Cultural control methods cannot fully compensate for the loss
of cereal grass weed herbicides, weed scientists said at the 46th
British Crop Production
Council annual weed review in Peterborough.
But there were methods that could support the performance of the
products that were still available, they suggested.
A number of key products are likely to be removed as new EU
legislation works through in the coming years, while very few new
products are being developed.
In a review of research from the past 40 years Peter Lutman and
Stephen Moss of Rothamsted
Research showed, in general, cultural control was less
effective, more variable and more expensive that using
herbicides.
The most effective agronomic practices could only achieve 70 to
80% control of blackgrass, for example, while the best herbicides
could give over 90%.
However, appropriate cultural controls could take the pressure
off herbicides, said Dr Lutman. "The current techniques of
non-inversion tillage, early planting, low crop seed rates and
continuous winter cropping, all put huge pressure on herbicides.
This approach will not succeed in the future when fewer products
are available and if grass weed resistance becomes more of a
problem."
Major adjustments would be needed to farming practices,
including rotational ploughing and spring crops in the rotation, he
said. "If we do not change the way we grow our crops, we run the
risk that they will be overwhelmed by unmanageable grass weeds in
the future."
