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The oriental fruit fly (Bactrocera dorsalis) is one of the world's most invasive and polyphagous fruit pests. It causes severe damage throughout its range and can devastate the entire fruit harvest in unprotected orchards. In 2007, B. dorsalis was detected in Mayotte, where it now ranks ninth on the list of fruit fly species of economic importance. This tropical island is a good study area to analyse the host range of B. dorsalis and its interactions with other resident fruit fly species. Two field campaigns were carried out from 2012 to 2014 and from 2019 to 2021. We collected fruit from all over the island in cultivated and non-cultivated areas and compared the infestation rates between the two periods. We detected six fruit fly species, including the common species Dacus ciliatus, Neoceratitis cyanescens, Ceratitis capitata, B. dorsalis and two rarer species, Dacus etiennellus and Trirhithrum nigerrimum. The most surprising result was the low occurrence of B. dorsalis, with only seven host plant species identified out of a total of 84 plant species. Infestation rates were low for these host plant species, even in the case of mango (11.71 flies/kg) and Indian almond (0.97 fly/kg), which are considered to be major host plants of B. dorsalis. Bactrocera dorsalis seems to have a lower impact in Mayotte than in other parts of the world. We discuss the possible causes of the weak infestation rates observed, which could provide the key to regulating the species on the island.

The grafting technique has successfully mitigated crop losses from diseases and stress in vegetable production; however, vegetable grafting in Tanzania is very limited. Field and greenhouse experiments conducted in Tanzania's mainland and islands compared the response of tomato determinate cv. 'Tanya' to production challenges when ungrafted and grafted onto five tomato rootstocks ('Hawaii 7796', 'Tengeru 1997', 'Tengeru 2010', 'R3034', and 'Shelter'), one eggplant variety ('EG 203'), and one wild Solanum species (Solanum elaeagnifolium). The visual symptoms of bacterial wilt varied significantly with location and season, ranging from 8 to 100%, attributed to varying bacterial wilt pressures and strains of Ralstonia solanacearum isolated (Phylotype I sequevars 17, 18, and 31). 'EG203' and 'Hawaii 7796' emerged as the most effective rootstocks, reducing wilting by 49.8 and 51.0% and improving yield by 57.2% and 27.7% on average across experiments conducted in three locations (Moshi, Pemba, and Unguja) over two seasons. Combining reduced water supply with grafting resulted in an average reduction in wilting of 76%, while also boosting yields by an average of 3.6 times in experiments conducted in Arusha over two seasons. Grafting onto 'Hawaii 7796' and 'Shelter' significantly improved 'Tanya' yields by 38.3% and 41.6% on average over two seasons, only under standard nutrient application rates. While certain rootstocks improved crop performance, yields across various sites and seasons were significantly hampered by pest pressure. These findings support grafting's potential to mitigate damage from common stresses, emphasizing the need for further research to identify suitable rootstocks for optimizing returns on investments in grafted plants in Tanzania.

Natural pest regulation is a key ecosystem service to achieve agroecological intensification. However, its routine integration to pest management strategies is pending because of its unpredictability, hampering the trust of producers to rely on this service. To reduce this knowledge gap and increase foresight of natural pest regulation in production systems, we studied its drivers in vegetable crop fields in La Réunion, a tropical island in the Indian Ocean. We selected and characterized 20 fields representing the diversity of the grown crops, surrounding habitats, management practices and seasonality of the island. We then assessed the plant and arthropod communities associated with the crop and its margins using quadrats and non-selective interception and pitfall traps. We also observed the presence of pests and their natural enemies on the crop, whilst measuring crop damages and yield. Finally, the surrounding landscape was described at the short scale (within 500m) through GIS. Results demonstrated the strong relation between plant diversity and arthropod diversity, with subsequent consequences on pest abundance and pressure. Effects of the management practices and the landscape on these interactions were highlighted and discussed. Aside increased knowledge concerning systemic pest regulation mechanisms, this study opens the discussion on the utility of the development of bioindicators of these services. Such tools are expected to help stakeholders to further mobilize and integrate these services in their management strategies.

Dans le cadre du plan gouvernemental de réduction de l'usage des pesticides, deux projets, Ecophyto DEPHY EXPE ALTO (France métropolitaine) et STOP (Ile de La Réunion), expérimentent des systèmes horticoles diversifiés dans l'objectif de produire sans pesticides de synthèse, en s'appuyant sur la biodiversité. Les performances des systèmes diversifiés sont plurielles et aucune méthode n'est disponible pour évaluer ces types de systèmes horticoles. Une démarche participative impliquant différents acteurs de la filière a permis la construction d'un cadre de restitution des résultats sous forme de “feuillets résultats” accessibles et appropriables par les agriculteurs. Ce cadre tient compte des spécificités de ces systèmes diversifiés agroécologiques en proposant une représentation des performances des systèmes diversifiés dans leur complexité, en regard de leur contexte, de l'occupation des espaces et de leur variabilité temporelle. Ce travail se poursuit pour intégrer d'autres volets à l'évaluation dont le pilotage de ces systèmes diversifiés.

In sub-Saharan Africa (SSA), agricultural data are often scarce, irregular, unreliable, and inaccessible. Agricultural data, when existing, relate almost exclusively to yields and cultivated areas at the national level and SSA suffers a significant lack of information at sub-national levels describing the agricultural systems (area, production quality and quantity, management practices, agrobiodiversity). This study focused on horticultural crops (fruits and vegetables) for which the situation of data are worse than for annual staple crops because: i) fewer studies are carried out on horticultural crops; and ii) the complexity of horticultural systems hampering the development of accurate assessment methods. Despite the importance of fruits and vegetables for food security, it is acknowledged that the lack of horticultural data in SSA affects all stakeholders of the value chains – from farmers to the national and international institutions. We focused on digital agriculture, which relies on technologies, as one of the pathways for data improvement in SSA by supporting data acquisition, standardisation, availability, and sharing between stakeholders. For instance, data acquired by participative monitoring using smartphones might increase the availability of accurate information on yields at the field scale. Other examples have shown that remotely sensed data from drones or satellites allow to accurately map and monitor horticultural systems, including agroforests. By overcoming the lack of data, digital agriculture can help to better characterise and evaluate horticultural systems to improve food security. The robustness of these tools and their adoption by farmers are discussed to upscale digital agriculture to address food security issues in SSA.

