Abstract:

Musa (banana and plantain) provides a major source of carbohydrates for about 400 million people of
whom 20 million are from East Africa. Yet, banana is threatened by number constraints, banana streak
virus inclusive. Banana streak virus (BSV) was monitored in Rakai and Ntungamo, Uganda for up to 72
months after planting (MAP) and 29MAP respectively. BSV incidence increase over time was fitted into
exponential model and spatial spread analysed by 2DCLASS and 2DCORR. BSV infection was initiated
in Rakai 29 months after planting (MAP), but only 6 MAP in Ntungamo. BSV incidence then increased at
a rate of 0.10 plants respectively / infected plant / month at a rate 0.23 plants / infected plant / month in
Rakai and Ntungamo respectively. In both sites, spatial analysis showed that there were significant
aggregated BSV spatial patterns. New infections were more likely to occur within a 10 rows/coloumns
from an old infection. Significant edge effects were also detected in Ntungamo, indicating that there
was significant spread from the immediate surroundings (infected established field suggesting need for
separation of new fields from old infected fields to delay onset of BSV. Roguing should be frequent
enough to offset rate of BSV incidence increase. The study shows that BSV is a slow spreading
disease; however, there is sufficient time in this perennial cropping system for it to increase to
epidemic levels. It is however, possible to check the advance of the BSV epidemic through
phytosanitary measures.