Perception des producteurs de banane (Musa spp.) sur la maladie du bouquet au sud du Benin

La maladie du bouquet du bananier constitue une contrainte majeure à la production en quantité et en qualité des bananes au Bénin. Le présent  travail rapporte les connaissances des producteurs quant à la manifestation de la maladie et les méthodes de gestion utilisées. Des prospections  ont été effectuées dans trois zones agroécologiques au sud du Bénin sur des critères spécifiques avec 627 producteurs identifiés et interrogés  quant à leur connaissance de la maladie, les causes et les méthodes de contrôle. L’analyse des données a montré que bien que connaissant la  maladie, ils n’en maîtrisent généralement pas les causes (59,17 %). Cependant quelques causes telles que le mauvais entretien des champs (25,68  %), le matériel végétal (9,80 %) ainsi que les insectes et les champignons (5,26 %) ont été énumérées. Bien souvent, leurs connaissances varient  d’une zone à une autre. Quant aux mesures de contrôle, la plupart coupent les plantes infectées (77,73 %), les uns déracinent (18,97 %) et les autres  utilisent les herbicides (3,22 %). Cette étude révèle une subtilité autour de la connaissance de la maladie dans les trois zones agroécologiques au  niveau des producteurs. English title: Banana (Musa spp.) producers’ perception on banana bunchy top disease in southern Bénin Quantity and quality Banana production in Benin is limited by several factors including the viral disease named bunchy top disease (BBTD). The  objective of this study is to evaluate the knowledge of producers on the disease and the factors influencing its prevalence. To reach this goal,  surveys were conducted in three southern agro-ecological zones (zone 6, 7 and 8) of Benin. Six hundred and twentyseven producers were randomly  considered and interviewed on their knowledge on BBTV, its causes and control methods. Data analysis showed that farmers’ perception on BBTD  varies from one zone to another. The majority of farmers are aware of the disease but ignore the causal agent (59.17%). While 9.80% reported that  planting material is responsible of the disease, 25.68% cited the lack of field maintenance and for others (5.26%), insects and fungi are responsible  of the disease. For control strategies, as for control methods, decapitation is the most adopted (77.73) by farmers followed by uprooting (18.97%)  and herbicide injection (3.22). This study reveals the complexity of BBTV perception in the three agro-ecological zones at producer level

Efficacité d’extraits botaniques et de Cydim Super dans la lutte contre la cochenille (Dysmicoccus brevipes) associée à la maladie du wilt chez l’ananas

Cydim super et les extraits aqueux du piment (Capsicum frutescens), du neem (Azadirachta indica) et d’hyptis (Hyptis suaveolens), ont été testés dans un dispositif de bloc de Fisher pour leur efficacité à contrôler la cochenille farineuse (Dysmicoccus brevipes) de l’ananas (Ananas comosus). Les essais ont été conduits avec cayenne lisse au champ à Loto-Dénou, Allada en conditions d’infestation naturelle et dans la serre à l’Institut International d’Agriculture Tropicale station du Bénin où les cochenilles ont été multipliées sur les fruits de potiron pour être lâchées à raison de 20 insectes par plant avant la pulvérisation des produits. Après application des produits, la densité des cochenilles a chuté dans toutes les parcelles sauf les parcelles témoins. Les parcelles traitées avec Cydim super ont montré la densité la plus basse (0, 288) significativement différente des autres au seuil de 5% (Duncan multiple Range Test) suivi de l’extrait de Hyptis suaveolens (0,905) pour atteindre 0 et 0,047 respectivement. Les parcelles témoins ont donné plus de fruits affectés par le wilt que les autres. En serre, Cydim super a été aussi le produit le plus efficace avec une moyenne de 18,60 cochenilles mortes, suivi de hyptis avec un nombre moyen d’insectes morts de 9,20.Mots clés : Extraits-aqueux, piment, neem, hyptis, insecticide, virus

Response of cassava cultivars to African cassava mosaic virus infection across a range of inoculum doses and plant ages

