Abstract

A study was conducted on the induction of coffee wilt disease (CWD) infection with different types of contaminants using a randomized complete block design with four replications. Coffee seedlings were inoculated with infected bark, sub-bark tissues, wood necrotic and an artificial inoculum. Statistical analysis did not show significant differences (P>0.05) between treatments. Results obtained show that all contaminants used induced main symptoms of CWD. Chronologically, wilting appeared an average 55 DAI, followed by leaf browning (60 DAI), defoliation (69 DAI), leaf drying (82 DAI) and seedlings mortality (86 DAI). The lowest rate of wilting and leaf browning (11.1%) was recorded on seedlings inoculated with infected bark, and the highest rate (33.3%) was observed on seedlings inoculated with wood necrotic. Seedlings inoculated with sub-bark tissue expressed 11.1% of leaf drying, and those inoculated with an artificial inoculum presented 22.2% of mortality. Seedlings inoculated with sub-bark tissue expressed 22.1% of defoliation, while those inoculated with artificial inoculum expressed 39.4% of defoliation. The presence of Fusarium xylarioides was confirmed in dead woods of seedlings inoculated with sub-bark tissue, and those inoculated with artificial inoculum. Results obtained confirm the potential danger of wood debris from infected coffee trees, which can act as a source of infection and promote the spread of CWD when dragged through plantations.

Key words: Coffea canephora, coffee wilt disease, Fusarium xylarioides, field infection, types of contaminants, Democratic Republic of Congo.