Black-grass and Brome are the most difficult to control grassweed problems in winter oilseed rape, according to a recent farmer survey conducted on behalf of BASF.
In the survey, over 52% of oilseed rape farmers considered resistant Black-grass to be one of the main grassweed problem on their farm and it was by far the most difficult weed to control. Sensitive or non-resistant Black-grass was said to be a major weed problem on 60% of farms, with 52% of farms stating that Brome was the top weed they had to tackle. Asked about their overall weed strategy, nearly 60% of growers thought that controlling grassweeds in rape helped ease the problem in the following wheat crop, but they tended to allocate their weed control costs to the rape crop alone rather than across the farm.
“With Black-grass, a whole farm, long term control strategy using all available crop management tools is the only way to get on top of this damaging weed. Good grassweed control at an early stage protects this year’s rape crop and reducing the weed seed bank in next year’s crop,” reminds Diane Heath, BASF Oilseed Rape Product Manager.
The survey also indicated that Cereal volunteers were found on 87% of all farms growing winter oilseed rape, but they were considered to be the easiest weeds to control along with Wild-oats and Rye-grass.
“Black-grass dormancy levels this year are thought to be low and with the recent levels of soil moisture we should see a good flush of Black-grass and volunteers in oilseed rape. If growers are looking for top level control of Black-grass and volunteers together, then Aramo, based on the active ingredient tepraloxydim, is the graminicide of choice. Being a “dim” herbicide, it controls Black-grass including those difficult populations with enhanced metabolism resistance, as well as Annual Meadow-grass, Wild-oats, Sterile Brome and Perennial Rye-grass. It is particularly strong on Annual Meadow-grass which was said to be a problem on 70% of farms.”
“Damage to yield through grassweed competition takes place in the first few weeks after crop emergence, so it is important to apply Aramo at 1 l/ha, using a fine spray for good coverage. when the Black-grass has 2-3 leaves. It will also be important to keep an eye on early-drilled fields, as the control of larger grassweeds tends to be more variable. It should be applied before the end of November or 9 true leaves of the crop, which ever occurs first,” warns Diane.
