The cold snap should stop most oilseed rape crops from requiring a second spray for phoma this autumn, say agronomists.
“You can see quite a lot of lesions on some of the big crops, but most of these will have been treated and don’t warrant a further spray, a) because of the frosts and b) because of their size,” says Essex-based TAG Consulting agronomist Andrew Blazey.
North Yorkshire AICC agronomist Patrick Stephenson agrees.
“If crops have had one spray the cold weather should be sufficient.”
But the recent cold snap might pull forward treatments in early spring, he believes.
“On the very forward crops growers will see what leaf material survives the winter and as a precaution spray, probably with something which also has growth regulator activity.”
Smaller, more backward crops could still need spraying this autumn, he points out.
“Last year we saw some damage on those types of crops.
At least, because the mild weather has encouraged those crops to fill out a bit, it is easier to justify spraying them.”
Growers spraying a fungicide can safely tank mix propyzamide, says Agrovista’s Mark Hemmant.
“But manufacturers won’t back a three-way mix of fungicide, Kerb and a contact graminicide.”