Management of Root Knot Nematode Affecting Banana Crop by Using Organic Amendment And Biological Products

Plant-parasitic nematodes are a major obstacle to sustainable banana production in Morocco. With rarefaction of efficient nematicide, safe and alternative methods need to be developed. This research aims at evaluating the efficiency of some bioproducts: Biocompost (B), Ricinus communis Powder (RP), combined Biocompost with R. communis Powder (RP + B) and a bionematicide based on Paecilomyces lilacinus commercialised as Nemacont (N) against Meloidogyne javanica. All the mentioned treatments not only reduced root knot nematode density and roots gall index significantly, but also improved plant growth. The R. communis powder is the most efficient biological product on M. javanica population suppression and on banana plant growth enhancing. Keywords: Ricinus communis, Nemacont, Paecilomyces lilacinus, Biocompost, Meloidogyne javanica, banana

Antifungal activity of medicinal plants extracts against Botrytis cinerea the causal agent of gray mold on tomato

Four aromatic and medicinal plants of the Souss-Massa region were tested for their efficiency in reducing postharvest gray mold of tomato fruits caused by Botrytis cinerea in vitro and in vivo experiment. This antifungal activity was tested using two types of extracts: organic plant extract and aqueous extracts. When they are used at 1000 ppm, the four organic plant extracts of Asteriscus imbricatus inhibit completely the growth of B. cinerea. However complete inhibition of the mycelia growth of the pathogen was observed at 2000ppm concentration by ether and chloroform extracts of Pulicaria mauritanica. Moreover, the organic extracts of Lavandula dentata showed a moderate antifungal effect; while the four organic extracts of Globularia alpym have no effect on the studied fungus. The aqueous extract of Asteriscus imbricatus has inhibited completely the growth of B. cinerea at 20000 ppm. The aqueous extract of P. mauritanica showed a moderate antifungal effect, while the aqueous extracts L. dentata and the aqueous extracts of G. alpym were ineffective against B. cinerea. The in vivo test shows that disease incidence decrease as the concentration of A. imbricatus and P. mauritanica extracts increase. This study has demonstrated that organics and aqueous extracts of these two plants are promising antifungal agents which could be used as bio-fungicide in tomato crops protection against B. cinerea. Keywords: Antifungal activity, extracts, Medicinal plants, Botrytis cinerea, postharvest

Quantitative and Qualitative Analysis by HPLC of Major Peganum harmala Alkaloids at Different Stages of Development

The analysis of major Peganum harmala alkaloids (harmaline, harmine, harmol and harmalol) has shown that the content of these secondary metabolites depends on the plant development stage. The qualitative and quantitative profile of major alkaloids change significantly between stems, leaves and roots. The roots and seeds are the richest and most diversified organs in these metabolites. The concentration of the major alkaloids in all organs increases during the first three weeks and stabilizes at a constant level during vegetative growth phase and then decline at the beginning of flowering. On the scale of the whole plant, major alkaloids concentration of P. harmala varies with the developmental stage of the plant between 21.16 and 26.96 mg/g and harmine remains the most abundant molecule. Optimum exploitation of these natural products from the P. harmala plant is possible if the harvest of plant material occurs during the vegetative growth phase and at the appropriate stage for the richest organ. Keywords: Peganum harmala, Plant growth, Alkaloids, Harmine, Harmaline, Harmol, Harmalo

Anti-nematode Effect Assessment of Peganum harmala Based-Products Against Meloidogyne javanica on Melon

Natural products from plant origin have been tested for their potential to develop viable components of plant parasitic nematode management strategies especially against Meloidogyne javanica. Different products based on P. harmala seed evaluated in pot experiments against M. javanica associated to Cucumis melo L. crop showed that when they are used as soil amendment in pre-planting, not only reduces densities of M. javanica in soil and crop damage to melon crops, but also improves significantly growth parameters except for the emulsified oil of P. harmala which proved a phytotoxic effect although it gave a complete suppression of M. javanica. The aqueous extract and the seeds powder are among the less phytotoxic substances, which are efficient against these pathogens. P. harmala-seed-based-products have a potential antinematodes effect against Meloidogyne javanica and can be used as component of an integrated management system to control this root knot nematode. Keywords: nematodes management, Peganum harmala; extracts, organic amendment, Cucumis mel

Plant-parasitic nematodes parasitizing saffron in Morocco: Structuring drivers and biological risk identification

