Abstract

Disease assessment of Persea americana (Avocado) in a local market in Delta State Nigeria showed that only 7% of the fruits were healthy. 36% of the avocado fruits had Cercospora spot; 28% had Diotherella rot and 29% had anthracnose. Plant extracts of three different species; Ocimum gratissimum, Acalypha wilkesiana and Acalypha macrostachya were assessed for inhibitory effect on the radial growth of Cercospora purpurea.  Ethanol extracts of the three plants caused total inhibition of C. purpurea. Crude extract of sterilized and un-sterilized water significantly reduced the radial growth of the fungus. However, the fungistatic effect of O. gratissimum was highest and was followed by A. macrostachya and then A. wilkesiana.

Key words: Plant extracts, inhibition, cercospora spot, antifungal, disease assessment.