Geographical distribution and prevalence of the main tomato fungal wilt diseases in Benin

Tomato is one of the most economically important vegetable crops in Benin and its production represents more than 51% of the total production of vegetable crops. The ecological peculiarity of its farming exposes it to diseases and pests. Tomato wilt constitutes the major phytosanitary constraint for its production. To identify the causal agents, a survey was carried out across the 12 departments of Benin. Three districts were selected per department and three villages in each district were surveyed. Two farmer’s fields were visited per village where five diseased plants were collected per field. Three pathogens identified from the samples  collected in the diseased fields: Sclerotium rolfsii, Fusarium oxysporum f. sp. lycopersici and F. solani. Pathogenicity test conducted for each of the isolated  pathogens was positive. The symptoms observed in greenhouse were exactly the same as those recorded in the field. The prévalence of tomato wilting recorded in farmer’s fields varies from 0.1% to 27% for S. rolfsii, from 3% to 20% for F. oxysporum f. sp. lycopersici, and from 1% to 3% for F. solani. The most  disseminated and most devastating pathogen was S. rolfsii. F. oxysporum f. sp. lycopersici and F. solani were less disseminated and less devastating pathogens.Keywords: Tomato, fungal wilts, incidence, distribution, Bénin

Efficacite de l’hydroxyde de cuivre contre la nervation noire du chou (Brassica oleracea l.) Causee par la bacterie xanthomonas campestris pv. Campestris

Pour tester l’efficacité de l’hydroxyde de cuivre contre la nervation noire du chou, des expérimentations ont été conduites sur le site maraîcher de Houèto (commune d’Abomey-Calavi), au cours desgrande et petite saisons de pluies de l’année 2013. Le dispositif de bloc aléatoire complet dispersé à quatre répétitions et cinq traitements a été utilisé. Les parcelles témoins, traitées avec l’oxyde de cuivre 1 kg/ha et avec l’hydroxyde de cuivre aux doses de 2,25 kg/ha, 3 kg/ha et 4,5 kg/ha étaient les traitements à comparer. La sensibilité de Xanthomonas campestris pv. campestris (Xcc) à l’hydroxyde de cuivre, l’incidence et la sévérité de la nervation noire du chou étaient les paramètres évalués au cours des expérimentations. La bactérie Xcc a été positivement confirmée. Pendant la grande saison de pluies, la sévérité a été significativement faible dans les parcelles traitées avec l’hydroxyde de cuivre aux doses de 3 kg/ha (7,11 %) et 4,5 kg/ha (7,09 %). Par contre, en petite saison de pluies, la maladie s’était faiblement manifestée sur tout le site expérimental avec une sévérité inférieure à 0,05 %. L’incidence était aussi plus élevée au cours de la grande saison de pluies (79,6 % à 82,5 %) comparée à la petite saison de pluies (0,9 % à 1,6 %). Les doses de 3 kg/ha et 4,5 kg/ha d’hydroxyde de cuivre ont été les plus efficaces contre la nervation noire du chou.Mots clés : Nervation noire du chou, hydroxyde de cuivre, efficacité, Xanthomonas campestris pv. campestrisEnglish abstractEfficiency of copper hydroxide on cabbage (Brassica oleracea l.) Black rot caused by xanthomonas campestris pv. CampestrisTo test the efficiency of copper hydroxide against the cabbage black rot, trials were conducted on the garden site of Houeto village (Abomey-Calavi), during the big and the short rainy seasons in 2013. The randomized complete block design with four repetitions and five treatments have been used. Untreated control plot, plot treated with copper oxide at 1 kg/ha and plots treated with copper hydroxide at 2.25 kg/ha, 3 kg/ha and 4.5 kg/ha were the five considered treatments. The susceptibility of Xanthomonas campestris pv. campestris (Xcc) to the copper hydroxide, the incidence and the severity of cabbage black rot, were the evaluated parameters during the two trials. Xcc was positively confirmed. During the big rainy season, the severity was significantly low in plots treated with copper hydroxide at 3 kg/ha (7.11 %) and 4.5 kg/ha (7.09 %). While during the short rainy season, the disease was weak in the whole experimental site with a severity varying between 0.02 % and 0.03 %. The incidence was also high during the big rainy season (79.6 % to 82.5 %) and weak during to the short rainy season (0.9 % to 1.6 %). The doses of 3 kg/ha and 4.5 kg/ha of copper hydroxide were efficient on cabbage black rot.Key words : Cabbage black rot, copper hydroxide, efficiency, Xanthomonas campestris pv. campestri

