All-out war on the alien invader

摘要

Biological control, the natural alternative to pesticides, may have met its match on the tranquil waters of Lake Victoria. The lake is being choked by water hyacinth, which has clogged lakeshore ports and destroyed a vital fishing industry. Biologists had pinned their hopes on introducing weevils to attack the plants, but over the past two years the insects have made little or no impact on the beautiful weed. Now Uganda's fisheries department wants to blitz the plant with chemicals. A recent pilot study carried out for the government concluded that two herbicides are safe and effective at killing water hyacinth. One also has the advantage of being cheap. It is 2,4-dichlorophenoxyacetic acid, best known for its use a generation ago in the jungles of Vietnam as a compound of the notorious Agent Orange.