East African highland banana production as influenced by nematodes and crop management in Uganda

Production loss caused by nematodes in East African highland banana was eva luated at Sendusu, near Kampala in Uganda, 1120 m above sea level. The comm only grown cultivar, Mbwazirume, was grown in nematode-infested and non-inf ested plots under heavily mulched, clean-weeded and millet-intercropped man agement regimes. Influence of the different treatments was evaluated over t he second to the fourth crop cycle and management was observed to have the greatest influence on production. The non-infested heavily mulched plots pr oduced 16.1 tonnes per ha per cycle compared with the clean-weeded and non- infested millet-intercropped plots only 5.6 and 5.3 tonnes per ha per cycle , respectively. Presence of Radopholus similis and Helicotylenchus multicin ctus reduced the average production in the well mulched, clean-weeded and m illet-intercropped plots by 30%, 32% and 38%, respectively. The nematode-in duced loss is a result of a reduction of bunch weight, a reduction of flowe r production and an increase in plant toppling. When plant toppling occurre d on a mat, the chance was highly reduced that this mat produces a harvesta ble bunch in the following cycle. Damage by the banana weevil, Cosmopolites sordidus, was higher in nematode-infested plants compared with noninfested plants. It may be that in nematode-infested plants, weevil larvae are more successful in developing or that adult weevils prefer nematode-infested pl ants for egg disposal. No interaction between Black Sigatoka and nematode i nfestation was observed.