THE IMPLICATIONS of leaving blackgrass untreated could be more significant than you think, according to results from Masstock trials.

Leaving just one blackgrass plant uncontrolled in the spring can cost up to 44kg/ha of lost wheat yield, the Cambridgeshire trials using Hereward winter wheat last year suggest.

“A population of some 12 blackgrass plants per square metre is therefore generating a yield loss of over half a tonne per hectare,” said the firm‘s trials manager, David Newton.

Growers still have time to control blackgrass this spring and he urges anyone doing so to treat crops sooner rather than later.

“Blackgrass this year is more advanced than last year because of the dry autumn in 2003. So it will be more competitive and harder to control this spring.”

He recommends applying Atlantis (mesosulfuron-methyl + iodosulfuron-methyl-sodium) as soon as possible.

Last year‘s trials found that applying Atlantis on March 31 – when blackgrass had six tillers – gave a yield of 11.03t/ha, some 0.35t/ha less than the December timing.

But, delaying application until mid-April, with the weed at growth stage 29, gave a yield of 10.72t/ha, he noted.