Olfactory responses of Sitophilus zeamais L. to bushmint leaf powder and methanol extract on stored maize

Bushmint ( Hyptis suaveolens Poit) is a weed with pesticidal properties that have been explored in managing pests of agricultural and medicinal importance. The objective of this study was to evaluate the repellence ability of Hyptis suaveolens to prevent infestation of stored maize grain seed. The study involved evaluation of the olfactory responses of adult weevil to maize ( Zea mays L.) grains treated with 5, 10, 15 and 20% concentrations of leaf powder (LP) and methanol extract (ME) of Hyptis suaveolens in the laboratory, with a static air four-chamber olfactometer. Also, the insecticidal effects of the substances on adult mortality and oviposition on maize grains treated with LP and ME were determined in a completely randomised design, with four replicates. The number of weevils in ME chambers decreased with increase in concentration of extracts; while the LP chambers had consistently fewer weevils with numbers, ranging from 2.5 to 3.75. Adult mortality in maize treated with LP was the least and varied between 0.00 (15% concentration) and 2.54% (20% concentration). Maize grains with ME caused significant mortalities that ranged from 65.50% at 15% concentration to 94.92% at 10% concentration. More eggs (3.5 to 5.75) were laid on maize with LP compared with ME treated maize. Generally, ME was richer in phytochemicals than LP. Hyptis suaveolens repellence manifested more in the form of LP than as ME; though ME caused more adult mortality and reduced oviposition than LP.La menthe de brousse ( Hyptis suaveolens Poit) est une adventice aux propri\ue9t\ue9s pesticides explor\ue9es dans la gestion des ravageurs en agriculture et en m\ue9dicine. Bien que des donn\ue9es sur son efficacit\ue9 contre les ravageurs de stocks soient disponibles, sa capacit\ue9 r\ue9pulsive contre les insectes de stocks n\u2019a pas \ue9t\ue9 suffisamment document\ue9e. Par cons\ue9quent, les r\ue9ponses olfactives du charan\ue7on du ma\uefs en stock trait\ue9 avec des concentrations de 5, 10, 15 et 20% de poudre de feuilles d\u2019H. suaveolens (LP) et de son extrait m\ue9thanolique (ME) ont \ue9t\ue9 \ue9tudi\ue9es au laboratoire \ue0 l\u2019aide d\u2019olfactom\ue8tre \ue0 quatre compartiments \ue0 air statique. De m\ueame, les effets insecticides des substances sur la mortalit\ue9 des adultes et la ponte sur les grains de ma\uefs trait\ue9s avec LP et ME ont \ue9t\ue9 d\ue9termin\ue9s suivant un dispositif compl\ue8tement al\ue9atoire \ue0 quatre r\ue9p\ue9titions. Le LP et le ME ont \ue9t\ue9 analys\ue9s pour leurs compos\ue9s phytochimiques. Le nombre de charan\ue7ons dans les compartiments ME diminuait avec l\u2019augmentation de la concentration d\u2019extrait, tandis que les compartiments LP avaient constamment moins de charan\ue7ons avec des nombres variant entre 2,5 \ue0 3,75. Le pourcentage de mortalit\ue9 d\u2019adultes dans le ma\uefs trait\ue9 avec LP \ue9tait le plus faible et variait entre 0,00 (concentration 15%) et 2,54% (concentration 20%). Le ma\uefs trait\ue9 avec ME causait des mortalit\ue9s significatives allant de 65,50% pour une concentration de 15% \ue0 94,92% pour 10% de concentration. Le nombre le plus \ue9lev\ue9 d\u2019\u153ufs (3,5 \ue0 5,75) a \ue9t\ue9 pondu sur du ma\uefs trait\ue9 avec LP, tandis que le nombre le plus faible (1,0) a \ue9t\ue9 enregistr\ue9 sur celui trait\ue9 au ME. Des concentrations significativement \ue9lev\ue9es de compos\ue9s phytochimiques \ue9taient obtenues dans ME comparativement \ue0 LP. Le ma\uefs trait\ue9 avec LP \ue9tait hautement r\ue9pulsif pour Sitophilus zeamais, tandis que celui trait\ue9 avec ME causait la mortalit\ue9 des adultes et r\ue9duisait la ponte

Integrated pest management in vegetable production: a guide for extension workers in West Africa

