rosali smith of the center for biological control sees to it herself that the animals reach their destinationnser the water hyacinths grow, the better it is for their little enemy. they can multiply here quickly. >> our approach with releasing the planthoppers is using them as a green herbicide so as many released as possible, early in the summer, which allows the population to build up quickly. that allows them to damage the plants as soon as possible so they can't expand over the dam. reporter: water hyacinths form dense mats that drift across the lake. when they collide, their underwater roots become entangled, and block out any light. gradually, a huge dense carpet of plants forms. they can completely overgrow bay areas, which is not only an ecological problem, but an economic one too. many people at the dam live from tourism. each year, columns of workers remove the plants from the water with long rakes. it's a slow and laborious process that also only works on smaller waters. in huge areas like this though, the tiny helpers have to step in. the traces of their work can be seen on the wa

they're on their way to the hot to be sport dam. rosalie smith, of the center for biological control, sees to it herself that the insects reached their destination. the denser the water hyacinth scro, the better it is for their little enemy. they can multiply here quickly. o approach with releasing the plan top is is using them as a green herbicide, sir, as many as releases as possible early in the summer. and that allows their populations to build a quickie. and that will say just allows them to damage the. * ponds as soon as possible, so that the plans try and expand their growth over the damn water high is since form dense mats that drift across the lake. when they collide, their underwater routes become entangled and block out any light. gradually, a huge dense carpet of plans forms. they can completely over gro bay areas, which is not only an ecological problem, but in economic one too many people at the damn live from tourism. each year columns of workers removed the plants from the water with long rakes. it's a slow and laborious process that only works on smaller waters in hug

together with a leaf of their favorite food, they're on their way to the hot to be sport dam. rosalie's smith of this center for biological control sees to it herself that the insects reached their destination. the denser the water hyacinth scro, the better it is for their little enemy they can multiply here quickly. o approach with releasing the plans up is is using them as a green herbicide, sir as many as releases as possible early in the summer. and that allows their populations to build a quickie and that also just allows them to damage the. * ponds as soon as possible, so that the plans try and expand their growth over the damn water high is since form dense mats that drift across the lake. when they collide, their underwater routes become entangled and block out any light. gradually, a huge dense carpet of plans forms. they can completely over gro bay areas, which is not only an ecological problem, but an economic one too many people at the damn live from tourism. each year columns of workers remove the plants from the water with long rakes. it's a slow and laborious process that only