Open Access Journal; Published online: 23 Dec 2019Cassava production in Africa is constrained by cassava mosaic disease (CMD) that is caused by the Cassava mosaic virus (CMV). The aim of this study was to evaluate the responses of a range of commonly cultivated West African cassava cultivars to varying inoculum doses of African cassava mosaic virus (ACMV). We grafted 10 cultivars of cassava plants with different inoculum doses of CMV (namely two, four, or six CMD-infected buds) when the experimental plants were 8, 10, or 12 weeks old, using non-inoculated plants as controls. Three cultivars showed disease symptoms when grafted with two buds, and four cultivars showed disease symptoms when grafted with four or six buds. Most cultivars became symptomatic six weeks after inoculation, but one (‘TMS92/0326’) was symptomatic two weeks after inoculation, and two (‘Ntollo’ and ‘Excel’) were symptomatic after four weeks. Root weight tended to be lower in the six-bud than in the two-bud dose, and disease severity varied with plant age at inoculation. These results indicate that the level of CMD resistance in cassava cultivars varies with inoculum dose and timing of infection. This will allow appropriate cultivars to be deployed in each production zone of Africa in accordance with the prevalence of CMD

Adoption of roguing to contain banana bunchy top disease in south-east Benin: role of farmers' knowledge and perception

Published online: 26 Oct 2019Banana bunchy top disease (BBTD) caused by Banana Bunchy Top Virus (BBTV) has emerged as a major constraint of banana and plantain production in south-East Bénin. Roguing method is used in this area to destroy the BBTV-infected plants and to contain its spread. This study was conducted to assess the level of adoption of the method in relation to farmers’ perception. The research was conducted in eight communities and data collected from 186 randomly selected banana growers. Farmers’ perception on the roguing method as compared to traditional practices was analyzed using an aggregated perception index. The counterfactual method based on Average Treatment Effect was used to estimate adoption rates and determine the factors influencing adoption. Results showed that roguing is perceived to provide more advantages than traditional practices, but it is often time consuming and very labor demanding. The actual adoption rate is 36%. It would have been 56% if all the growers sampled were sensitized. As a matter of fact, the majority (73%) of sensitized growers adopted the method. More efforts and resources should be put into sensitizing and mobilizing farmers on the adoption of this technology while improving its efficiency and taking account the shortcomings reported by farmers. This, coupled with an increase in easy access to healthy planting materials and use of good production practices could improve the adoption of roguing and consequently ensure the effective containment of BBTD

Resistance of F1 segregating populations derived from crosses between wild banana accessions Musa acuminata spp. burmannicoides Calcutta 4 and M. balbisiana Montpellier to black leaf streak disease

Banana ranks among the four most important crops in the developing world. A significant proportion of world production is also imported and consumed in developed nations. Mycosphaerella leaf spot diseases caused by Mycosphaerella species are major threats to banana production. Breeding for resistance is the most sustainable approach to controlling Mycosphaerella leaf spot diseases for which an understanding of the genetics of plant resistance and the genetic diversity of the pathogen is required. The most common Mycosphaerella leaf spot disease in Nigeria is black leaf streak caused by M. fijiensis. A Nigerian isolate of M. fijiensis was used to assess the resistance of segregating populations of selfed Musa acuminata ssp. burmannicoides (‘Calcutta 4’) and also M. acuminata spp. burmannicoides ‘Calcutta 4’ × M. balbisiana ‘Montpellier’. The results showed that resistance is quantitative. Using Punnett squares, the resistance in wild diploid species and the variable levels of susceptibility in major triploid cultivars, including dessert banana (AAA), plantain (AAB) and cooking banana (ABB), was simulated and explained. Finally, investigations on the identity of the ancestral parents of the AAB-genome plantain cultivars, AAA-genome East African highland banana cultivars and ABB-genome cooking banana cultivars are proposed for better resistance breedin

Prevalence De La Maladie Du Deperissement De L’ananas (Wilt) Et Perception Des Producteurs Au Benin