Indigenous and exotic vegetables are central to most nutrition, food security and poverty reduction programmes around the world. However, in most of West Africa, the economic opportunities offered by vegetables are often undermined by production and trade constraints (i.e. pest damage, inappropriate pesticide usage, absence of environmental safeguard policies and/or stringent food safety standards). Extension workers and, in places, farmers groups and local community organizations, are working towards helping farmers to increase their yields in sustainable ways that create wealth and reduce the risks to productivity. All too often, extension workers do not know the cause of common pest problems in the crops they work with. Pest problems usually arise when the biological, ecological and sociological processes which underpin agriculture are disrupted. This guide helps to fill that information gap. It is one of many responses by the International Institute of Tropical Agriculture (IITA) which enables such workers to develop and use technologies. It focuses on accurate identification and better understanding of biodiversity in the development and application of Integrated Pest Management (IPM) options against vegetable pests. IPM is a knowledge-intensive approach to enhance profitability of agricultural systems, while minimizing threats to human health and the environment. The technical knowledge and skills in this guide can be used to look for, develop and apply effective vegetable IPM options. The IPM options outlined here are in harmony with the environment, sustainable, simple to apply, and cheap to maintain. The guide addresses IITA’s strategic aim of increasing the quality and usefulness of IPM research in support of reducing food security and poverty. It draws heavily on IITA’s experiences in Africa, with a particular emphasis on vegetable agroecosystems in Benin. Given the substantial economic costs of pest infestations in vegetable agroecosystems, the use of this guide in Africa is expected to improve incomes and overall agricultural productivity in the long-term. Peter Hartmann Director General International Institute of Tropical Agriculture March 2010 ForewordThis guide has been produced by the International Institute of Tropical Agriculture (IITA) and Institut National des Recherches Agricoles du Bénin (INRAB), Cotonou, Benin, with support from the CGIAR Systemwide Program on Integrated Pest Management (SP-IPM), to improve the quality and usefulness of pest management research. This publication was part funded by the ACP-EU Technical Centre for Agricultural and Rural Cooperation (CTA)

First report of Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) in the Republic of Benin

Open Access Journal; Published online: 24 Oct 2018Tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a serious pest of tomato Solanum lycopersicum L. (Solanaceae) originating from South America. Due to previous outbreaks in neighbouring West African countries, surveillance was ongoing since 2014 in Benin. Tomato plants were regularly inspected and pheromone traps placed in tomato-producing localities in northern, southern and central Benin, including fields close to the border with Niger and Nigeria. In late 2017 and beginning of 2018 Gelechiidae moths were obtained from both the traps and the reared plant material. Morphological examination and molecular analysis of the gained specimens allowed to confirm the presence of the pest in the northern and central regions of Benin. We hence confirm the presence of T. absoluta in yet another West African country

Effets des rhizobactéries PGPR sur le rendement et les teneurs en macroéléments du maïs sur sol ferralitique non dégradé au Sud-Bénin

L’objectif de l’étude est d’évaluer les effets de 15 rhizobactéries promotrices de croissance végétative (PGPR en Anglais) sur le rendement et l’état nutritionnel des plants de maïs sur sol ferralitique non dégradé du Sud-Bénin. Les semences de maïs ont été inoculées avec des concentrations microbiennes d’environ 108 UFC/ml. Les teneurs en azote, en phosphore et en potassium d’échantillons de plants de maïs ont été déterminées. Les valeurs de rendement du maïs ont été soumises à une analyse de la variance à deux facteurs. Les rhizobactéries Pseudomonas fluorescens ont induit le rendement de maïs le plus élevé, dépassant de 41,46% le rendement de maïs obtenu avec l’inoculation de P. putida et de 118,05% le rendement de maïs obtenu au niveau des plants non inoculés. Les rendements de maïs induits par P. putida et Azospirillium lipoferum sont supérieurs respectivement de 54,17% et de 26,39% au rendement obtenu au niveau des plants non inoculés. Les résultats obtenus augurent de la possibilité d’utiliser les rhizobactéries PGPR comme des engrais biologiques pour une production durable de maïs. Au Sud du Bénin, où la pression démographique est forte et la baisse de la fertilité des sols croissante, l’utilisation de méthodes biologiques pour accroître les récoltes est une solution incontournable.Mots clés: Rhyzobactéries, Rendement, Maïs, Sol ferralitique, Béni

Gestion intégrée des nuisibles en production maraîchère : Guide pour les agents de vulgarisation en Afrique de l'Ouest

