Biocontrol Efficacy Of A New Strain Of Myrothecium Roridum On Eichhornia Crassipes (Water Hyacinth) In Lagos State Nigeria

ABSTRACT

The use of chemical herbicide in the management of aquatic weeds does not only constitute environmental and health problem but its cost and its non-specific nature calls for the use of biological control agents. An investigation was conducted into the probable use of indigenous fungi as potential mycoherbicides for water hyacinth (Eichhornia crassipes) control. Trips were made to Badagry Creeks, Mile 2 and Lagos Lagoon in Lagos State and Ogun river in Isheri, Ogun state to collect samples of diseased water hyacinth plants. Phytopathogenicity of the organisms from the diseased plant were carried out on both water hyacinth plant and some crops. The best medium, nitrogen source and the optimal pH for the growth of the fungi were also determined. The cellulolytic enzymes activities and phytotoxin production of the fungal isolates were also investigated. Six different fungal species (Aspegillus niger, Aspergillus flavus Penicillium sp., Curvularia pallescens, Fusarium solani and Myrothecium roridum) were isolated from the diseased plant. No disease symptom was observed on the inoculated crops and water hyacinth plant with all the isolates except a strain of Myrothecium roridum Tode which showed a characteristic symptom on E crassipes. Necrosis was observed on the healthy plant 3 days post inoculation with 1x10 spores/ml of Myrothecium roridum. The leaves and the petioles were observed dead at the end of the third week post inoculation. The Disease Incidence (DI) and the Mean Disease Severity (MDS) was 100% and 8.67 0.33 respectively, on day 24 post inoculation.