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Ryegrass survey reveals growers control challenges

Customer Insights
22.07.2019
Ryegrass heads above wheat
New results of this season's herbicide trials at the Ryegrass Focus Site have highlighted valuable extra performance from higher rates of pre-emergence applications to reduce ryegrass seed return

Around 60% of UK growers have a problem with ryegrass issues on their farms, with a third reporting the situation is getting worse, according to a Syngenta State of the Nation Survey of the weed and issues it causes.

“Ryegrass has typically been viewed as the lesser problem to black-grass,” said Syngenta grass weed manager, Cat Gray. “But we know that it is both more competitive to cereal crops and is getting increasingly difficult to control.

“This survey has shown the true extent of the ryegrass challenge, and sought to evaluate how well growers believe the control measures available are working to tackle populations.”

Cat Gray

Cat (above) highlighted that around 17% of growers reported an Integrated Crop Management (ICM) approach was beginning to take effect to lessen the burden, but only 10% felt they had ryegrass well under control with significant improvements.

Of the ICM measures utilised by growers to tackle ryegrass, spraying off heavily-infested crop patches was viewed as the most effective control option, followed by more spring cropping. Roguing out plants was seen as useful by a significant number (36%), but an equal number saw it having limited effect in their situation.

Find out how increasing Defy rates in pre-em applications reduced seed head returns

Ploughing equally had a mixed view in having any beneficial effect, but there was a more positive response to delayed drilling as a management tool. There was also a strong trend (45%) to increased herbicide stacking providing an effective response.

“The survey showed that 64% of growers do specifically select herbicide options to target ryegrass, with over half targeting selected areas with the approach," reported Cat.

However, 35% of growers still view ryegrass as just part of the farm’s grass weed programme.” The results revealed pre-emergence herbicides were performing more effectively (56% good or highly effective) compared to post-emergence treatments (32%). 

Ryegrass seedlings

“This finding chimes with results of new trials at the Syngenta Ryegrass Focus Site, in Yorkshire, where the pre-emergence Defy stack, in combination with flufenacet and DFF, achieved over 95% ryegrass control in a challenging infestation,” she advised.

Identifying Ryegrass issues

Around half of growers currently map the extent of their farm’s ryegrass populations, with another 20% now recognising the issues and intending to do so in the future, according to the survey results.

“We also found that 13% of growers had tested and confirmed herbicide resistance in their ryegrass, with a further 28% suspecting resistance from reduced herbicide efficacy,” she highligted.

“90% of respondents considered an in-field herbicide resistance test for ryegrass would be useful, depending on cost for many,” Cat added.

The Syngenta State of the Nation Ryegrass Survey covered 71 growers and agronomists from across the country, with the vast majority farmers from virtually all areas of the UK. The eastern counties (29%) and south east (12%) were most widely represented, along with significant numbers from the north east (15%).