CONTRACTORS have started the annual blitz on street weeds -using environmentally friendly herbicides.

But because the weedkiller destroys growth on contact and does not continue working in soil, a second spray will be carried out in September as the growing season comes to an end.

Workmen have been sprinkling roads and pavements using the treatment recommended by government scientists.

While these are less likely to pollute streams and drinking water, they are not as effective at keeping down the weeds.

As a result, Wigan Council highways chiefs are asking people not to bombard them with complaints about visible weeds.

A spokesman said: "There is no sensible alternative if we are to be mindful of public health, but I hope residents will not think we are trying to cut costs or being inefficient."