Scent basil (Ocimum gratissimum L) is a plant of great medicinal, and ornamental value. Parts of the plant, especially, the leaves, are used to garnish food, treat various health challenges ranging from gasrtro-intestinal problem, cough etc. Despite its usefulness, the leaves are affected by some yellowish-brown distortions which affect their maximum use as ornamental and others. This work is aimed at isolation and identification of the fungus associated with this foliar problem, and its effect on the proximate and phytochemical composition of the leaves which could reduce their maximum benefits to man. Standard method was used for the isolation of the fungal culprit, and the manual of Barnett and Hunter was used for its identification. The method of AOAC was used for the analysis of the proximate and the anti-nutrient compositions, while the mineral composition was determined using atomic absorption spectrophotometer. All the chemicals used in this work were of analytical grades. The result showed that Geotrichum gloeosporoides was associated with the leaves of the plant. Moisture, carbohydrate, crude fat, protein, crude fiber and ash, all the minerals sodium, potassium, calcium, magnesium, phosphorus and iron, and the anti-nutrient alkaloids, phenol, glycoside, tannins, steroids, flavonoids, and quinone contents of the apparently healthy leaves, were significantly higher than the infected (p <0.05). Generally, the results showed that the organism caused significant decrease in the proximate and phytochemical contents of the infected leaves, which implies a marked reduction in the nutrients benefits consumers could derive from the leaves of the plant.
