Late-season protection helps reduce disease build-up

• Risk to crops despite dry weather

• Green leaf retention remains key

• How to protect harvest potential

Growers who take action to protect cereal yields against unexpected increases in disease will reap the rewards at harvest.

Risk-modelling shows an increased threat from septoria spores across much of the country following the important flag leaf (T2) timing, says Syngenta fungicide technical manager Jason Tatnell.

Although this spring has been very dry, previous years have shown septoria can be a challenge later in the season – not least because septoria spores are spread by splashes after rainfall.

“You only need to remember 2019 – when June downpours sparked a sudden Septoria onslaught in what had previously been a low Septoria season – to realise this,” says Mr Tatnell.

Green leaf area

Syngenta’s new Miravis Plus fungicide technology set new benchmarks in septoria situations prior to its limited launch last season. Mr Tatnell says it has underlined its performance in trials ahead of its increased T2 availability this year.

“The key point to remember about T2 is its purpose is to protect crop green leaf area against disease during the critical yield-building phase.

“There might be 10 weeks between T2 in May and harvest, and every extra day that winter wheat flag leaf green area can be kept above 37%, yield increases by 0.15t/ha.

“For greater yield certainty, the T2 fungicide therefore not only needs to provide powerful disease control but also long-lasting protection.”

Extra confidence

In line with this, Mr Tatnell says when new Miravis Plus fungicide technology arrived on the scene last season, it set new standards for yield in septoria situations and in several key barley disease scenarios.

Now, new trials from 2024 in readiness for its increased availability in 2025 have underlined its responses, and should give growers extra confidence, he adds.

“Pre-launch trials between 2020 and 2023 showed a Miravis Plus-based treatment delivered in 0.3-0.5t/ha over competitor fungicides, with this performance advantage confirmed in the most recent AHDB fungicide performance results.

A T2 application of Miravis Plus + Era (prothioconazole) in wheat has also resulted in reduction in fusarium head blight and in DON mycotoxin, says Mr Tatnell.

Targeted protection

Using Miravis Plus + Era at T2 can make it more likely that a suitable T3 fungicide will keep the crop below a DON threshold.

If rust is a concern, this can easily be targeted by adding Amistar to Miravis Plus + Era,” he adds.

In barley, Mr Tatnell says a Miravis Plus-based treatment has also given visibly improved green leaf area protection against net blotch and rhynchosporium, while ramularia control has been one of its standout benefits.

“Similar to the trend we’ve seen in wheat trials, results in recent internal and independent trials in barley in 2024 also confirm a yield advantage from a Miravis Plus-based treatment of up to 0.5t/ha over competitors,” he adds.