Seasonal abundance of the serpentine leaf miner Liriomyza trifolii and the bio efficiency of the larval ectoparasitoid Diglyphus isaea on cowpea in Alejelat region, Libya

The American serpentine leaf miner, L. trifolii (Burgess), is one of the most problematic insect pest species attacking a large number of vegetable crops, weeds, and ornamentals. The present study aimed to determine the natural abundance of the larval parasitoid D. isaea and the serpentine leaf miner L. trifolii. This study was carried out in Alejelat region during two summer seasons of 2018 and 2019 on cowpea. The highest monthly total numbers of L. trifolii larvae, D. isaea, host fed, and total killed larvae that occurred on August recording (1187, 535, 209, and 744), respectively. While the monthly average numbers recorded (862.5 ± 289.8, 341.7 ± 139.5, 123.75 ± 57.3, and 465.5 ± 194.8) for the former parameters during season 2018, respectively. On the other hand, the highest monthly total numbers of L. trifolii larvae, D. isaea, host fed, and the total killed larvae occurred on August recording (3211, 1264, 580, and 1844), respectively. While the monthly average numbers recorded (1517.5 ± 1299.6, 632 ± 438.5, 285.5, ± 201.8, and 917.5 ± 640.2) for the former parameters during season 2019, respectively. The percentage of total mortality reached 91.8%, and 87.6 in the first and the second season, respectively

Compensatory uptake functions in empirical macroscopic root water uptake models: experimental and numerical analysis

[Departement_IRSTEA]Eaux [TR1_IRSTEA]GEUSIInternational audienceMacroscopic empirical root water uptake (RWU) models are often used in hydrological studies to predict water dynamics through the soil-plant-atmosphere continuum. RWU in macroscopic models is highly dependent on root density distribution (RDD). Therefore, compensatory uptake mechanisms are being increasingly considered to remedy this weakness. A common formulation of compensatory functions is to relate compensatory uptake rate to the plant water-stress status. This paper examines the efficiency of such compensatory functions to reduce the sensitivity of simulated actual transpiration (Ta), drainage (Draina) and RWU patterns to RDD. The possibility to replace the compensatory RWU functions by an adequate description of RDD is also discussed. The study was based on experimental and numerical analysis of two-dimensional soil-water dynamics of 11 maize plots, irrigated using sprinkler (Asp), subsurface drip (SDI) systems, or rainfed (RF). Soil-water dynamics were simulated using a physically-based soil-water flow model coupled to a macroscopic empirical compensatory RWU model. For each plot, simulation scenarios involved crossing 6 RDD profiles with 6 compensatory levels. RDD was found to be the main factor in the determination of RWU patterns, Ta and Draina rates, with and without the compensatory mechanism. The use of a water-tracking RDD, i.e., higher uptake intensity in expected wetter soil regions, was found a surrogate for compensatory RWU functions in surface-watering simulations (Asp and RF). However, in SDI simulations, a water-tracking RDD should be combined to a high level of compensatory uptake to satisfactorily reproduce real RWU patterns. Our results further suggest that the compensatory RWU process is independent of the plant stress status and should be seen as a response to heterogeneous soil-water distribution. Our results contribute to the identification of optimum parameterization of empirical RWU models as a function of watering methods

Optimizing Tomato Water and Fertilizer Uses in Smallholder Farms in South Africa Using the Piloten Model

