The control programme, using a helicopter to spray areas with diquat herbicide, was scheduled to be completed in November and December but was postponed because of unsuitable weather, high water and dirty flow, senior environmental consultant Tim McKenzie said in a report to the Clutha Management committee.
In the report, which will be considered by the committee at its meeting on Friday, Mr McKenzie said control works required relatively clean water and settled weather.
"Due to the high recreational use of the lake during January, control works have been rescheduled for late February/March . . . pending suitable lake and weather conditions," he said.
Lake Dunstan education and enforcement officer Shayne Hitchcock highlighted the effect of the lakeweed on recreational users of the lake in his summer report to the committee.
The use of several areas popular with swimmers and boat users had been somewhat limited because of the concentration of lakeweed, he said.
These areas included Annan Creek and Champagne Gully.
Mr McKenzie said divers had hand-weeded around the Old Cromwell Town beach boat ramps and at Weatherall Creek near the Clyde dam.
Weed that was most susceptible to contact with people and boats was targeted.
"The purpose of this was to reduce the biomass of weed and lower the height of the weed to decrease the risk of transmission within Lake Dunstan and to other lakes within the district," he said.
The Otago Regional Council has defined lagarosiphon as a pest plant.
It was originally sold as an aquarium or ornamental pond plant and is believed to have been accidentally introduced to waterways through disposal into drains and ponds.
The plant spreads quickly and can grow up to 4m in length.
Lagarosiphon is also in Lakes Wanaka and Roxburgh as well as in parts of the Clutha River.
Possible starting dates for the aerial weed control will be advertised next month.
Sites for weed control include Dairy Creek, Weatherall Creek and Burton Creek, Champagne Gully, Jackson's, south of Brewery Creek, Bannockburn inlet, Old Cromwell Town beach, Cromwell jetty, McNulty inlet, Lowburn inlet and boat harbour, Northburn, parts of Pisa Moorings, Bendigo boat ramp, Devil's Creek, Smith's Way and Annan inlet.
