Crop Watch: Cool, wet weather means delay to grassweed spraying

Recent cooler, wetter weather is likely to mean that many growers will wait until the spring before using the key grassweed herbicide Atlantis (iodosulfuron + mesosulfuron), according to reports from FWi’s regional agronomists.

Temperatures down to -6C in Gloucestershire last week (w/e 25 November) were not conducive to using the product, Neil Donkin said. “We need the blackgrass to be actively growing before spray application.

“Pre-emergence herbicides seem to be working well so far and it may be that the bulk of Atlantis applications will wait until the spring.”

But the situation could change, he added. “It is recommended soil temperatures should be at or above 6C for a week prior to using Atlantis. We could get back to that given a few mild days.”

Where pressure from blackgrass was low, and/or plants were small, spring applications of Atlantis or Pacifica were also planned in East Anglia, Will Foss said.

“Atlantis will be applied this side of Christmas only where blackgrass is fully emerged and at high competitive levels. In borderline conditions, it will be vital to ensure coverage is maximised by using a fine quality spray applied to a dry leaf.”

Kent-based James Boswell said there had been a range of herbicide timings this autumn, due to good spraying conditions, but pre-em applications had worked best. Atlantis applied in the last three weeks also seemed to be working well, he noted.

“With soil temperatures dropping to 5-6C, now is a good time to use Kerb (propyzamide) or Crawler (carbetamide) to control difficult grassweeds [in oilseed rape],” he added.

Most fieldwork had drawn to a close for the winter in East Lothian, and crops looked well, AICC agronomist and farmer, Andrew Riddell concluded.

“Mid-September sown oilseed rape looks very respectable with good root growth and sufficient leaf canopy, although pigeons could be a problem on some sites. Cereals generally look well, although slugs have been difficult to contain on some ploughed sites.”

  • This is the last Crop Watch for 2007. Reports will resume in February, in time for the spring campaign.

To read any of the reports in full, click on the links above, or select one of the following regions:

North (Andrew Riddell)

South (James Boswell)

East (Will Foss)

West (Neil Donkin)

Cropping query? Why not post it on FWi’s Crops comments forum?

Online grain trading made easy with Farmers Weekly Graindex

It takes just a couple of minutes to create a listing on Farmers Weekly Graindex and you’ll get a range of prices to compare from active buyers who want your grain.
Visit Farmers Weekly Graindex