex Desmaz. (anamorph of Mycosphaerella graminicola) is one of the most serious foliar diseases on winter wheat which farmers in Luxembourg. It need to take into account when deciding upon fungicide application during stem elongation. Management of S. tritici aims at keeping the top two leaf layers free from infection, as these leaves contribute most to grain yield. The model PROCULTURE has been developed to simulate the progress of the Septoria leaf blotch disease on winter wheat during the cropping season. The model has been validated in Luxembourg for 3-years (2000 to 2002) at distinct representative sites. Proculture forecasts have been shown to be correct in about 85% of all cases. This model has since 2004 been used in the Grand-Duchy of Luxemburg in order to find the optimum time of fungicide spray in fields. On average, no spray of fungicides or only one application is required to efficiently control Septoria leaf blotch. In the Oesling (north of G-D of Luxembourg), treatments based on the Septoria risk simulation model were recommended only once, in 2007. The climatic conditions of the Oesling tend to favour organic farming in a region where foliar disease pressure is very weak. [less ▲]

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See detailSite-specific Septoria Leaf Blotch Risk Assessment in Winter Wheat using Weather-Radar Rainfall Estimates
Mahtour, Abdeslam ULg; El Jarroudi, Moussa ULg; Delobbe, Laurent et al

in Plant Disease (2011), 10.1094/PDIS-07-10-0482

The Septoria leaf blotch prediction model PROCULTURE was used to assess the impact on simulated infection rates when using rainfall estimated by radar instead of rain gauge measurements. When comparing ... [more ▼]

The Septoria leaf blotch prediction model PROCULTURE was used to assess the impact on simulated infection rates when using rainfall estimated by radar instead of rain gauge measurements. When comparing infection events simulated by PROCULTURE using radar- and gauge-derived data, the probability of detection (PODs) of infection events was high (0.83 on average), and the false alarm ratio (FARs) of infection events was not negligible (0.24 on average). For most stations, FARso of infection events decreased to 0 and PODso increased (0.85 on average) when the model outputs for both datasets were compared against visual observations of disease symptoms. An analysis of 148 infection events over three years at four locations showed no significant difference in the number of infection events of simulations using either dataset, indicating that, for a given location, radar estimates were as reliable as rain gauges for predicting infection events. Radar also provided better estimates of rainfall occurrence over a continuous space than weather station networks. The high spatial resolution provides radar with an important advantage that could significantly improve existing warning systems. [less ▲]

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See detailTIMELY FUNGICIDE APPLICATION: A STRATEGY TO MINIMIZE FUSARIUM HEAD BLIGHT AND ASSOCIATED MYCOTOXIN PRODUCTION IN WINTER WHEAT
Giraud, Frédéric; Pasquali, Mattias; El Jarroudi, Moussa ULg et al

in Journal of Plant Pathology [=JPP] (2011), 93(1, supplement), 115-118

Re-emergence of Fusarium head blight (FHB) on wheat should be taken into account in the global management of cropped fields, especially with respect to fungicide application schemes, due to harmful toxin ... [more ▼]

Re-emergence of Fusarium head blight (FHB) on wheat should be taken into account in the global management of cropped fields, especially with respect to fungicide application schemes, due to harmful toxin production. The aim of this study was to assess, in three experimental fields representative of the various topoclimatological zones of Luxembourg, the impact of timing of fungicide spray application on the prevalence and severity of FHB, the concentration of mycotoxins, and Fusarium strain pattern in winter wheat. It was found that fungicide treatments and the time of application had a significant impact on the amount of deoxynivalenol (DON) detected (P=0.027, ANOVA). In our experimental design, the application of fungicides at 3 different times increased the amount of DON in winter wheat compared to two and single applications. The importance of the timing of fungicide application is discussed in relation to limiting toxin contamination in the field. [less ▲]

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See detailRegional-based typology of the main fungal diseases affecting winter wheat in the Grand-Duchy of Luxembourg
El Jarroudi, Moussa ULg; Giraud, Frédéric; Delfosse, Philippe et al

in Phytopathology (2011), 101

Despite its small territory size, the Grand-Duchy of Luxembourg (GDL) has several microclimates that result in a variability of disease severity between the South (Gutland) and the North (Oesling ... [more ▼]

Despite its small territory size, the Grand-Duchy of Luxembourg (GDL) has several microclimates that result in a variability of disease severity between the South (Gutland) and the North (Oesling). Septoria leaf blotch disease of wheat is an important disease in the GDL. Over 2003–2009, the severity was strong in Gutland (51% on average over the last two upper leaves at the late milk growth stage) and low in the Oesling (16% for the same leaves). For the years 2006, 2008 and 2009, the disease severity was less than 6% in the Oesling while it exceeded 40% in the Gutland. The second fungal disease that has become economically important is the wheat leaf rust. Over the same period, the Gutland and the Oesling showed consistently the highest and lowest disease severity respectively. In 2003 and 2007, the Gutland showed the highest disease severity with 66% and 57% respectively, whereas the lowest severity (<1%) was observed in the Oesling. Another important disease is wheat powdery mildew. The 2003 and 2009 cropping seasons showed the highest disease severity with 15% and 40%, respectively, in the Oesling whereas less than 1% severity was registered in the Gutland. Fusarium head blight was also present in the eastern part of the Gutland showing the highest prevalence and severity in 2007 and 2008 (8.5% and 8.3% respectively). These prevalence and severity percentages were significantly higher compared to the Oesling (% prevalence % severity, p = 0.049 and p = 0.012, respectively, Tukey’s test). [less ▲]

