Controlling weeds within the arable rotation is vital to produce high yields of good quality crops and to prevent the spread of pests and disease. In recent years, weed management has become an increasing challenge for farmers and their agronomists. The number of new commercial herbicides
and those with novel modes of action has declined significantly since the 1990s. Lack of new modes of action (it is over 25 years since the last herbicide with a new mode of action was introduced), increasing resistance, fewer active ingredients, decreased pesticide availability due to EU
legislation including regulation EC1107/2009, and increasing levels of herbicides in water are all ongoing concerns surrounding weed control. In the absence of new modes of action, the main focus of research over the last 10 years has been on the optimisation of existing herbicides and ensuring
their safe use. Due to the concerns outlined above, farmers are adopting a number of methods of non-chemical control to form more integrated control strategies. Research is now focusing on integrating chemical and cultural control options to tackle weed problems. The three main common areas
currently being investigated are the effects of varying seed rate, drilling date and the potential of varietal competitiveness. The recent introduction of herbicide tolerant oilseed rape (Clearfield varieties, BASF) in the UK has also brought an alternative method of weed control to farmers.
Areas lacking research are the effectiveness of spring cropping and fallowing as a weed control method and also the understanding of the movement of herbicides through soil into water courses.