THE EFFECTS OF THE FUNGICIDE BAYFIDAN ON INFECTION STRUCTURE FORMATION BY HEMILEIA-VASTATRIX IN COFFEA-ARABICA CV CATURRA

Treatment of Coffea arabica cv. Caturra seedlings with Bayleton precluded pre-infection structures of the fungus, Hemileria vastatrix, as a target of attack. The fungicide did, however, have an effect on the infection structures within the tissue and fungal disruption occurred between 24 and 48 h post-inoculation (hpi). Extracellular material accumulated on the infection structures. The appearance of the substomatal vesicle and the intercellular hyphae was abnormal, compared to the control, and these structures were swollen. Disruptions in the wall of the infection structures also occurred. Haustorial mother cell collapse was observed 96 hpi, followed by collapse of the entire fungal structure.