Effectiveness of learning and experimentation approaches for farmers as a community based strategy for banana xanthomonas wilt management

Banana Xanthomonas wilt (BXW) is a devastating disease for banana and enset in east, central and Horn of Africa since 1968. The disease has spread to all banana growing countries in the region in the last decade, causing yield losses of up to 80 to 100%. Several efforts have been undertaken to develop and implement technologies for BXW management and their effective deployment with varying successes. This paper presents a new participatory approach for managing BXW named Learning and Experimentation Approaches For Farmers (LEAFF) and describes how it was implemented, tested and evaluated among 220 farmers across two agroecological regions, central and South-western Uganda. Results showed that there was a general reduction in the number of infected plants, corresponding to 7% increase in productivity of banana among the LEAFF compared to the non LEAFF participating farmers. The findings suggested that scaling out LEAFF to different parts in the region can significantly contribute to effective and sustainable adoption of BXW management technologies, and in turn, can lead to improved productivity and smallholder farmers’ livelihoods

In-vitro proliferation of Musa balbisiana improves with increased vitamin concentration and dark culturing

Musa balbisiana is a wild banana genotype with important traits such as drought tolerance and disease resistance. Uniform and clean plants are often required to study these traits in different laboratories but plants can only be generated through a tissue culture process yet for a long time a protocol for regeneration of the same has not been available. Here, we demonstrate that modification of the anti-oxidant content of the in- vitro plant proliferation medium through adjusting the concentration of ascorbic acid and thiamine HCl in the basal MS medium together with subjecting the explants to dark culturing conditions improved proliferation of M. balbsiana by over 10 fold. These treatments resulted in 40 shoots per initial explant material at the best performance

Susceptibility of common weeds and cultivated crops in major maize growing agroecological zones of Uganda to viruses causing maize lethal necrosis disease

Maize lethal necrosis (MLN) disease is caused when maize plants become co-infected with Maize chlorotic mottle virus (MCMV) and potyviruses notably Sugarcane Mosaic Virus (SCMV). Apart from maize, little is known about susceptibility of weed species and cultivated crop species usually growing in proximity with maize to MLN viruses in Uganda. The common weeds and crop plants were mechanically inoculated with combined sap from MCMV and SCMV infected maize plants. Samples were tested for MLN causing viruses by Double Antibody Sandwich Enzyme-Linked Immunosorbent Assay (DAS-ELISA) and Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). The weeds that were susceptible to MCMV were Digitaria abyssinica, Eleusine africana and Roetboellia cochinchinensis; while those susceptible to SCMV were Pennisetum purpureum, Panicum maximum and Roetboellia cochinchinensis. The cultivated crops were susceptible only to MCMV and included cassava (Manihot esculenta), groundnut (Arachis hypogaea) and bean (Phaseolus vulgaris). Common weeds and cultivated crops growing close to maize in Uganda have differential susceptibility to MLN causing viruses and can act as reservoirs of MLN causing viruses. It is critical to identify non-MLN hosts in cultivated crops for crop rotation and early weeding to reduce on MLN virus inoculum in cropping syste

Potential of Infected Banana Parts to Transmit Xanthomonas campestris pv. musacearum

The potential of different parts of banana bacterial wilt infected banana plants to transmit the wilt bacterium, Xanthomonas campestris pv. musacearum (Xcm) was investigated. Banana parts (fresh leaves, dry leaves, fresh pseudostem sheath, fruit peelings and corms) picked form diseased plants were used to inoculate the test plantlets. Prior to inoculation, banana wilt bacterium was isolated from these parts, quantified and confirmed through pathogenicity tests on healthy banana potted plantlets. Inoculation with banana parts was then done by placing infected parts into contact with wounded healthy banana pantlets. Fresh plant parts contained more bacterial cells than dry leaves. This isolated bacteria induced disease symptoms often associated with Xanthomonas campestris pv musacearum infection. Inoculation results showed that some parts (mainly the fresh banana parts) were able to cause infection to healthy potted banana plantlets only after wounding the test plant roots. Even then, the disease incidence was low (5-20%). Therefore, practices and activities that involve movement of fresh banana parts some of which could be from infected banana plants should be discouraged as it has been shown that these parts can carry viable and pathogenic bacteria

Xanthomonas campestris pv musacearum Host Range in Uganda

The bacterium, Xanthomonas campestris pv musacearum causes the banana bacterial wilt. Effective disease management requires removal of inflorescence and cultural practices such as sterilization of garden tools and rouging of infected plants and destruction of diseased plants. It also requires good knowledge of host range of this pathogen. Symptoms include premature fruit ripening and yellowing of leaves. The goal of this study was to investigate etiology of the disease in banana, which up to now is not well studied to guide screening processes. Thus, bacterium was isolated and 1 mL containing 1x10 8 bacterial cells/mL was injected into petioles of youngest open leaves/3rd internodes from shoot tips and 25 plants each, of the 20 suspected plant species assembled in pots in a farmer's field. This isolated bacterium induced symptoms often associated with X. campestris pv musacearum infection to banana plantlets within 2-5 weeks. The bacterium also incited wilt symptoms in wild bananas relatives, Musa zebrine and M. ornate and in an ornamental / wild weed Canna indica but not in other test plants. In the banana plantlets the earliest observable external symptom was collapse was collapse of the leaf blade along the midrib followed by scalding and dull green appearance of the leaves

Potential of infected banana parts to transmit Xanthomonas campestris pv. musacearum

No Abstract. African Crop Science Jouranl Vol. 14 (2) 2006: pp.137-14

Xanthomonas campestris pv musacearum host range in Uganda

No Abstract. African Crop Science Jouranl Vol. 14 (2) 2006: pp.111-12

Reaction of Banana Germplasm to Inoculation with Xanthomonas campestris pv. musacearum

Pot trial to evaluate the reaction of Uganda's local banana germplasm to artificial inoculation with Xanthomonas campestris pv. musacearum (Xcm) was established in 2004 and 2005 in Mukono district, Uganda. X. campestris pv musacearum causes infection causes premature fruit ripening and leaf wilting, killing every affected plant hence leading to total yield loss. The disease is managed through cultural practices but it was thought that use of resistant varieties would provide a better management option. Potted plants in a farmer's field were therefore inoculated with a bacterial suspension containing 1x108 bacterial cells/mL of Xcm. 1mL of bacterial suspension was injected into the petiole of the youngest open leaf using a hypodermic needle. Twenty five plants of each of the 42 banana genotypes were involved in the study. Wilt disease developed in the three months old banana plantlets of all local germplasm tested except for Musa balbsiana

Reaction of banana germplasm to inoculation with Xanthomonas campestris pv musacearum

No Abstract