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Revus performance to tackle new blight strains

Potatoes
22.04.2021
Early potato emergence

Results from latest independent Eurofins blight field trials have once again shown that blight fungicides containing the highly effective active, mandipropamid, performed exceptionally well - even with inoculation of more challenging and aggressive blight strains, including EU_36. 

For the third consecutive year the unique trials protocol, designed to truely tease out active performance, has shown the performance of Revus has been maximised with the addition of a drift retardant in the tank mix.

Eurofins blight trial spraying

Syngenta Potato marketing manager, Mark Britton, highlighted the addition of Crusade with Revus has shown to reduce the risk of drift and improve spray deposition throughout the crop canopy – enhancing performance of blight control.

He reported that, for the first time, the Eurofins trials in 2020 were physically inoculated with the more aggressive blight strain 36_A2, along with Pink 6, Blue 13 and Green 37 – representing a broad spectrum of the most common UK blight isolates.

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“Results from 2020 confirmed no concerns with the efficacy of Revus against all the blight strains in the test, including 36_A2 which increased as a percentage of the general late blight population from 2019,” he said.

Mark Britton

In untreated plots blight infection started to take hold towards the end of July, and developed very quickly to complete destruction of the green leaf by the third week of August. All the blight fungicides performed well up until early September, when differences clearly started to become apparent.

“Under the trial’s artificially intense blight pressure, of the fungicides that were tested, the Revus + Crusade was the stand-out result for keeping blight at the lowest level in the trial plots,” Mark advised.

With the nozzles used for the Eurofins trials being quite drifty, it is believed the addition of the drift retardant is helping to get more fungicide into the canopy and working more effectively.

Eurofins trials

Using an assessment of AUDPC (Area Under the Disease Progression Curve) gives the best picture of season-long product performance, where Revus + Crusade clearly showed the lowest infection of all the products on trial.

That very much confirmed the results seen in the intrinsic activity trial run in 2019, added Mark.

New trials for the 2021 season are set to evaluate the use of other drift retardants in combination with Revus.   

Trial strengths

Mark Britton pointed out the season-long single product treatment protocol used in the Syngenta trials at Eurofins, involving 11 applications in 2020, was designed to better assess the true intrinsic activity of fungicides, compared to using them in a programme where individual strengths or weaknesses could be masked.

It would also better flag up any potential issues of changing product performance to shifting blight populations from season to season, he suggested.

“This trials format has confirmed the efficacy of Revus against all the blight isolates in the field, and just how to maximise its performance in practice.”  

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