Abstract:
The damage caused by Corcyra cephalonic a and Araecenus fasciculatus to cocoa beans
was studied at the Research Department o f Quality Control Division o f COCOBOD,
Tema. The study included breeding o f the two insects on cocoa beans to investigate the
biology, fecundity and progeny production o f the two insect species. The free fatty acid
level o f cocoa beans was also determined and the change in this level due to insect
damage was calculated with respect to undamaged ones. The contaminants produced by
these insects were also determined. Araecerus. fasciculatus did not breed on cocoa beans
but C. cephalonica bred well on cocoa beans. Ten C. cephalonica larvae produced 608
adults after four months storage. C. cephalotiica bred better on crushed cocoa than whole
cocoa beans. Developmental period of 33.8 days was recorded on crushed cocoa beans
while 37.9 days were recorded on whole cocoa beans. Fecundity o f C. cephalonica was
also higher on crushed cocoa beans compared to whole cocoa beans, laying 174 and 141
eggs, respectively.
There was significant difference between the survival and establishment o f C.
cephalonica and A. fasciculatus and hence the damage caused. C. cephalonica produced
the highest quantity o f contaminants o f 77.2 g when alone and 67.8 g when introduced
with A. fasciculatus. The highest percentage seed damage and weight loss of 46.7 and
13.3% were caused by C cephalonica when alone, respectively. The actual percentage
seed damage and weight loss attributable to A. fasciculatus were 0.1 and 0.9%,
respectively.. There was correlation between insect density and damage caused. The free
fatty acid level of cocoa beans was increased by 0.17% and 0.13% when infested by C.
cephalonica and A. fasciculatus, respectively.
