After repeated eradication efforts, Christy Martin now calls the weed Arundo donax the "zombie plant" — a giant reed that has clogged waterways in the southern United States and threatens to do the same to Hawaii streams.

Martin said she was surprised when the U.S. Environmental Protection Agency in July listed Arundo donax as an approved biofuel nationally, allowing it to be planted like corn across the U.S., despite its ability to displace native vegetationand increase flood and fire hazards.

States like California, Texas, and Florida have active control programs against Arundo donax.

Hawaii has been working for years to eradicate it.

The EPA established guidelines to prevent the spread of Arundo donax, but environmentalists are doubtful they will be effective.

"If we can’t control it, I’m not sure guidelines are going to do it," said Martin, a spokeswoman for the Coordinating Group on Alien Pest Species (CGAPS), active in the fight against alien species in Hawaii. "Just when you think you’ve got it under control, there’s a rain and this weed rises from the dead."

As states and federal agencies spend hundreds of millions of dollars annually to battle alien plants, their worst conflicts sometimes involve other federal agencies or departments that effectively support growing them.

Critics raise questions about agricultural rules that allow weeds that have already harmed some areas of the country to continue to be sold in others, and they are raising questions about an unbalanced approach favoring commerce over the environment and looking at an alien plant as a commodity rather than as a potential threat to the environment.

California has spent more than $70 million trying to eradicate Arundo donax.

The U.S. Department of Agriculture, supporting the development of biofuels, has awarded a $99 million loan to Chemtex International for field production of Arundo donax in North Carolina.

Ed Curlett, the spokesman for the Department’s Animal and Plant Health Inspection Service, said supporting the development of biofuels reduces the nation’s dependence on imported oil and fossil fuels.

"Absent action now, our nation’s dependence on foreign oil will grow as our need for more energy grows," Curlett said.

Curlett said the inspection service will be leading an agricultural department team in reviewing Chemtex’s risk mitigation plan for the site.

MANY ALIEN species have been beneficial to agriculture and ranching in the United States, but as conservationists point out, the policies allowing entrance of alien plants is much more liberal than immigration policies toward human beings.

In the past five years in Hawaii alone, about $17.7 million involving 369 contracts and 47,000 acres of land has been spent to fight invasive plant species under agreements with the USDA Natural Resources Conservation Service.

Although President Bill Clinton’s administration established an executive order in 1999 that called for 12 departments and agencies to coordinate efforts to fight invasive plants, the USDA continues to wield the most power.

The secretary of agriculture decides whether to put alien plants on the federal noxious weed list,barring them from entering the United States and restricting their interstate movement. But trade remains at the top of the USDA’s priorities.

State officials have expressed frustration that the USDA gives exemptions to certain plants to improve trade relations with foreign countries. For example, state officials opposed the importation of the orchid phalaenopsis into Hawaii because they feared pests and disease would come with it.

But the USDA overruled objections and allowed them in from Taiwan in 2003. It’s uncertain if the fears proved founded.

Florida biologist Don C. Schmitz said the United States needs to establish a center for biological invasions that can track invasive species, develop strategies for controlling them, and make companies accountable for harming agriculture and the environment.

"The pet industry and ornamental industry have carte blanche," Schmitz said. "They can bring in whatever they want and there’s no cost to them. … It’s a waste of taxpayers’ money. It’s just an endless parade of new invaders. This is not really cost effective for taxpayers."

FIXING THE PROBLEM would require a more effective screening method where the burden of proof that a plant will not prove harmful to the environment lies with the importer — a system put in place in New Zealand in 1993 and in Australia in 1994, critics say.

Entomologist Steven Montgomery said New Zealand, which has operated on a pre-approved list for 20 years, is ahead of the curve.

"We have a lot to learn from them," he said.

There, plants that are not on its list of non-invasive species require a risk assessment study before being put on the list.

New Zealand Land Care Research official Peter Williams said the nursery industry is not happy because the cost of a full risk assessment is expensive, about $30,000, and the applicant requesting the importation does not enjoy any advantage over competitors.

"The agriculturalists don’t like it because it stops them from bringing in new crop plants," Williams said.

New Zealand scientist Paul Champion said the move to a pre-approved list has reduced the government cost of screening plants.

"It has certainly reduced the risk of new pest species from entering New Zealand and allows more of a focus on species we already have in the country," said Champion, the principal scientist for the National Institute of Water and Atmospheric Research.

Australian agricultural officials said the systemhas worked well and comes with considerable economic benefits.

According to the Australia Department of Agriculture, Fisheries and Forestry, since the adoption of the Weed Risk Assessment system in 1994, out of more than 4,300 species assessed, 55 percent have been accepted for importation, 23 percent have been rejected and 22 percent required further evaluation.

Mark Fox, director of external affairs for the Nature Conservancy of Hawaii, said federal officials should be working from an approved list of plants similar to New Zealand and Australia.

"It is really the way to go for the protection of agriculture and wildlife," Fox said.