Blog •  11/05/2022

Decisions to be made as flag-leaf sprays are readied

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By Mike Ashworth, Cereal Fungicide Product Manager 

In a typical wheat-growing season, the priority from mid-May to early June is to ensure a solid T2 spray takes care of the key diseases that will stop the crop reaching its potential in the coming weeks.

There are always variables that influence which product to choose, and how much to apply.

But there are an increasing number of factors at play for UK growers to weigh up in the coming weeks.

First, and most importantly, is assessing the disease threat.

Most arable farms would be glad of some rain at present; a cold, damp start to the year was followed by an unseasonably dry spring. These conditions leading up to T2 applications would usually mean lower disease pressure.

However, septoria hasn’t been hard to find when walking fields so far this year, and a sustained rainfall event would immediately heighten pressure. There are also plenty of reports of explosions of yellow rust, even among the most tolerant varieties.

Reports from plant sample PCR tests carried out by SwiftDetect show a surprisingly high presence of latent septoria, and looking back to this time last year, the rains came around the T2 fungicide timing.

Weather conditions are important now, but they are arguably more important in June when sprays have been applied and your chosen fungicide has to do its job. It is protecting a crop from disease in the future more than in the past.

Unfortunately, none of us know what the weather will do or what the disease threat will be. Against this backdrop, decisions to delay spraying or reducing rates could be risky.

Second, growers will be looking to protect the value of their crop. At the time of writing the price of feed wheat is still well in excess of £300/tonne, and with crops drilled in good conditions last autumn, there is potential for favourable yields.

With the ‘agflation’ experienced by arable farmers over the past 12 months, the income from this year’s harvest will be needed to help balance the books, following the additional investment in inputs required to grow cereal crops.  

Third, rates will need careful consideration.

For a product such as Univoq, there’s dose-rate flexibility to tailor applications to pressure. The label rate of 2l/ha rate will rarely be needed, and we would advocate a starting point of 1.25l/ha, but that can be adjusted up or down according to the variety, the location, and the known disease pressure.

A variety with a strong septoria score being grown in East Anglia, for example, may be sufficiently protected with 1.1l/ha, while a more susceptible variety grown in a wetter, warmer part of the country might warrant 1.5l/ha.

So Corteva’s advice to those making final decisions on product choice and rates this May and June is to choose a robust fungicide which delivers proven results and can be flexible to your needs.

For those who didn’t try Univoq when it was launched last year, it delivers a powerful combination of curative and persistent protection against septoria plus a broad spectrum of other diseases, including rusts.

Univoq being sprayed at T2
Univoq being sprayed at T2

Useful links

For more information on how Univoq works, and the results of the 2022 trials, watch this short video

Blog: Investing in yield protection makes even more sense this year

Blog: What we learnt about Univoq™ fungicide in 2021

Univoq microsite - latest news/resources 

Univoq product page - full technical information