Dicamba, which kills broadleaf weeds but spares grasses,

lasts only a few months in soil, and rarely contaminates water

collaborators at the University of Nebraska in Lincoln isolated a gene from Pseudomonas maltophilia

a bacterium

that is responsible for the breakdown of dicamba. They then transferred this gene into

soya beans, tomatoes and other broad-leaved crops

Monsanto, the makers of the 'Roundup Ready' line of glyphosate-resistant crops

, has already licensed the dicamba technology. The company says it hopes to make dicamba-resistant soyaa beans available commercially in three to seven years, with cotton to follow after that.

Some 90% of soya-bean crops in the United States and 60% of its cotton are genetically engineered to resist glyphosate.

The problem is that glyphosate-resistant weeds are on the ris

And this issue threatens to drive up the cost

resistance won't become a problem with more widespread future use.

But then, that's what they originally said about glyphosate.