The objectives of this paper are twofold: (i) to calibrate and validate the PILOTEN crop model for tomato (Solanumlycopersicum L.), and (ii) to use the model to examine the response of tomato yield to different irrigation and fertilization schedulingscenarios under varying climatic conditions in order to draw up management recommendations for smallholder farms. Thecalibration and validation were performed by using data collected from field experiments carried out in the north-east of SouthAfrica, on shallow Ferrosol and Luvisol soils. The scenarios dealt with: (i) the initial soil-water availability (fulfilling or not thesoil-water reserve at planting); (ii) the irrigation dose frequency (high versus low irrigation doses ranging from 10 to 40 mm perapplication); (iii) the fertilization dose frequency (full versus split fertilization application). The results indicated that only thefertilization scheduling may significantly affect tomato yields, while irrigation scheduling has a minor role. However, comparedto the local official irrigation guidelines, it is recommended to slightly increase the irrigation doses during the first 4 weeks ofgrowth for tomato grown between early September and mid-December, and to slightly decrease the doses in the second partof the growing cycles starting in February and May. It is also suggested to avoid applying the entire fertilizer dose after seedlingplanting for tomato grown between mid-February and late JuneCe travail a un double objectif: (i) calibrer et valider le modèle Piloten pour la tomate (Solanum lycopersicum L.) et (ii) utiliserle modèle pour analyser la réponse du rendement de la tomate à différents scénarios d’irrigation et de fertilisation, sousdifférentes conditions climatiques, afin de proposer des recommandations de conduites culturales aux petites exploitations.Le calage et la validation du modèle ont été effectués en utilisant des données recueillies par des expérimentations menées dansle nord-est de l’Afrique du Sud, sur des Ferrosols et des Luvisols peu profonds. Les scénarios ont traité: (i) de la disponibilitéinitiale en eau du sol (réserve en eau du sol reconstituée ou non à la plantation); (ii) du couple dose-fréquence d’irrigation(doses d’irrigation élevées à faibles allant de 10 à 40 mm par application); (iii) du couple dose-fréquence de fertilisation.Les résultats ont indiqué que seul le calendrier de la fertilisation peut affecter de manière significative les rendements de latomate, tandis que le calendrier d’irrigation joue un rôle mineur. En comparaison avec les recommandations locales de lagestion de l’irrigation et de la fertilisation de la tomate, il est recommandé d’augmenter légèrement les doses d’irrigation pendantles 4 premières semaines de croissance pour la tomate cultivée entre le début septembre et la mi-décembre, et de diminuerlégèrement les doses dans la deuxième partie du cycle de croissance commençant en février et en mai. Il est également suggéréd’éviter l’application de la totalité de la dose d’engrais après les semis de tomate cultivée entre mi-février et fin-jui

Analysis of sequence data to identify potential risk variants for oral clefts in multiplex families

Abstract Background: Nonsyndromic oral clefts are craniofacial malformations, which include cleft lip with or without cleft palate. The etiology for oral clefts is complex with both genetic and environmental factors contributing to risk. Previous genome‐wide association (GWAS) studies have identified multiple loci with small effects; however, many causal variants remain elusive. Methods: In this study, we address this by specifically looking for rare, potentially damaging variants in family‐based data. We analyzed both whole exome sequence (WES) data and whole genome sequence (WGS) data in multiplex cleft families to identify variants shared by affected individuals. Results: Here we present the results from these analyses. Our most interesting finding was from a single Syrian family, which showed enrichment of nonsynonymous and potentially damaging rare variants in two genes: CASP9 and FAT4. Conclusion: Neither of these candidate genes has previously been associated with oral clefts and, if confirmed as contributing to disease risk, may indicate novel biological pathways in the genetic etiology for oral clefts

Transdisciplinary innovation in irrigated smallholder agriculture in Africa

Boosting the productivity of smallholder farming systems continues to be a major need in Africa. Challenges relating to how to improve irrigation are multi-factor and multisectora l, and they involve a broad range of actors who must interact to reach decisions collectively. We provide a systematic reflection on findings from the research project EAU4Food, which adopted a transdisciplinary approach to irrigation for food security research in five case studies in Ethiopia, Mali, Mozambique, South Africa and Tunisia. The EAU4Food experiences emphasize that actual innovation at irrigated smallholder farm level remains limited without sufficient improvement of the enabling environment and taking note of the wider political economy environment. Most project partners felt at the end of the project that the transdisciplinary approach has indeed enriched the research process by providing different and multiple insights from actors outside the academic field. Local capacity to facilitate transdisciplinary research and engag ement with practitio ners was developed and could support the continuation and scaling up of the approach. Future projects may benefit from a longer time frame to allow for deeper exchange of lessons learned among different stakeholders and a dedicated effort to analyse possible improvements of the enabling environment from the beginning of the research process