The potential of using botanical insecticides for the control of the banana weevil, Cosmopolites sordidus(Coleoptera: Curculionidae)

Crude extracts of chinaberry tree (Melia azedarach L.), mexican marigold (Tagates spp.), water hyacinth (Eichornia crassipes, Martius) and Castor oil (Ricinus communis L.) were tested for their effect onweevil mortality, settling responses and oviposition in the laboratory. All extracts of the botanicals did not show significant effects on weevil mortality compared to controls. Weevil settling responses oncorms treated with extracts of botanicals compared to controls were statistically similar after 1 h and 72 h of observation. Oviposition was significantly low on corms treated with M. azedarach, Tagetes sppand R. communis compared to controls. Oviposition on corms treated with water hyacinth extracts was not statistically different from oviposition on controls. The data indicates that botanicals possess limited insecticidal properties but the potential of M. azedarach, Tagetes spp and R. communis to control the weevil through preventing oviposition needs further investigation

Farmers’ awareness and perceived benefits of agro-ecological intensification practices in banana systems in Uganda

Declining soil fertility and pests and diseases are major constraints to banana productivity in smallholder farming systems in Uganda. This study explored farmers’ awareness and perceptions on agro-ecological  intensification (AEI) practices for addressing these constraints in five banana-growing districts in Uganda. Stratified random sampling procedure was used to select 60 households for a survey from different agro-ecological zones and banana production systems. The household survey was complemented with focus group discussions to obtain qualitative data on farmer perceptions on benefits and constraints to AEI application on-farm. Thematic content analysis and descriptive statistics were used to analyze data. Results of the study show that most of the interviewed farmers were aware of the AEI practices although not all those aware had adopted the practices. Farmers were motivated to apply AEI practices perceived to offer multiple benefits: pest and disease management, enhanced productivity, soil fertility improvement and ecological adaptability. Major constraints to application of AEI practices by farmers include insufficient knowledge, labour intensiveness and limited access to markets. A transition towards intensification of smallholder banana systems requires that the full range of ecosystem services provided by AEI practices are recognized and valued by farmers. Therefore, empowering farmers with knowledge on their agro-ecological systems and locally adapting AEI practices is essential for realization of benefits and wider adoption of AEI practices.Keywords: Agro-ecological intensification (AEI), awareness, banana, perceived benefits, smallholder, UgandaAfrican Journal of Biotechnology Vol. 12(29), pp. 4603-461

Farmers' awareness and application of banana Xanthomonas wilt control options: The case of Uganda and Kenya

Banana is a key staple and cash crop in east and central Africa. However, the recent outbreak of Banana Xanthomonas wilt (BXW) has threatened farmers whose livelihoods depend on the crop. Since 2002, stakeholders embarked on campaigns to sensitize farmers on the disease and its management. This study evaluated the effectiveness of these efforts by examining farmers' awareness of the disease, control options and their application in Uganda and Kenya. Data on BXW distribution and incidence, farmers' awareness of symptoms, mechanisms of spread and control options of the disease and banana production were collected through household surveys conducted in 2010. The results indicated that most farmers (> 90%) were aware of the disease and its symptoms and more than 50% were aware of the recommended control measures. Farmers obtained information on the disease from multiple sources but farmer-to-farmer interaction was the main source suggesting the key role rural social networks play in managing the disease. Not all affected farmers were able to apply control measures due to cost of intervention, lack of labour and inputs. The study recommends strengthening of linkages among stakeholders for better coordination of efforts and participatory development and promotion of farmer-oriented interventions that address farmer constraints

Banana Xanthomonas Wilt infection: the role of debudding and roguing as control options within a mixed cultivar plantation

An optimal control framework is designed in which the use of clean planting materials, debudding, disinfection of tools, and roguing are considered as control measures of Banana Xanthomonas Wilt (BXW) within a plantation of multiple cultivars. A model for a special case of two cultivars (AAA- and ABB-genome cultivars) was analyzed. By Pontryagin’s Maximum Principle, we characterized and discussed possible control strategies that substantially reduce the infection levels of BXW within a plantation of ABB- and AAA-genome cultivars. A combination of both prevention and containment controls yielded the greatest decline in the infection levels in both cultivars. Additionally, for effective BXW management, it is important to assess the endemic level of the plantation before application of controls, and once implemented, this should be maintained even when the disease is undetectable to eliminate possible resurgence

Olfactory responses of banana weevil predators to volatiles from banana pseudostem tissue and synthetic pheromone

As a response to attack by herbivores, plants can emit a variety of volatile substances that attract natural enemies of these insect pests. Predators of the banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) such as Dactylosternum abdominale (Coleoptera: Hydrophilidae) and Pheidole megacephala (Hymenoptera: Formicidae), are normally found in association with weevil-infested rotten pseudostems and harvested stumps. We investigated whether these predators are attracted to such environments in response to volatiles produced by the host plant, by the weevil, or by the weevil¿plant complex. We evaluated predator responses towards volatiles from banana pseudostem tissue (synomones) and the synthetic banana weevil aggregation pheromone Cosmolure+ in a two-choice olfactometer. The beetle D. abdominale was attracted to fermenting banana pseudostem tissue and Cosmolure+, whereas the ant P. megacephala was attracted only to fermented pseudostem tissue. Both predators were attracted to banana pseudostem tissue that had been damaged by weevil larvae irrespective of weevil presence. Adding pheromone did not enhance predator response to volatiles from pseudostem tissue fed on by weevils. The numbers of both predators recovered with pseudostem traps in the field from banana mats with a pheromone trap were similar to those in pseudostem traps at different distance ranges from the pheromone. Our study shows that the generalist predators D. abdominale and P. megacephala use volatiles from fermented banana pseudostem tissue as the major chemical cue when searching for pre