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Antagonistic interaction between Epicoccum nigrum and Colletotrichum kahawae, the causal agent of coffee berry disease

Guerra-Guimarães L., Azinheira H.G., Martins A.C., Silva M.C., Gichuru E.K., Varzea V., Bertrand B.. 2007. In : 21st International Conference on Coffee Science, Montpellier (France), 11th - 15th September 2006. Montpellier : ASIC, p. 1284-1290. Colloque Scientifique International sur le Café. 21, 2006-09-11/2006-09-15, Montpellier (France).

Colletotrichum kahawae Bridge and Waller, the causal agent of Coffee Berry Disease (CBD) in Africa, may cause up more than 50% of losses, if no chemical control measures are adopted. The use of antagonists is a potential non-hazardous alternative to control this disease. Several microorganisms (Bacillus macerans, Phoma, Epicoccum nigrum, Aspergillus niger, Penicillium citrinum, Cladosporium sp.) were isolated from phylloplane of arabica coffee leaves and fruits collected in Kenya coffee plantations. E. nigrum was selected for further studies due to its inhibitory effect on C. kahawae growth both in gelose media and in detached green fruits. E. nigrum grown in Roux bottles showed a stationary phase between 21-24 days after incubation, with a maximal dry weight at 31 days. The filtrates of E. nigrum obtained, at different incubation times, caused a slight reduction of C. kahawae mycelium growth and in conidia germination in yitro. The treatment of green coffee berries with E. nigrum filtrates, at the time of inoculation with virulent isolates of C. kahawae suspensions, showed that conidial germination and appressoria formation was also reduced and consequently, the number of lesions was lower and its appearance was delayed around 2 days. Different biological tests showed that the filtrates had no phytotoxicity. The biologically active compounds obtained from filtrates of E. nigrum were extracted with chloroform and separated by thin layer chromatography (TLC). After TLC, two zones showed fungitoxic activity for Cladosporium cucumerinum. For the identification of the inhibitory compounds different testes are currently under study. In the field, treatment of green berries with E. nigrum achieved good control of this disease when compared to levels observed with copper based fungicide.

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