Burn the land under the feet of the aggressive invaders. . . . Strike at their interests everywhere.

European buckthorn (Rhamnus cathartica) is a particularly aggressive invader in these degraded oak habitats.

Conversely, some species, though commercially valuable in some countries, are regarded as aggressive invaders in other regions.

Just be sure to avoid aggressive invaders like trumpet vine and imported wisterias.

But the researchers say it may be possible to use that factor to gauge whether a recently introduced nonnative plant will become an aggressive invader.

With the evidence of the fish's spawning, hope is fading along the Potomac that the aggressive, toothy Asian invader can be readily stopped.

Mr. Hussein said he was concerned only with ridding Iraq of "the aggressive invaders."

In some areas this plant can form dense stands, becoming an aggressive invader.

Now comes what might be called Son of Kudzu, a nasty and equally aggressive invader from abroad with no apparent redeeming economic or social value.

It is an aggressive invader and, once present, can completely overtake large areas of open land.