Screening three Aspergillus species for antagonistic activities against the cocoa black pod organism (Phytophthora palmivora)

Abstract

In vitro screening using the dual culture technique was undertaken to assess the potential of three Aspergillus species, A. fumigatus, A. repens and A. niger as biological control agents against Phytophthora palmivora, the pathogen of cocoa black pod disease. The test organisms were isolated from the same cocoa farm where the disease occurred. Results revealed that all the test antagonists effectively checked the growth of the pathogen. The test antagonists grew faster than the pathogen and produced inhibition zones thereby limiting the growth of the pathogen. In solid medium, A. repens was the most antagonistic organism under the conditions of this study. The culture filtrates of the test fungi also inhibited the growth of P. palmivora with A. niger showing the highest percentage inhibition (54%) and A. repens the least (44.5%).