Pineapple [Ananas comosus (L.) Merril], cultivated in Benin for it economical importance is affected by Pineapple mealybug wilt, a viral disease. The objectives of this study were to evaluate the determining factors of its prevalence and farmers knowledge on the disease. To achieve these, a total number of 180 farmers, distributed in five communes of southern Benin have been interviewed in 2014 and 2015. In order to identify factors that influence the disease distribution, generalized linear models with the binomial and multinomial distribution family were used to explain the effect of the variables (field and plant levels) and disease severity, respectively. Only factors ‘commune’ 'and' year ' had a significant effect on the incidence at field level (69% in 2014 and 78% in 2015) while three predictors (township, year and variety) explained the severity of the disease and the interaction year -township was significant. Farmers perceive the disease and attribute five causes responsible for its expression. They use height methods to manage the disease. These findings constitute a qualitative as well as quantitative information to build on in designing methods of controlling the disease in order to boost the productivity of pineapple in Benin

Pathogenic variation of Mycosphaerella species infecting banana and plantain in Nigeria

Mycosphaerella species that cause the ‘Sigatoka disease complex’ account for significant yield losses in banana and plantain worldwide. Disease surveys were conducted in the humid forest (HF) and derived savanna (DS) agroecological zones from 2004 to 2006 to determine the distribution of the disease and variation among Mycosphaerella species in Nigeria. Disease prevalence and severity were higher in the HF than in the DS zone, but significant (P < 0Æ001) differences between agroecological zones were only observed for disease severity. A total of 85 isolates of M. fijiensis and 11 isolates of M. eumusae were collected during the survey and used to characterize the pathogenic structure of Mycosphaerella spp. using a putative host differential cultivar set consisting of Calcutta-4 (resistant), Valery (intermediate) and Agbagba (highly susceptible). Area under disease progress curve (AUDPC) was higher on all cultivars when inoculated with M. eumusae than with M. fijiensis, but significant (P < 0Æ05) differences between the two species were only observed on Valery. Based on the rank-sum method, 8Æ3% of the isolates were classified as highly aggressive and 46Æ9% were classified as aggressive. About 11Æ5% of all the isolates were classified as least aggressive, and all of these were M. fijiensis. Themajority of M. eumusae isolates (seven out of 11; 64%) were classified as aggressive. A total of nine pathotype clusters were identified using cluster analysis of AUDPC. At least one M. fijiensis isolate was present in all the nine pathotype clusters, while isolates of M. eumusae were present in six of the nine clusters. Isolates in pathotype clusters III and V were the most aggressive, while those in cluster VIII were the least aggressive. Shannon’s index (H) revealed a more diverse Mycosphaerella collection in the DS zone (H = 1Æ81) than in the HF (H = 1Æ50) zone, with M. fijiensis being more diverse than M. eumusae. These results describe the current pathotype structure of Mycosphaerella in Nigeria and provide a useful resource that will facilitate screening of newly developed Musa genotypes for resistance against two important leaf spot diseases of banana and plantain

Gender norms and their implications for banana production and recovery in west Africa

Published online: 22 Nov 2019This study uses the social relations framework to explore gender norms and relations surrounding banana production and banana bunchy top disease (BBTD) containment in six pilot communities in Cameroon and Nigeria. The objective of the study is to understand how gender norms and relations shape and influence access to information and benefit-sharing of productive resources among men and women banana farmers and implications for banana production recovery in the BBTD-affected regions and disease management. Twelve, sex-disaggregated focus group discussions with 120 farmers (78 women and 42 men banana farmers) and 24 key informants were conducted. Data on banana production, access to and decision-making rights over productive resources and social and gender norms influencing adoption were collected. Data were analyzed using a systematic content analysis approach. Results show inequalities stemming from inherent gender and social norms related to access to and decision making over productive resources limiting especially women farmers’ ability to effectively engage in training programs that could lead to adoption of recommendations and technologies. Opportunities to effectively participate in training activities were influenced by gender norms related to household decision making, gender-based labor division and multiple household tasks. Interventions and strategies to contain the spread of BBTD should consider gender-based constraints and opportunities embedded in the communities for optimal results. Social and gender differentiations that impede women should be addressed for inclusive participation. Failure to address harmful norms and gender differentiation in the underlying social structures will benefit one group of people in the community over another

