WASHINGTON -- It's not out of the testing phase yet, but a genetically-modified grass developed by biotech giant monsanto co. is already making waves.

the st. louis, missouri-based producer of gmo corn and soybeans has used gene technology to engineer a type of turf grass that would be resistant to its roundup herbicide or weedkiller.

the turf grass -- called creeping bentgrass -- is commonly used on golf courses because it has fine leaves that tolerate mowing.

scotts company, a marysville, ohio-based manufacturer of lawn products, which is working with monsanto, has sought permission from the us department of agriculture (usda) to market the genetically-modified bentgrass to golf courses.

but on thursday, the international center for technology assessment (cta), a washington-dc based pressure group, announced it had filed a petition asking the usda to block the release of the gmo grass, arguing it could contaminate related domesticated and wild grasses growing nearby.

"what monsanto and scotts are doing to creeping bentgrass will make it a more threatening invasive species for those who don't want it in their lawn or park," cta attorney peter jenkins said in the petition. "their proposal amounts to genetic assault and battery, recklessness and tresspassing."

cta is also concerned using more herbicide will create a resistant class of "superweeds".

scotts company, however, maintains that the experimental grass would make an environmentally-friendly alternative to the strains of grass now used on golf courses.

although the engineered bentgrass still needs years of testing, it's an "everybody wins" scenario because the grass will be environmentally friendly, said tim portland, a scotts company spokesman. "bentgrass is not a noxious weed," he said.

monsanto company declined to comment.