Corteva Agriscience is set to issue new advice to wheat growers, having completed a six-month investigation into problems associated with its Inatreq-based fungicide Univoq.

Some growers experienced issues with sprayer components last season after applying fungicides containing the active ingredient Inatreq at T2 spray timing.

See also: Cereals 2022: Corteva’s scrutiny of sprayer damage continues

There were reports of damage to nozzle seals and pump diaphragms during T2 applications of Inatreq, which left some growers with hefty repair bills for sprayers.

Agrochemical giant Corteva has carried out an extensive investigation into the formulation and the circumstances under which issues occurred.

In a statement, it said that no single factor had emerged as a root cause of the sprayer problems, adding that claims that Corteva’s Inatreq active was the sole cause of these failures were “not proven”. 

“The investigation began in May 2022, when reports were received by Corteva Agriscience claiming that some sprayer components were being affected when Inatreq was among the tank-mix constituents.

“But in mainland Europe, more than 1m hectares were successfully treated, with only one sprayer requiring attention, and in the UK, the majority of users were unaffected.”

Corteva investigations also ruled out any question of faulty batches of Inatreq being produced.

Good sprayer hygiene and maintenance

As an aid to growers, Corteva is set to publish best-practice guidelines for next year.

These will address the need to use the “most resilient component materials” when replacing sprayer parts, and to practise good sprayer hygiene and regular maintenance.

In particular, the advice will recommend spray concentrations of not more than 0.7%, and advise against using the products in pulse-width modulated spraying systems.

Spray water volumes should also be at a minimum of 200 litres/ha, and products containing Inatreq should not be left in the sprayer tank overnight.

Growers will also be advised to replace existing pump diaphragms on sprayers to those made of ethylene propylene diene monome (EPDM) rubber or Blue flex.

Market supply

According to one arable adviser, who asked to remain anonymous, Univoq is still a very useful product, though he said he could understand why growers who had experienced problems might be wary of it.

Moreover, the active Inatreq would be needed to avoid market shortages at T2 spraying time.

“We need different actives. If it is just Revystar, Ascra and Elatus, the market won’t be able to cope without such a big player as Univoq,” the source said.

“It is unlikely, with more crop in the ground this year, we are going to have enough product from all the other manufacturers.

“If you do decide to use it, the key thing is being thorough with the hygiene. Don’t let anything stand in the sprayer overnight and rinse out the tanks and lines properly at the end of each session of using.”

Univoq was approved for sale and use in the UK in March 2021 – the first fungicide with a new mode of action targeted at septoria strains to be registered for 15 years.