GESTION DES NEMATODES A GALLES PARASITES DE LA CULTURE D\u2019EGUSI PAR L\u2019UTILISATION DE Trichoderma asperellum ET DE LA POUDRE DE GRAINE DE NEEM

The West African watermelon (Egusi melon), Citrullus mucosospermus Fursa, Cucurbitaceae, is one of the vegetable crops subject to high pest and disease pressure, particularly root-knot nematodes. To reduce losses due to these nematodes, a field experiment was conducted at a research station to assess the efficacy of antagonistic fungi and botanical extract on root-knot nematodes parasitising Egusi crop. Two nematode control products, the biocontrol agent Trichoderma asperellum T-12 and neem seed powder, were assessed separately and in combination for their efficacy against root-knot nematodes on the accession Egusi BEN 1-5-13, which is moderately tolerant to root-knot nematodes. The efficacy of the products was compared with that of the chemical nematicide Furadan (nematicide control) and untreated control. Application of Trichoderma asperellum T-12 was at 108 spores plant-1 and neem seed powder at 75 g plant-1, one week before planting. Results indicated a reduction of final root-knot nematode population densities in roots by 89.51% and galling index by 68.86%, compared to those obtained with the control treatment. Application of these products in combination increased the average yields of unhulled and hulled seeds by 100% and 30%, respectively, compared to those of the nematicide control treatment. These results confirm the effectiveness of integrated management strategies to control root-knot nematodes.L\u2019egusi d\u2019Afrique de l\u2019Ouest, Citrullus mucosospermus Fursa, Cucurbitaceae, est l\u2019une des cultures mara\ueech\ue8res sujettes \ue0 une forte pression parasitaire, notamment celle des n\ue9matodes \ue0 galles. Afin de r\ue9duire les pertes dues \ue0 ces n\ue9matodes, un essai a \ue9t\ue9 conduit au champ en station de recherche pour \ue9valuer l\u2019efficacit\ue9 des champignons antagonistes et d\u2019extraits botaniques sur les n\ue9matodes \ue0 galles parasites de la culture d\u2019egusi. Deux produits de lutte contre les n\ue9matodes, l\u2019agent biologique Trichoderma asperellum T-12 et la poudre de graines de neem, ont \ue9t\ue9 \ue9valu\ue9s seuls et en combinaison pour leur efficacit\ue9 contre les n\ue9matodes \ue0 galles sur l\u2019accession \uabEgusi BEN 1-5-13\ubb mod\ue9r\ue9mment tol\ue9rante aux n\ue9matodes \ue0 galles. L\u2019efficacit\ue9 de ces produits a \ue9t\ue9 compar\ue9e \ue0 celle du n\ue9maticide chimique Furadan (t\ue9moin n\ue9maticide) et du t\ue9moin non trait\ue9. L\u2019application de Trichoderma asperellum T-12 a \ue9t\ue9 faite \ue0 108 spores plant-1 et celle de la poudre de graines de neem \ue0 75 g plant-1, une semaine avant le semis de la culture. Les r\ue9sultats ont montr\ue9 une r\ue9duction des densit\ue9s de populations finales des n\ue9matodes \ue0 galles dans les racines de 89,51% et de l\u2019indice des galles de 68,86% par rapport \ue0 ceux obtenus avec le t\ue9moin n\ue9maticide. L\u2019application de ces produits en combinaison a permis d\u2019accro\ueetre les rendements moyens en graines non d\ue9cortiqu\ue9es et en graines d\ue9cortiqu\ue9es respectivement de 100% et 30%, comparativement \ue0 ceux obtenus avec le t\ue9moin n\ue9maticide. Ces r\ue9sultats confirment l\u2019efficacit\ue9 des m\ue9thodes de gestion int\ue9gr\ue9e dans la lutte contre les n\ue9matodes \ue0 galles