ASSESSMENT OF AQUATIC WEED PROBLEMS AND THEIR ECONOMIC SIGNIFICANCE IN GHANA

Weed infiltrations by Pistia, Azolla, Salvinia, and other floating weed types threaten the water quality and physical structure of the Barakese and Weija reservoirs, which provide the main source of drinking water to Accra. Chemical and mechanical methods are recommended in an outlined action program to control weed growth in the reservoirs. 2, 4-D Amine and Dalapon are suggested for use on broadleaved weeds and grasses/sedges, respectively. The use of draglines is also an effective, though expensive, means of removing weed build-ups. Reservoir Officer Maintenance training, preparation, and mobilization are recommended, along with proper weed assessment and management activities. Long-term recommendations include: (1) finding a permanent solution to the high nutrient influx at both Weija and Barakese; (2) conducting studies on specific weed problems at the universities in Legon and Kumasi, and the Institute of Aquatice Biology; (3) initiating a biological weed control program through the Commonwealth Institute of Biological Control Laboratory in Kumasi. A timetable for seasonal weed control is proposed. References and relevant data are included.