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Can we use essential oils of Ocimum spp. to reduce aphids (Hemiptera: Aphididae) abundance on amaranth?
No full textTo address the growing concerns about the impact of synthetic pesticides on human and environmental health issues related to it, it is important to explore eco-friendly pest management strategies. This study evaluated the biocidal activity – mortality and fecundity – of Ocimum gratissimum and O. basilicum essential oils on Myzus persicae Sulzer and Aphis fabae Scopoli. Three concentrations used by ingestion (0.001, 0.01 and 0.1%) and by contact (0.01, 0.1 and 0.2%) for each essential oil were compared to the control (sucrose 15%). Both essential oils significantly induced aphid mortality and inhibited their fecundity compared to the control. However, higher concentrations – 0.1% by ingestion and 0.2% by contact – exhibited pronounced effects on aphid mortality. Regarding fecundity, aphid behaviour varied according to the essential oil and application method. A comprehensive chemical analysis using gas chromatography-flame ionization detection (GC-FID) coupled with gas chromatography-mass spectrometry (GC-MS) analysis indicated that the major compounds in O. gratissimum essential oil were thymol (28.3%), p-cymene (22.0%) and terpinene (10.6%), while O. basilicum essential oil contained estragol (75.2%), linalool (8.7%) and methyl eugenol (2.9%). In light of these findings, the potential use of Ocimum spp. essential oils as biopesticides for integrated pest management in vegetable crops and the harmful effects of synthetic pesticides on human health and the environment are discussed
The influence of farm resources and management decisions on the severity of Striga infestation and maize productivity in western Kenya
No full textThe control of Striga is of critical importance for smallholder farmers cultivating maize and other cereals in the western region of Kenya. Therefore, advanced knowledge and analysis is needed to understand farmers' resource endowment and decision making with regards to crop management, and the possible effect on Striga infestation and crop productivity. The overall objective of the study was to understand the role of resource endowment and allocation decisions on Striga infestation and maize productivity and offer effective and locally adapted options in western Kenya. The study used semi-structured questionnaires, focus group discussions and resource flow mapping to identify farm resources and key management decisions that are critical in management of Striga on smallholder farms. Soil was sampled from fields of selected farms and taken to the laboratory for analysis including Striga seed counts. In the fields, Striga shoots counts, and maize yield were recorded. Socio-economic variables such as land size, household income, labour availability, were used to construct a farm typology and assign farmers to different resource groups (RGs). Our results showed that household diversity leads to different land-use patterns, resource-use intensity and agricultural management practices which affect soil fertility and Striga infestation. Poor-resourced farmers tend to be associated with poor crop and soil management which results in maize fields with low soil fertility and high level of Striga infestation. Soil organic carbon showed a strong negative association with Striga infestation. Improving soil fertility is, therefore, the central component of any integrated and sustainable Striga management approaches, and technological solutions to address Striga and soil fertility issues, and they must be tailored to the farm and field diversity. The inclusion of legumes is highly recommended either as rotation or intercropping depending on land availability. Where possible, farmers may use mulch from previous crop residues to suppress weed emergence and prevent flowering and seed setting. Hand weeding though tiresome, remains a low-cost effective method to control Striga especially in areas where fields are small as in western Kenya
Sorghum genetic variability for adaptation to intercropping with cowpea in Sudano-Sahelian conditions
No full textContext: Intercropping is a crop diversification strategy that enhances the sustainability of agricultural production systems by delivering a range of ecosystem services. It minimizes the risk of crop failure and increases land-use efficiency. However, limited knowledge exists about the varieties and traits that can enhance the performance of cereal/legume intercropping systems. Objective: This study aims to explore the effect of sorghum genetic variability on intercropping performance and identify the genetic traits of sorghum that most influence the outcomes of intercropping. Method: Thirty sorghum varieties, representing a broad range of diversity, were grown both in pure stands and as intercrops, with a single cowpea variety used as a tester. The experiment was conducted in 2020 and 2021 in Burkina Faso, using a split-plot design with three replications each year. Genotype rankings were established for both cropping systems, and genotype × cropping system interactions were evaluated. Results: The total grain yield of the intercrop (sorghum + cowpea) was not significantly different from that of sorghum grown as a pure crop (2000 kg ha−1 and 2051 kg ha−1, respectively). However, the intercrop produced more grain protein (290 kg ha−1) than the pure crop (217 kg ha−1). Significant genotypic variability was observed for most traits, with few instances of significant genotype × cropping system interactions. No significant effect of sorghum genotypes on cowpea grain yield was found, nor was there a negative correlation between cowpea and sorghum grain yields in the intercrop. In 2021, competition was observed through a negative correlation between cowpea grain yield and sorghum biomass, as well as a positive correlation with sorghum harvest index. However, this competition was not for light, but for water. Conclusions: The choice of sorghum varieties for intercropping in our conditions depends mainly on the farmer's objectives regarding grain quality and production, avoiding varieties with high biomass and low harvest index. Further research should focus on the effect of cowpea genetic variability on the performance of sorghum-cowpea intercropping
