Pineapple (Ananas comosus L.) is one of the most important crops grown in Africa. The fruit is
consumed fresh by many people and hence, source of essential mineral elements, nutrients and
vitamins. This study was conducted to investigate the fungi associated with black rot disease of
pineapple fruits and the effect of the disease on nutritional value of the fruits. The fungi isolated from
black rot pineapple fruits got from Uselu, Ikpoba Hill, Oba, Oluku and New-Benin Markets in Benin City,
were grown on Potato Dextrose Agar (PDA) at room temperature (28±2°C) and observed
morphologically and microscopically for cultural and spore characteristics. Assimilative property of
yeasts was determined with carbon substrates and peptone. Freshly harvested pineapple fruits (six
wounded and six unwounded) were inoculated with the fungus responsible for black rot and incubated
for six days (pathogenicity test). Healthy fruits as well as infected ones were analysed for carbohydrate,
fibre, moisture, protein, and minerals. Two isolates of Ceratocystis paradoxa (black rot fungus), four
isolates of yeasts, Aspergillus niger and Penicillium species were identified. Black rot was prominent in
wounded pineapple fruits after six days of inoculation. The four isolates of yeast assimilated the carbon
substrates and peptone. Furthermore, the infected fruits showed relative decrease in nutrient
composition as compared to healthy fruits. With this basic knowledge of growth of C. paradoxa, the
cause of black rot of pineapple fruit, better handling and storage can be planned in order to reduce crop
losses.