Developing "designer" systems for crop production that combine chemical resistance in the crops plants with applications of the chemical to kill weeds or pests of the crop. For example, genetic engineering has produced herbicide-tolerant crops on which are a applied general systemic herbicide to kills all weeds.
There are differing views as to whether there would be environmental advantages or disadvantages in using a single, broad-spectrum herbicide compared with the current practice of using several different products. Some people have suggested that the level of herbicide usage on herbicide tolerant crops will rise, while others have suggested it will fall.
The UK plant breeding industry has agreed with the UK government for a programme of managed development of herbicide tolerant genetically modified (GM) crops whereby the first farm-scale plantings are strictly limited and monitored for ecological effects along with comparable plantings of conventional crops. This process will be underpinned by the strict guidelines for best practice in using GM crops. The results of these farm-scale evaluations will be carefully assessed before moving further. If, during this process, evidence of harm is found then the UK government will take appropriate action. The industry has also made the important commitment that no insect resistant GM crops will be introduced into the UK for the next three years. The concept of managed development provides a precautionary way forward to investigate in a proper scientific framework the concerns that some GM crops might be harmful to the environment.
Widespread planting of GM herbicide tolerant crops may lead to changes in agricultural practice that will further reduce biodiversity. Herbicides applied to such GM modified crops should be assessed for their effect on non-target species. It is extremely important that commercialisation of GM crops does not proceed before this information is available and has been assessed.