Abstract:

Bananas are the most important food crop in Uganda. However, a decline in yields has resulted in
a spatial shift from the traditional banana growing areas of central and eastern Uganda to the south-west.
Plant parasitic nematodes are among the major factors responsible for the decline in yields. In an on-farm trial
to evaluate the use of break-crops to manage nematodes and their impact on smallholder farmer communities
in Uganda, bananas were removed completely from some plots that were planted with either cassava or sweet
potato before bananas were replanted. The cassava break-crop reduced soil populations of Radopholus similis
and Helicotylenchus multicinctus to negligible levels in a period of 15 months. Cassava roots supported
minimal levels of the banana nematodes with the exception of Meloidogyne spp. which increased to levels
higher than those observed in banana. Provision of planting materials of a variety resistant to the African
cassava mosaic virus influenced choice of the break-crop. None of the banana nematodes seemed to multiply
readily on the sweet potato as a break-crop. However, the observations were too few to be conclusive. Soil
nutrient analysis indicated rapid depletion of soil potassium and calcium under the break-crops. In the 3-year
period of participation, farmers’ perception of nematodes as one of the causes of banana decline rose from zero
to 41%. However, the purpose of the trial was still not well understood, with only 32% relating it to pest
management. Participating farmers were introduced to new technologies particularly the use of clean planting
materials generated through tissue culture, improved their knowledge on banana production and consequently,
a change in mindset from considering banana production only for food security, but also as a business venture.