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.
Key words: Black rot, Ananas comosus fruit, Ceratocystis paradoxa, nutritional value.