Les parasites se manifestent généralement en cas de bouleversement des processus biologiques, écologiques et sociologiques qui sous-tendent l'agriculture. En plus d'apporter des informations sur la gestion durable des menaces biotiques portées à une production végétale saine, ce guide suggère également des manières d'enseigner et de diffuser des pratiques de lutte antiparasitaire intégrée auprès d'un public plus large. Exceptionnellement bien illustré par des illustrations, tableaux et photos, cet ouvrage se promet d'être une référence précieuse pour les professionnels sur le terrain, les agents de vulgarisation, les techniciens, les étudiants et les scientifiques

Screening African rice (Oryza glaberrima) for tolerance to abiotic stresses: I. Fe toxicity

AbstractIron (Fe) toxicity is recognized as one of the most widely spread soil constraints for rice production especially in West Africa. Oryza glaberrima the cultivated rice species that originated from West Africa is well-adapted to its growing ecologies. The aim of this study was to identify the promising O. glaberrima accessions tolerant to Fe toxicity from the 2106 accessions held at the AfricaRice gene bank. The screenings were conducted over a four-year period and involved evaluating the entries under Fe-toxic field conditions in West Africa, selecting good yielding accessions and repeating the testing with newly selected lines. Three accessions (TOG 7206, TOG 6218-B and TOG 7250-A) were higher yielding than O. sativa checks under stress but with similar yields under control conditions. These accessions yielded over 300g/m2 under both Fe toxicity and control conditions. In conclusion, these materials could be used as donors in breeding programs for developing high yielding rice varieties suited to Fe toxicity affected areas in West Africa

Re-assessing the pest status of Tetranychus evansi (Acari: Tetranychidae) on solanaceous crops and farmers control practices in Benin

Open Access Journal; Published online: 24 Sep 2022This study was carried out 7 years after a first one conducted in 2013 as part of the policy of the Benin government to promote the vegetable production sector. Data collection was mostly based on a countrywide survey conducted in 25 municipalities throughout Benin, from August to December 2020. Farmers were selected based on their experience in cultivating solanaceous crops, and were interviewed to assess their perception about the severity of the spider mite Tetranychus evansi, the control method they used against this pest, and their knowledge about potential predators associated with the mites. Additionally, predatory mites associated with T. evansi in farmer fields were identified. All farmers recognized T. evansi to which they attributed local names depending on their ethnic group. They were also able to identify its damages on solanaceous crops. They indicated that outbreaks of T. evansi occurs at the end of the rainy season while their damages are more severe during the dry season. Production losses due to the mites were estimated by farmers to 27%, 24% and 22% respectively for tomato, African eggplant, pepper in the moderate damage case and 80%, 79%, 55% respectively for tomato, African eggplant and pepper in the severe damage conditions. To fight the mites, farmers generally apply heavy doses of chemical pesticides at high frequency. Pyrethroid and organophosphate compounds are the most frequently used pesticides. The only phytophagous mite recorded was T. evansi. A total of four species of predatory mites, all belonging to the phytoseiid family, were found associated with the pest on Solanaceous plants: Amblyseius swirskii, A. tamatavensis, Neoseiulus barkeri and N. longispinosus. This is the first report of the presence of N. longispinosus in Benin. Considering the high losses attributed to the pest, effective and sustainable management practices are necessary

Effet De La Technologie, Du Cultivar Et De La Durée De Conservation Sur La Stabilité Et La Qualité Du Lait De Soja (Glycine maxima)

Three technologies named D (wet dehulled soybeans seeds), B (boiled soybean seeds before dehulling) and T (roasted soybean seeds before dehulling) for stabilized soymilk production were tested with TGX (large grain size) and Jupiter (small grain size) cultivars. Production yields, sensory, physicochemical and microbiological characteristics of produced milks were determined over a period of 3 months. . The bottled milk was sterilized at a temperature of 115°C under a pressure of 0.7 bar for one hour. The milks were stored at temperature storage place 27°C (for 3 months). The milk yield for technology D is 90.87 % for the jupiter and 92.01 % for the TGX. These yields are higher than the other technologies. Whatever the technology, the TGX cultivar gives a better yield 92.01 %. Sensory analysis revealed that the milk produced with technology D and jupiter cultivar is more appreciated by the 77 % panelist. This milk has a pH of 7.14 at the day of production and decreases to 6.83 after 3 months of storage. Protein, fat and Dry Soluble Matter (DSM) content decreased after storage by 4.30 to 4.13 %, 1.7 to 1.2 % and from 11.68 to 10.28 °Brix respectively. The viscosity was 1.24 cp at the beginning and 1.38 cp after storage. After 3 months of storage, the milk is stable and its microbiological quality complies with accepted standards in relation to spores, coliforms, yeasts and molds