Alors que l'économie circulaire (EC) comme nouveau paradigme économique et sociétal émerge, la place du secteur agricole dans les initiatives d'accroissement de la circularité dans les territoires est questionnée. Ce questionnement est d'autant plus pertinent dans un contexte insulaire comme celui de La Réunion, où les enjeux d'autonomie alimentaire et énergétique sont majeurs. De 2017 à 2020, un projet de Recherche et Développement intitulé GABiR (Gestion Agricole des Biomasses sur l'île de La Réunion) a mobilisé des acteurs issus du Développement, de la Formation et de la Recherche, dont de nombreux agronomes de diverses disciplines, mais également des décideurs politiques. Ce projet visait à renforcer l'inclusion du secteur agricole dans l'EC de l'île par une approche territoriale de la gestion des biomasses, valorisées ou valorisables en agriculture. Fort de cette expérience et des acquis du projet, un cadre méthodologique à visée générique relevant d'une démarche clinique à l'échelle territoriale et visant à accompagner la transition vers une EC incluant le secteur agricole est proposé.

Numerous studies have highlighted the merits of grafting to improve the performance of vegetable crops. However, the technique is hindered by several obstacles, including the synchronization of seedlings used as scions and rootstocks, and the effects of rootstocks and climatic conditions on grafting success rates. This study sought to gain insights into how such technical obstacles affect tomato grafting. An initial experiment conducted in a greenhouse set out to assess the relevance of using degree-days to predict the growth rates of seedlings used for grafting (i.e., stem diameters above cotyledons). The success rate for grafting a tomato variety (Tanya) on 10 different rootstocks from different species—namely tomato, eggplant, african eggplant, and a wild species—was assessed at different temperatures (i.e., 15, 20, 25, 30, 35, and 40 °C). The effects of grafting on plant vigor (i.e., fresh biomass), number of leaves, and plant height, and on the hydraulic conductivity of xylem vessels in the plant stem were assessed 2 weeks after grafting. The results show the advantage of using degree-days to predict the ready-to-graft stage of seedlings, as it reduced the discrepancy among trials. The grafting success rate was more than 90% at 15 and 20 °C, but decreased significantly with higher temperatures, down to 20% at 40 °C. Larger variations in growth rate for seedlings used as scions and rootstocks, a lower grafting success rate, and less vigor were recorded for heterografted plants than for homografted plants. The lower hydraulic conductivity measured in the stems of grafted plants, especially heterografted plants, was consistent with the lower plant vigor observed. Further studies are needed to investigate how grafting affects the hydraulic conductivity of xylem vessels in later developmental stages of grafted plants.

This paper presents data collected in 2013, 2014 and 2015 on the cultural practices and agronomic performance of cropping systems in 500 lowland rice fields located in five regions of three West African countries, Benin, Mali and Sierra Leone. Data were collected in two stages. In the first stage, the main regions containing inland valleys were identified in each of the three countries and the most cultivated inland valley in each region was selected. Weather data were obtained from weather stations located close to the selected inland valleys. In regions with no weather stations, Tinytag data loggers were installed in the inland valleys to collect data on temperature, rainfall and relative humidity. In the second stage, the location and size of all the farmers' fields in each inland valley were determined using GPS devices. In 2013, soil samples were collected in each farmer's field and the soil physical-chemical properties were determined. Agronomic and socio-economic surveys were conducted to collect data on cultivated crops, crop sequences and management techniques using questionnaires and informal interviews. Crop yields were determined in each farmer's field in the growing season. The database contains a total of 131 variables divided into 9 themes: field characteristics, land preparation, field maintenance, irrigation, residue management, soil data, weather data, crop productions in the dry season and crop production in the rainy season.

In sub-Saharan Africa, unexploited land and water resources in wetlands represent an important potential for intensified, sustainable and food-secure farms through rice production and market gardening. The lack of uptake of cropping in wetlands may be related to the ways in which resources are divided between family fields and individual fields. The management system on sub-Saharan African farms comprises a family management unit or a combination of a family management unit and one or more individual management units. The family management unit or the farm head controls production in family fields to satisfy family needs while the individual management units control production in individual fields to satisfy individual needs. Our objective was to investigate the diversity in farm management systems and the resulting uptake of cropping in wetlands for different farm types, as the first step towards suggestions for enhancing rice production and market gardening in wetlands. We studied farms in two case-study villages in Benin: Zonmon in the southern part and Pelebina in the north-western part. Farm typologies were developed based on random samples of 51 out of 134 farms (38%) from Zonmon and 50 out of 146 farms (34%) from Pelebina by combining principal component analysis and Ward's minimum variance clustering. Variables included in the PCA were related to levels of resource endowment (e.g., amounts of land, family labour, cash for purchasing chemical inputs and hiring labour) and to resource-use strategies including resource division between family fields and individual fields, and between uplands and wetlands. We identified 3 farm types in Zonmon and 5 farm types in Pelebina based on differences in resource-use strategies and in resource endowment. We found no trade-off between the existence of individual fields and the area under rice and market garden crops in wetlands. Labour abundance was the main factor driving both the occurrence of individual fields and the e