Winter wheat growers will see top levels of control of the crop’s three main yield-robbing diseases next spring from a new broad-spectrum fungicide. This will give industry-leading efficacy against septoria, and both yellow and brown rusts.

The new SDHI active isoflucypram, also known as Iblon, comes from agrochemicals giant Bayer and will be marketed in Britain as Vimoy and available in a co-pack with the widely used azole prothioconazole (Proline). This twin pack will be called Ion Iblon.

See also: Cereals 2023: Two fungicides stand out in wheat septoria battle

Bayer says the new SDHI is structurally different from other SDHIs, giving it greater efficacy and a broader disease-control spectrum.
It will compete with other wheat fungicides such as Revystar, Univoq, Elatus Era and Bayer’s own Ascra in 2024.

The group will also launch a co-pack of Iblon and Inatreq for 2024 in a deal with Inatreq’s maker Corteva, aimed at the T2 flag leaf market.

‘Neck and neck’ performance

Septoria tritici on lower leaf of winter wheat © Blackthorn Arable

Fiona Burnett, professor of applied plant pathology at Scotland’s Rural College (SRUC) says Iblon’s performance against the three key diseases is “neck and neck” with the current leading products. So it is on a par with straights Myresa (Revysol) and Peqtiga (Inatreq) for septoria control, and Elatus Era for the rusts.

“It’s a broad-spectrum product, and at the front of the pack for the control of septoria, yellow rust and brown rust,” she told Farmers Weekly at an event for the launch of Iblon.

Diversifying chemistry with a new SDHI will bring benefits, but she warns that the farming industry is on the very limit of being able to manage disease in wheat, and growers need to pay attention to stewardship as part of their resistance management strategy.

She suggests reducing the risk of disease resistance to fungicides building up
by a good choice of varieties, drilling
dates and rotations. Growers should also reduce the reliance on individual actives, while using mixes of products and also alternating products.

“Sensible and stewarded use of Iblon is vital to retain it and other actives in the long term,” she says. Fiona is also chairwoman of the Fungicide Resistance Action Group.

New Zealand use

One grower who has already used Iblon is 73-year-old New Zealander and former world wheat record-holder Eric Watson, who farms 490ha of irrigated heavy silty land on the Canterbury Plain, east of Ashburton.

He was the first farmer to use Iblon after it was cleared for use in New Zealand in 2019. He achieved a 8% lift in yield of the disease-susceptible wheat variety Oakley on his high-yielding farm, where he averaged 15t/ha over 125ha of winter wheat last harvest.

His next step is to top 18t/ha and win back the world record, which he held at over 17t/ha until Tim Lamyman harvested a record-beating 17.96t/ha in the summer of 2022 on the Lincolnshire Wolds.

Michael Maue, Bayer’s R&D global project lead, says two factors stand out with Iblon. First, its unrivalled biological efficacy,
especially against septoria and yellow rust, and second its Leafshield formulation technology, which is already being used in the group’s Xpro range of fungicides.

Fungicide ring 

The Iblon molecule, discovered 15 years ago, contains a N-cyclopropyl ring at its centre and this enhances its activity and broad-spectrum effectiveness.

“Iblon is an SDHI but its structure is different and this gives it good broad-spectrum disease control,” Michael says.

Rosalind O’Hare, Bayer’s campaign manager for combinable fungicides, says in 2021 and 2022 trials Iblon outperformed Ascra, or products containing Solatenol, such as Elatus Era, for septoria control, and was on a par with both Revystar and Univoq.

On yellow rust, a 2021 University of Nottingham trial demonstrated that Iblon had greater curative and protectant activity against yellow rust than Solatenol, making it the best-in-class fungicide against this unpredictable disease.

Yellow rust © Blackthorn Arable

Broad spectrum 

In addition to septoria and yellow rust, Iblon also delivers excellent protection against brown rust and useful activity against eyespot. In combination with Proline, its activity against eyespot is further improved and its spectrum of activity extended to include fusarium and mildew.

The inclusion of the azole Proline supports Iblon’s broad-spectrum activity, while adding a second mode of action to ensure sound resistance management.

Its approval for use in Britain marks the first fungicide to be given the green light after Brexit, and means British growers will be the first in Europe to be able to use the new fungicide, and the second in the world, after New Zealand. Iblon will be limited to a single application each year on a crop of wheat.

Bayer has not yet given a price for the new product, but has said it will be competitively priced compared with other competing products.

Expert views

Brown rust © Blackthorn Arable

Experts welcomed the approval, with Jonathan Blake, fungicide specialist at crop consultant Adas, saying that Iblon is excellent on both yellow and brown rust and very good on septoria.

It is a more active SDHI on septoria than existing standards, and it will be a valuable addition at either the T1 or T2 timing, he says.

Dr Paul Fogg, crop production technical lead at agronomy group Frontier, says the broad-spectrum activity of Iblon came to the fore last season as it was a campaign of two halves, with septoria early on and then yellow rust later in the season.

Patrick Stephenson, committee member at the Association of Independent Crop Consultants, says the new fungicide will help growers maintain efficacy and provide additional protection of all the chemistry options.

Along with Ion Iblon, Bayer will launch a twin pack of Jessico One (Inatreq) and Vimoy (Iblon), which will be aimed at the T2 market in the UK.

The SDHI Iblon will be complemented by Inatreq, with its different site of action to the SDHI to help with resistance management.