Où en est le Cirad sur les données, codes et logiciels (production et partage) - Love Data Week 2025
No full textDans le cadre de la Love Data Week 2025, cette présentation qui introduit la journée propose un état des lieux de la production et du partage des données, codes et logiciels scientifiques au Cirad. À partir d'indicateurs issus du BSO (Baromètre Science Ouverte – en version bêta sur les données et les Codes) et des données internes du Cirad Dataverse https://dataverse.cirad.fr/ , plusieurs constats sont dressés sur les pratiques actuelles et les efforts à poursuivre pour une science plus ouverte et reproductible au Cirad. L'analyse repose sur des indicateurs en développement (version bêta) produits par le BSO, qui s'appuie sur le repérage automatique de mentions de production et de partage dans les publications scientifiques. Il est important de souligner que ces métriques ne doivent pas être utilisées telles quelles comme indicateurs externes, en raison des évolutions annuelles de la méthodologie. Le Cirad recommande de s'appuyer sur les expertises internes (notamment de la DiscO) pour interpréter ces données de manière rigoureuse : https://intranet-data.cirad.fr
New derbid planthoppers in the genus Muiravea (Hemiptera: Fulgoromorpha: Derbidae) from palms in eastern Madagascar, a key to the genus and an updated molecular phylogeny of available Malagasy Otiocerinae
No full textSurvey work in Madagascar documenting planthopper diversity on palms has resulted in the discovery of two new planthoppers in the genus Muiravea; M. maintysorokai sp. nov. and M. voanio sp. nov. Molecular data for the 18S rRNA gene, D9-D10 expansion region of the 28S rRNA gene and 5' region of the cytochrome c oxidase subunit I gene was generated and analyzed relative to available Derbidae from Madagascar and appropriate out-groups. A key is provided to the adult males of the genus Muiravea
Effect of climate on traits of dominant and rare tree species in the world's forests
Get PDFSpecies' traits and environmental conditions determine the abundance of tree species across the globe. The extent to which traits of dominant and rare tree species differ remains untested across a broad environmental range, limiting our understanding of how species traits and the environment shape forest functional composition. We use a global dataset of tree composition of >22,000 forest plots and 11 traits of 1663 tree species to ask how locally dominant and rare species differ in their trait values, and how these differences are driven by climatic gradients in temperature and water availability in forest biomes across the globe. We find three consistent trait differences between locally dominant and rare species across all biomes; dominant species are taller, have softer wood and higher loading on the multivariate stem strategy axis (related to narrow tracheids and thick bark). The difference between traits of dominant and rare species is more strongly driven by temperature compared to water availability, as temperature might affect a larger number of traits. Therefore, climate change driven global temperature rise may have a strong effect on trait differences between dominant and rare tree species and may lead to changes in species abundances and therefore strong community reassembly
Évaluation de la résistance aux fongicides des populations de Mycosphaerella fijiensis, agent de la Cercosporiose Noire des bananiers, en Martinique - Campagne 2024
No full textRapport caravane de l'agroécologie - 2025. Étape lac de Guiers - 14 et 15 mai 2025 - Richard Toll. Département de Dagana, région Saint Louis
No full textLa Caisse alimentaire commune de Montpellier. Une recherche-action de démocratie alimentaire. 2022-2024. Rapport final
Get PDFThe use of fire to preserve biodiversity under novel fire regimes
Get PDFNovel fire regimes are emerging worldwide and pose substantial challenges to biodiversity conservation. Addressing these challenges and mitigating their impacts on biodiversity will require developing a wide range of fire management practices. In this paper, we leverage research across taxa, ecosystems and continents to highlight strategies for applying fire knowledge in biodiversity conservation. First, we define novel fire regimes and outline different fire management practices in contemporary landscapes from different parts of the world. Next, we synthesize recent research on fire use and biodiversity, and provide a decision-making framework for biodiversity conservation under novel fire regimes. We recommend that fire management strategies for preserving biodiversity should consider both social and ecological factors, iterative learning informed by effective monitoring, and developing and testing new management actions. An integrated approach to learning about fire and biodiversity will help to navigate the complexities of novel fire regimes and preserve biodiversity in a rapidly changing world