FIELD TRIAL ON EFFICACY OF Trichodernma harzianum and Rhizopus stolonifer ON THE CONTROL OF COCOA BLACK POD DISEASE PATHOGEN (Phytophthora palmivora)

Abstract

This study investigated the efficacy of Trichoderma harzianum and Rhizopus stolonifer as biological control agents of Phytophthora palmivora in experimental plots set up in three cocoa farms where the pathogen pressure was found to be very high. The field trial was carried out during the year 2010and 2011 growing seasons at Aba - ljesa 45Km from Ile -lfe Osun State Nigeria. The efficacy of the two fungal isolates was compared to fungicide (Metalaxyl-m and cuprous oxide) while water was used as control. Disease incidence was recorded for each tree in each plot every other week after the first application till the end of experimentation. All data obtained were subjected to analysis of variance. The effects of the test antagonists on pod infection differed significantly at 5%. The total mean number of pods produced by trees treated With Trichoderma harzianum and chemical were not significantly different (P < 0.05).The percentage infection of pods by the pathogen was very low and found not to be significantly different (P< 0.05) in plots treated with chemical and Trichoderma harzianum In all the treatments, the total mean numbers of pods produced were not significantly different (P < 0.05) except control where the percentage infection rose steadily till the end of the experiment. These results raised the hope that if the two biocontrol agents are effectively applied, the establishment of the pathogen on the pod would be prevented, thus encouraging flower production and invariably improve the yield.