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Beware blackgrass complacency

A welcome respite from blackgrass in recently harvested 2017 crops risks setting a false precedent for winter cereals going into the ground this autumn, according to a leading expert.

A welcome respite from blackgrass in recently harvested 2017 crops risks setting a false precedent for winter cereals going into the ground this autumn, according to a leading expert.

“Complacency has been a historical problem in the control of blackgrass, with trends typically following a pattern of good control years followed by particularly bad years,” says independent agronomist Dr Stephen Moss.

“Last season saw good conditions for blackgrass control with pre-emergence herbicide programmes working well, which makes it even more important not to let your guard down during the critical crop establishment period this autumn.

“Not becoming complacent is vital, especially now that there is greater reliance on pre-emergence herbicides which are best applied soon after drilling and before you can see the extent of the blackgrass problem. 

“An appreciable amount of blackgrass seeds can survive for two to three years in the seed bank, so looking back at field history beyond a single season, is vital.”

Dr Moss advises taking a long-term view to blackgrass control. “Considering how much blackgrass was present in summer 2015 and 2016, is as important as considering how much was there last summer.

“By looking back at least two or three seasons, growers are able to gain a real understanding of blackgrass pressure and approach control accordingly.”

With many growers drilling late as part of a blackgrass control strategy, Dr Moss explains that higher soil moisture and cooler conditions, will be beneficial to the efficacy of pre-emergence herbicides, such as flufenacet.

“Therefore, including a pre-emergence herbicide, such as Sunfire or System 50, in a late drilling scenario is vital.

“Keeping up pressure against this damaging weed is even more important this year to ensure that we are building upon last year’s success. Therefore, implementing robust pre-emergence strategies, even when late drilling, should be a priority for growers now,” says Dr Moss.