Effect of pH on mycelial growth and sporulation of Aspergillus parasiticus

Abstract

This study was carried out to evaluate the in vitro use of pH factor in the control of Aspergillus parasiticus which is a notable causative agent of food rot and plant mycotoxins. Under laboratory condition, A. parasiticus was innoculated in Potato Dextrose Broth media of varied pH ranging from 4.0 to 10.0 and incubated for 7 days at room temperature. Within the pH range of 4.0 to 10.0, the mean mycelial dry weight produced ranged from 355.67mg to 302.73mg while the spore production ranged from 4.5 x 107 to 2.8 x 107. There was no significant difference at 95% confidence limit between the mycelial dry weight means except at pH 10.0. The spores formed at pH of 5.0 and 7.0 were significantly different from other pH; with highest number of spores formed at pH of 5.0 and the lowest at pH of 10.0. The lowest mycelial weight and spore formation recorded at pH 10.0 indicate that higher alkaline medium is not suitable for development of A. parasiticus. It was therefore concluded that certain alkaline medium can be used to inhibit the mycelia growth and sporulation of A. parasiticus in order to prevent it from damaging our crops.