It's a while since we've seen any news stories about eco-warriors. Not long ago, they were a regular feature, rolling around, squashing GM¹ test crops, in their white, Tyvek coveralls. Why were they making all that fuss? And has the problem disappeared?

Stories about GM crop testing seem to have dried up too. Try Googling for new stories and you won't find much of a collection. So have the protests stopped because the testing has stopped? If you want to find out, you have to dig deep.

The GM companies assured us that they only wanted to feed the world and reduce the need for the most toxic weed-killers. They weren't trying to poison anyone with dangerous, transgenic veggies. To hear some people talk - loudly trumpeting the supposed benefits and keeping very quiet about any problems and uncertainties - you'd think the chemical companies and genetic engineers were on a saintly mission. Advocates of the technology thought protestors were barmy, modern-day Ludites, trying to stop progress. But there was more to it than simple mistrust of scientists, tampering with our fodder.

Food safety, about which there was plenty of opinion but very little data, was only one issue. 'The Greens' were also concerned that the possibility of environmental damage was being lightly dismissed. The tests were, themselves, likely to cause damage to the environment, that would be irreversible. Those carrying out the tests had certain expectations about how far the wind and flying insects would be able to carry pollen. Their estimates were far from accurate.

The situation in Canada provides a fine illustration of what can happen when the authorities take a relaxed attitude. Canada now has oilseed rape plants behaving worse than any noxious weed. And it only took three years from the first planting of GMHT² rape, to get a rape superweed. The trick was 'gene stacking' by 'volunteer' oilseed weeds³.

'Volunteers' are the plants that weren't deliberately sown, but were accidentally dropped. The seeds may have been dropped by an earlier crop or spilt from farm machinery or lorries. 'Gene stacking' is what happens when various genetically modified crops cross-pollinate. In the case of Canadian GM rape, volunteers from three differently modified crops stacked genes for tolerance to three different weed-killers. Clearfield, Liberty and Roundup Ready oilseed plants were very promiscuous cross-pollinators. Now it takes something far more toxic than Clearfield, Liberty or Roundup to eliminate the superweeds.

That's not the end of the problem with superweeds. Oilseed rape is a member of the cabbage family⁴ and it will happily cross-pollinate with some of them too. There are hundreds of members of this family and so far, rape has been found to hybridise with several, including mustard, wild turnips, wild radish and wild cabbage. It doesn't require very much time or many such successful matings to produce a super abundance of superweeds. Instead of sloshing one application of relatively environmentally benign herbicide over a field of rape, the farmer must resort to more damaging chemical control - and possibly several applications.

In order to eliminate this problem, spraying also has to be carried out around the margins of the fields, where the already threatened wildlife is further imperilled. The plants we regard as weeds are food to many invertebrates which, in turn, are food for birds and small mammals. In a time when these areas have been recognised as an important habitat and refuge for endangered wildlife, it seems ironic that a technology that was, apparently, going to help protect them, could instead make it necessary to sterilise them of life, in an effort to eliminate the super herbicide tolerant GM weeds.

So, it might be supposed that GM crops and eco-warriors have disappeared from our news because it has been generally accepted that genetically modified herbicide-tolerant crops, that share their genetic advantages with each other and the surrounding weeds, are a rotten idea and should be forgotten. But they're still at it, rehabilitating old herbicides and making new GM seeds. Remember the Vietnam war and how they drenched the jungle with powerful herbicides in an effort to turn the jungle into a barren waste, where no army (or anything else) could be hidden? They used Agent Orange and Dicamba - neither of which are environmentally friendly - as their jungle-killer. Now there are Dicamba GMHT seeds to replace the old Clearfield, Liberty and Roundup GMHT seeds.

Well, it's an expensive business. You can't expect them just to give it up as a bad job because there are a few insurmountable problems to overlook. No problems have been reported, according to the GM lobby. There's nothing at all to worry about really. No, really?