Abstract

Water hyacinth (Eichhornia crassipes) is a noxious aquatic weed in Nigeria and many parts of the world. A potential mycoherbicidal agent for the control has been identified recently as Myrothecium roridum Tode. The best media for in-vitropropagation was investigated using seven culture media; potato dextrose agar (PDA), malt extract agar (MEA), potato sucrose agar (PSA), sabouraud agar (SA), potato carrot agar (PCA), Czapek-Dox agar (ZA) and a semi artificial diet, which included the material from the fungal host’s plant (WHA). The effect of nitrogen sources (ammonium chloride, sodium nitrate, ammonium nitrate, sodium glutamate and glutamine) and pH on the growth of the fungus was also determined. The mycelia growth was assessed by diameter measurement on agar plates and the conidial yield was measured with a Neubauer hemocytometer slide. The mycelia growth was maximum on PSA and minimum on ZA. The conidial yield was highest on MEA. The mycelia growth and spore concentration of the fungus were highest on sodium glutamate and glutamine respectively, when used as nitrogen sources. The optimal growth pH was 5.5.

Key words: Media, Mycoherbicide, Myrothecium roridum Tode, nitrogen sources.