With the absence of desiccant diquat, British potato producers are being advised to pay careful attention to field layout, nitrogen management and blight control strategy before planting this spring, according to an article published in Farmers Weekly.
Most independent experts agree a flail-and-spray approach is the next best means of quickly and reliably killing potato haulm after diquat.
It involves a single pass with a flail topper, quickly followed by a single application or sequence of protoporphyrinogen oxidase (PPO)-inhibitor herbicides such as Spotlight Plus or Gozai to kill stems and any remaining green leaf.
Machinery manufacturers have reported a big increase in topper sales in recent months, suggesting that many growers and contractors are gearing up for this mechanical approach.
This is a trend independent potato expert John Keer is seeing across Lincolnshire and East Anglia, with most of his clients investing in their own dedicated machine for 2020.
“It gives you the speed of kill to help manage blight, as it can develop on parts of the canopy that don’t get taken out as quickly by chemicals alone.
“Having your own machine also gives you that extra bit of control over which crops get knocked off and when.”
Farmers Weekly look at some of the implications of switching from diquat to a flail-and-spray approach and how growers can plan ahead to mitigate any problems that might occur.