International audiencePlant-parasitic nematodes (PPN) are the most destructive of all plant pathogens. They are an economically important group of soil pathogens, causing significant annual damages of up to 25% of world crop production. Morocco is considered to be a highly productive country for the colorant/medicinal/spice saffron (Crocus sativus L.). Taliouine and Taznakht regions are the most productive areas of this valuable neutraceutical. Due to its metabolic profile, and growth forms, saffron is susceptible to many plant diseases, including plant-parasitic nematodes (PPN). This work aims to assess the diversity of PPN communities in soils of Taliouine and Taznakht regions to facilitate understanding of links between their assemblages with biotic and abiotic parameters. Herein, nematode communities were characterized in 163 soil samples collected from 11 rural communes characterized by altitudinal gradients in Taliouine and Taznakht regions. Fifteen PPN genera belonging to 12 families were identified, among which the four genera Ditylenchus, Aphelenchoides, Pratylenchus and Helicotylenchus, potentiate serious limiting factors in saffron production. Their frequencies are respectively 92, 49, 48 and 36% in the area of Taliouine, while in Taznakht they represent 95, 69, 33, and 28% respectively. Regarding the assessment of diversity at different sites, the genus richness (R) index ranges from 2 to 10 distinct genera, whereas the Shannon diversity (H’) index varies from 0.9 to 1.5 and the Evenness (E) index tends to 1. The Co-inertia analyses revealed a substantial relationship between nematode communities and soil types. Soil texture is the major factor influencing the presence and the abundance of a considerable portion of genera. Multivariate analyses (MBPLS) indicated links between humidity, rainfall, minimum temperature and PPN taxa, though maximum temperature did not have an impact. Ditylenchus, Helicotylenchus, Pratylenchus and Paratylenchus were related to the humidity and silt soil that developed in Taliouine. Aphelenchoides, Tylenchus, Tylenchorynchus and Dorylaimus were more prevalent in rainy locations and clay soils of Taznakht. Suitable nematode controlling approaches may be applied and preventative measures should be considered at nursery and field level

La dispersion passive de champignons prédateurs par les substrats de culture peut-elle favoriser le biocontrôle des nématodes phytoparasites en pépinières d’oliviers ?

International audienceDescription of the subject: In Morocco, expanding agricultural sector under "Morocco Green Plan" will also introduce plant diseases and plant parasitic nematodes (PPN). Soil substrate used in most of the olive nurseries is potentially inhabited by PPN and natural enemies.Objectives: This work assessed the co-occurrence of PPN and nematophagous fungi (NF) in substrates and potential of NF to suppress PPN. Method: The diversity of PPN and NF genera was characterized in 305 substrate samples, isolated from 25 olive nurseries and functional activity (nematicidal and enzymatic) of NF was evaluated.Results: High PPN diversity was detected in the isolated samples and substrates were differentiated by NF activity. Global partition between PPN and NF diversity patterns confirmed prey-predator antagonism. Moreover, PPN-NF patterns depend on the fungal survival (saprophytes vs obligate parasites) and antagonism (predation vs toxicity) processes. However, even the NF strains with maximum fitness (growth, sporulation, enzymatic activity) were not inevitably the most effective against PPN. Consequently, it was hypothesized that predation and competition could be an adaptation process of NF to overcome environmental stress and exploit alternative or supplementary nutrient sources.Conclusions: The use of diverse native NF from cultivated and wild soils offer future prospects for the development of PPN management strategies in olive nurseries.Description du sujet : Au Maroc, le développement d’une agriculture intensive dans le cadre du « Plan Maroc Vert » induira très probablement l’émergence de pathologies végétales, dont des nématoses. Dans le cas de l’olivier, la majorité des pépiniéristes utilisent des substrats constitués de sols d'origine indigène potentiellement contaminés en nématodes phytoparasites (NPP) et en champignons nématophages (CNP). Objectifs : Le but de ce travail était de pouvoir évaluer la co-occurrence des NPP et des CNP dans les substrats ainsi que le potentiel antagoniste des CNP. Méthode : La diversité des genres de NPP et de CNP a été caractérisée dans 305 échantillons de substrats prélevés dans 25 pépinières d'oliviers. L'activité fonctionnelle (nématicide et enzymatique) des CNP a été évaluée.Résultats : Une grande diversité de NPP a été détectée, dont les 10 espèces les plus pathogènes à l’échelle mondiale. Les substrats se sont avérés riches en CNP qui diffèrent par leur activité prédatrice. L’analyse des communautés a révélé une partition nette entre NPP et CNP dans les substrats, confirmant l’antagonisme proie-prédateur. De plus, les patrons de NPP et de CNP dépendent de la stratégie trophique des CNP (saprophytes vs parasites obligatoires) et du mode d’antagonisme (prédation vs toxicité) impliqués. Mais les souches de CNP les plus performantes (croissance, sporulation, activité enzymatique) n'étaient pas forcément les plus efficaces contre les NPP. Par conséquent, la prédation et la compétition pourraient être un processus d'adaptation permettant au CNP de surmonter le stress environnemental et d'exploiter des sources nutritives alternatives ou supplémentaires.Conclusions : L'utilisation des CNP indigènes offre des perspectives pour le développement de stratégies de gestion microbiologique des NPP respectueuses de l’environnement

