For most UK potato growers and their advisers, including Monmouthshire-based agronomist Juliet Anderson, there was probably a sense of déjà vu following last Oct’s announcement confirming diquat wouldn’t be renewed, write CPM authors Lucy de la Pasture and Rob Jones in a recent article published by CPM.
“It seems to have been an open industry secret for the past two years that diquat would go the same way as paraquat and linuron, so now that we have closure, we can at least move on to look at alternative strategies for early weed control and address the potentially bigger headache of desiccation without diquat,” agronomist Juliet Anderson says.
With just over 20 years’ field experience as an agronomist, Juliet advises on 600ha of potatoes across Herefords and Glos, most of which are destined for the crisping and chipping markets. It’s a very challenging geographical area, where much of the rented land for potato production is sourced from livestock farmers, and Juliet is quick to acknowledge the problems in tackling a very broad weed spectrum when planning early season weed control.
“With its grace period officially over by next Feb, there’ll be a temptation to use diquat again in the same systems but, in my opinion, this must be the year to actively try new systems without it and get a proper feel for what works best,” she says.
While there are effective alternatives to diquat for early weed control, the bigger issue will be at the end of the season, believes Darryl Shailes, Hutchinsons root crop manager.
“Diquat is very quick at burning crops down, which has been great for preventing disease such as black leg from getting into tubers at desiccation. There currently aren’t really any comparable alternatives though, so this will add a further complication to management strategies post-2019.”