The leafminer Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato, reducing crop yields by up to 100% in greenhouses and fields, in several countries globally. Because synthetic insecticides lead to resistance and have adverse effects on natural enemies and the health of producers, alternative control methods are needed. In this study, we assessed the oviposition-deterring effect of basil plants, Ocimum gratissimum L. and O. basilicum L. (Lamiaceae), using dual-choice behavioural assays performed in flight tunnels. We found that both plants significantly reduced T. absoluta oviposition behaviour on a tomato plant located nearby. To evaluate the potential effect of basil volatile organic compounds, we formulated essential oils of both plant species in paraffin oil, and observed a similar oviposition-deterring effect. Gas chromatography analyses detected 18 constituents in these essential oils which the major constituents included thymol (33.3%), p-cymene (20.4%), γ-terpinene (16.9%), myrcene (3.9%) in O. gratissimum and estragol (73.8%), linalool (8.6%), β-elemene (2.9%) and E-β-ocimene (2.6%) in O. basilicum. Twenty and 33 compounds were identified of the volatiles collected on O. gratissimum and O. basilicum plants, respectively. The main components include the following: p-cymene (33.5%), γ-terpinene (23.6%), α-terpinene (7.2%), α-thujene (6.7%) and E-α-bergamotene (38.9%) in O. gratissimum, and methyl eugenol (26.1%), E-β-ocimene (17.7%), and linalool (9.4%) in O. basilicum. Four compounds (α-pinene, β-pinene, Myrcene, Limonene) were common in essential oils and plants. Our results suggest the valuable potential of basil and associated essential oils as a component of integrated management strategies against the tomato leafminer.

No abstract

No abstract

Various plant species contain biocidal and/or semiochemical components. These can be used for managing insect pests, in order to reduce the use of synthetic pesticides and to improve the quality of vegetable crops. This study was conducted to assess the effect of repellent plants Ocimum gratissimum L. and Ocimum basilicum L. on aphids Aphis craccivora Koch, Aphis fabae Scopoli and Myzus persicae Sulzer when they are associated with Amaranthus hybridus L. plants. The results have shown that in the two approaches tested—Ocimum sp. plants surrounded by A. hybridus plants and the dual-choice test—the number of aphids on the A. hybridus plant associated with either O. gratissimum or O. basilicum was significantly less significant compared to the A. hybridus alone. This first study on the association between A. hybridus and Ocimum spp. shows that the Ocimum species might be used as an alternative method for controlling aphids in order to avoid the use of synthetic pesticides on Amaranthus. The ability of Ocimum spp. to repel pests can make it an important companion plant for farmers, because those plants can not only be used to control pests, but they can also be harvested, providing a direct economic return.

Cet article est distribué suivant les termes et les conditions de la licence CC-BY (http://creativecommons.org/licenses/by/4.0/ deed.fr) Introduction. Les cultures maraichères occupent une place importante pour l'alimentation humaine et contribuent significativement aux revenus des familles en Afrique de l'Ouest, mais leur production est confrontée à une pression des bioagresseurs qui limite leur productivité. Littérature. Cette revue, basée sur des publications scientifiques, a pour objectif d'évaluer le potentiel des plantes pesticides comme alternative à l'usage des pesticides de synthèse pour lutter contre les bioagresseurs des cultures maraichères en Afrique de l'Ouest. Elle montre que le principal moyen actuel pour combattre ces bioagresseurs repose essentiellement sur les pesticides de synthèse. Cependant, compte tenu de leur nocivité sur l'homme et l'environnement, en plus de la sélection de populations résistantes chez les bioagresseurs, la recherche de solutions alternatives s'impose. Les plantes pesticides se présentent comme une alternative prometteuse dans le contexte ouest-africain. En effet, diverses espèces de plantes pesticides peuvent être utilisées comme extraits de plantes ou en association avec d'autres cultures pour le contrôle des bioagresseurs. Celles-ci sont présentées dans le présent article de synthèse. Conclusions. Les plantes pesticides peuvent être une alternative prometteuse pour la gestion des bioagresseurs des cultures maraichères. Cependant, la plupart d'entre elles ne sont pas cultivées. Explorer les capacités biocides de plantes d'intérêt comme le genre Ocimum, connu pour ses usages thérapeutique, médicinal et alimentaire pourrait être intéressant pour le producteur. Toutefois, les populations doivent être sensibilisées sur les avantages à long terme des produits traités avec les pesticides à base de plantes pour faciliter leur utilisation. Mots-clés. Plante pesticide, extrait d'origine végétale, culture maraichère, lutte antiravageur, Afrique au Sud du Sahara. Pesticidal plants and vegetable crop protection in West Africa. A review Introduction.Vegetable crops play a leading role in human nutrition and contribute significantly to the incomes of families in West Africa. However, their production is hampered by pressure from pests, which limits their productivity. Literature. This review, based on scientific publications, aims to evaluate the potential of pesticidal plants as an alternative to the use of synthetic pesticides to control vegetable crop pests in West Africa. It shows that the primary current method used to control these pests is mainly based on synthetic pesticides. However, in view of their harmful effects on humans and the environment, in addition to the range of resistant pest populations, the search for alternative approaches is needed. Pesticidal plants are a promising alternative in the West African context. Indeed, various species of pesticidal plant can be used as plant extracts or in association with other crops in pest management. These plants are present...

No abstract

Synthetic insecticides used for aphid control continue to be a threat to humans and the environment. Therefore, in order to reduce these problems, it is important to use less harmful, environmentally friendly agricultural practices. It is with this objective in mind that the choice behaviour of the pea aphid -Acyrthosiphon pisum Harris (Hemiptera: Aphididae -towards basil odors (Ocimum basilicum L. and Ocimum gratissimum L. (Lamiaceae)) and the broad bean -Vicia faba (Fabaceae) -was studied using a Y-tube olfactometer. Pea aphid negatively responded to basil plants and spent less time there. The repellent activity and the possibility to use basil as an aphid-repellent plant are discussed in relation to kinds of crops and local conditions.

Various plant species contain biocidal and/or semiochemical components. These can be used for managing insect pests, in order to reduce the use of synthetic pesticides and to improve the quality of vegetable crops. This study was conducted to assess the effect of repellent plants Ocimum gratissimum L. and Ocimum basilicum L. on aphids Aphis craccivora Koch, Aphis Prime Archives in Agronomy 3 www.videleaf.com fabae Scopoli and Myzus persicae Sulzer when they are associated with Amaranthus hybridus L. plants. The results have shown that in the two approaches tested-Ocimum sp. plants surrounded by A. hybridus plants and the dual-choice test-the number of aphids on the A. hybridus plant associated with either O. gratissimum or O. basilicum was significantly less significant compared to the A. hybridus alone. This first study on the association between A. hybridus and Ocimum spp.shows that the Ocimum species might be used as an alternative method for controlling aphids in order to avoid the use of synthetic pesticides on Amaranthus. The ability of Ocimum spp. to repel pests can make it an important companion plant for farmers, because those plants can not only be used to control pests, but they can also be harvested, providing a direct economic return.