Diversity of nematophagous fungi in Moroccan olive nurseries: Highlighting prey-predator interactions and efficient strains against root-knot nematodes

International audiencePlant-parasitic nematodes are major pests in agriculture. Microbial antagonists such as nematophagous fungi are of great interest for developing alternative biocontrol strategies to replace nematicide use. This study aims to isolate, identify and assess the diversity and the in vitro predatory activity of nematophagous fungi from various olive nurseries in Morocco. A total of 305 soil samples were collected in 25 nurseries in Moroccan olive-producing areas (Jbala, Guerouane, Haouz and Souss). Seventy-three pure fungal strains from nematophagous fungi were recovered from nursery substrates infested with root-knot nematodes. Diversity indices showed that fungi were more numerous in southern regions, whereas fungal communities were more numerically alike in northern regions, partly depending on the occurrence of root-knot nematodes. One fungal strain, Talaromyces assiutensis, killed all Meloidogyne javanica juveniles during in vitro predation tests. Orbiliaceae (Arthrobotrys spp., Drechslerella brochopaga, Monacrosporium spp.) trapped 50 to 80% of juveniles. Purpureocillium and Trichoderma species killed 30 to 50% of juveniles. The diversity of nematophagous communities could be affected by the north-south climate gradient of Morocco, by their nematode prey expansion, and, to a lesser extent, by the habitat origin of the substrates used. Talaromyces assiutensis was the most efficient nematophagous species against M. javanica. The use of native nematophagous fungi is a promising alternative strategy for nematode control in olive nurseries and to prevent nematode introduction into olive orchards

Nematodes associated with saffron II: Bioindication for soil health assessment and impact of agricultural practices

International audienceHighlights: • High diversity of nematodes communities is detected in the Moroccan saffron field. • Saffron soils health are degraded in Taliouine-Taznakht regions. • Plant parasitic index (PPI) is strongly influenced by the high frequency of Traditional irrigation. • Agricultural practices are significantly impacted (MI) and (SI) indices and saffron nematodes trophic groups.Abstract: Background: Saffron cultivation is vital in the Taliouine-Taznakht regions, but the influence of agricultural practices on soil nematode communities, critical for soil health and plant productivity, is not well understood. This study characterizes nematode communities in saffron fields of the Taliouine-Taznakht regions, assessing the impact of various agricultural practices on these communities, with a focus on their diversity, functional roles, and potential as bio-indicators of soil health. A total of 163 soil samples were collected from saffron fields in Taliouine-Taznakht. Nematode communities were identified, quantified, and their functional diversity analyzed. Principal Component Analysis (PCA) was used to visualize relationships between nematode communities and sampling sites. Co-inertia analysis assessed the impact of agricultural practices on nematode diversity. The nematode communities were diverse and varied across regions. PCA identified unique nematode community compositions in different saffron fields. Omnivorous nematodes were strongly linked with Taouyalte (TA), and herbivorous ones were prevalent at Agadir Melloul (AM) and Sidi Hssaine (SH). Modern crop types, high-frequency irrigation, and alfalfa-barley rotation were positively correlated with predator nematode abundance, potentially controlling plant parasitic nematodes and encouraging nutrient cycling. Conversely, monocropping, traditional irrigation, and long plantation age correlated with reduced structure and maturity indices, suggesting a less stable ecosystem. This study unveils the intricate relationships between nematode communities in Taliouine-Taznakht saffron fields and agricultural practices. Findings indicate that specific practices, such as crop rotation and modern irrigation techniques, can foster beneficial nematode groups that improve soil health and potentially regulate harmful plant parasitic nematodes. This knowledge is crucial for crafting sustainable and effective saffron cultivation strategies