Purpose: Banana Bunchy Top Disease (BBTD) was first reported in Malawi in 1997. The major strategy used to deal with BBTD required banana growers to uproot and burn all their bananas and replace them with disease-free imported planting materials. This had limited success only. This paper uses an actor-oriented approach to explain this experience by assessing the different knowledge types and dynamics. Design/methodology/approach: Using a qualitative study design we sampled respondents through snowball and purposive sampling. Focus group discussions and key informant interviews were used to interview 120 farmers in 5 villages, 5 extension experts, 6 crop scientists, 2 banana research scientists and 3 NGOs leaders. Transcripts were analysed using Grounded Theory Methodology. Findings: The results showed that development agents and farmers conceived of, and dealt with, BBTD on the basis of different types of knowledge and dynamics. The battle that arose around this knowledge interface explains why the top-down approach to dealing with BBTD led to resistance from banana growers. These top-down approaches contrast with the widely-used rhetoric of using bottom-up approaches to foster co-innovation. Practical implications: Development actors need to embrace co-innovation principles and move away from merely sticking to the label of bottom up approaches. Theoretical implications: Using participation as a means to achieve predetermined strategies lead to failure and conflict in development programmes while as consulting with, and listening to farmers has potential to increase their cooperation in development programmes. Originality/value: The study informs that while there is so much talk about a shift in extension approaches, not much has changed to embrace co-innovation amongst actors.