While the cold weather that descended on the UK this week may hamper growers plans to apply tank-mixes, applications of Liberator (flufenacet and diflufenican) can still go ahead where conditions are suitable for spraying, says independent agronomist Sean Sparling.
Liberators recent label extension could be of great value to growers who were unable to make applications of residual herbicides last autumn, for its effects should work on into April and the stronger growth that will come with warmer temperatures, says Sean.
Liberator is the only available form of flufenacet left for grass weed control of winter wheat this spring,” Sean points out. It can be applied up until 31st March at a rate of at 0.3L/ha. And while there is currently no point in applying a contact herbicide yet as these need the metabolism of the plant to be active, residuals will sit on the soil surface, and when the weather does turn, it will target the roots and shoots of germinating black-grass.”
Past experience has shown that spring germinating black-grass will still come up in April. Growers who apply Liberator on its own now, or in a tank-mix with a contact herbicide such as Atlantis WG (mesosulfuron + iodosulfuron) later in the month when the weather is warmer, will benefit from the residual effects that will work on into April, when growth will be much stronger,” he adds.
Sean notes that where pre-ems were sprayed in the autumn the control has been remarkable. However, many autumn-sown wheat crops are yet to receive a residual and with so many jobs on the to-do list, growers may be starting to worry about getting on the land.
However, if they are planning to control black-grass in a single pass with Atlantis WG or with a tank-mix including any contact herbicide, they need to wait, he advises.
Plants need to be actively growing for any contact herbicide to be taken up. We are coming to a point where weve one last chance to control black-grass and there is absolutely no point in risking sub-optimal control by applying it in adverse conditions.”