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See detailSITE – SPECIFIC MONITORING FOR DISEASE FORECASTING IN WINTER WHEAT.
El Jarroudi, Moussa ULg; Giraud, Frédéric; Delfosse, Philippe et al

in Journal of Plant Pathology [=JPP] (2011), 93(Supplement 1), 19-20

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See detailFirst report of the breakdown of the YR17 resistance gene to wheat stripe rust in the Grand Duchy of Luxembourg
El Jarroudi, Moussa ULg; Giraud, Frédéric; Tychon, Bernard ULg et al

in Journal of Plant Pathology [=JPP] (2011), 93(1), 243

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See detailAzoxystrobin and epoximazole sensitivity profiles of Mycosphaerella graminicola populations from the Grand-Duchy of Luxemburg in 2007 and 2008
Vrancken, Carine; Dubos, Tiphaine; El Jarroudi, Moussa ULg et al

Poster (2010, December 07)

Mycosphaerella graminicola strains were isolated from symptomatic winter wheat (Triticum aestivum) and spelt (Triticum spelta) leaves sampled across the Grand-Duchy of Luxembourg. In total, 484 strains ... [more ▼]

Mycosphaerella graminicola strains were isolated from symptomatic winter wheat (Triticum aestivum) and spelt (Triticum spelta) leaves sampled across the Grand-Duchy of Luxembourg. In total, 484 strains were isolated from winter wheat, and 31 from spelt leaves. The sensitivity profiles of these strains towards azoxystrobin (Amistar®, Syngenta Agro GmbH, Germany) and against epoxiconazole (Opus®, BASF Belgium NV/S A, Brussels, Belgium) were assessed in microplates, allowing to test 10 different concentrations for each active substance (0, 0.00316, 0.01, 0.0316, 0.1, 0.316, 1, 3.16, 10 and 31.6μg/mL). 100μ g/mL of salicylhydroxamic acid (SHAM) was also added to the medium, in order to prevent the strains from using alternative respiration. Results of the sensitivity tests for azoxystrobin showed a dose-dependent decrease of in vitro growth for all the strains. During both years, strains could be divided into two distinct sub-populations in relation to their azoxystrobin sensitivity, thus forming a bimodal distribution commonly reported to be associated with a single gene-mediated resistance. For wheat, the dominant sub-population was the one showing full resistance to azoxystrobin. The results of the sensitivity tests to epoxiconazole in liquid media showed a dose-dependent decrease of fungal growth for all the strains tested. The EC50 values followed an unimodal distribution. When the sensitivity distribution of the strains collected in 2008 (n=379) was compared to that observed in 2007, although the populations have remained unimodal, a minor shift towards less sensitive populations was observed. Compared to strains originating from wheat, the spelt strains were more sensitive towards both fungicides (p ≤ 0.001). [less ▲]

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See detailSensitivity of simulated surface wetness duration to meteorological variations in three different regions of Grand-Duchy of Luxembourg
Mahtour, Abdeslam ULg; El Jarroudi, Moussa ULg; Hoffmann, Lucien et al

Poster (2010, November 23)

Surface wetness duration (SWD) is an important factor influencing the occurrence of winter wheat diseases. For this reason, SWD is extremely important for the management of crop protection activities. In ... [more ▼]

Surface wetness duration (SWD) is an important factor influencing the occurrence of winter wheat diseases. For this reason, SWD is extremely important for the management of crop protection activities. In order to understand the SWD variability and its influence on winter wheat disease, the objective of this study was to (i) determine the sensitivity of our model on varying input plant parameters and (ii) to evaluate the influence of simulated SWD to meteorological variations in three different climatic regions of the Grand-Duchy of Luxembourg (EVERLANGE, OBERCORN and SCHIMPACH). In this work, an agrometeorological model known as the Surface Wetness Energy Balance (SWEB) was applied for the simulation of SWD. The model was previously applied in another study for winter wheat cultivars and was adapted for use with agrometeorological data easily available from standard meteorological monitoring stations. Based on weather data and simulated SWD data, sensitivity analyses were performed to compare the effects of relative humidity, air temperature, wind speed and net radiation on wetness duration over one growing season (March-July) at three test sites. The results indicated that the sensitivities were very similar at three sites and there was no spatial trend (i.e. difference between locations) in the sensitivities. However, the model is most sensitive to relative humidity and differences between 0.5 and 25 h (per month) SWD were found when increasing/decreasing relative humidity by 10%. The model was least sensitive to changes in air temperature, showing differences of only 0.5–2 h (per month) in SWD. Intermediate sensitivity is found for rainfall, net radiation and wind speed. Among the input plant parameters values, SWD was most sensitive to the maximum fraction of canopy allowed as wet surface area, leaf area index, maximum water storage per unit area and least sensitive to crop height. The sensitivity to parameter values was less important compared to the sensitivity to the meteorological variable relative humidity. [less ▲]

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See detailSensitivity of simulated surface wetness duration to meteorological variations in three different regions of the Grand-Duchy of Luxembourg
Mahtour, Abdeslam; El Jarroudi, Moussa ULg; Hoffmann, Lucien et al

Poster (2010, November 22)

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See detailSite–specific monitoring for disease forecasting in winter wheat.
El Jarroudi, Moussa ULg; Giraud, Frédéric; Delfosse, Philippe et al

Conference (2010, November 22)

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