A well-timed T3 ear wash spray could make all the difference this year in helping wheat crops reach their full yield potential, after what has been a very challenging growing season.

Agronomy group Hutchinsons believes that getting the timing right is crucial in protecting both milling and feed wheat crops from disease and building overall yields in the weeks leading up to harvest.

Sally Morris, one of the group’s agronomists, believes that the efficacy of T3 fungicides are often reduced because sprays are applied too late.

“Some people wait until flowering is well under way before applying the T3, but it’s too late by then. Fungicides should be applied as soon as ears complete emergence and flowering is about to start,” she says.

See more: Spray tips for battling ear blight in wheat

When making spray plans, growers are urged to consider the three important roles that T3 applications serve – controlling ear diseases, topping-up foliar disease control and extending green leaf retention.

Controlling ear diseases

David Ellerton

David Ellerton, the agronomy group’s technical development director, believes that T3s can focus specifically on controlling ear diseases, rather than topping up flag leaf sprays, if settled weather has allowed both timely and effective T2 applications.

He explains that fusarium and associated mycotoxins continue to be the main diseases to control, also highlighting that the weather during flowering can have a big impact on the level of disease development, so he advises growers to assess risks and tailor sprays appropriately.

Warm and wet weather during flowering supports the development of fusarium species – and where this could be an issue, Dr Ellerton suggests applying products based on prothioconazole, tebuconazole or metconazole.

Top-up foliar disease control

Although T2 fungicides should perform well during dry, settled conditions around flag leaf emergence, Dr Ellerton believes T3s may still be needed to bolster foliar disease control, especially against septoria.

Susceptible varieties will be at greater need of support, in cases where earlier sprays have been weakened, or if in the coming weeks unsettled weather results in greater disease pressure.

“Where Septoria tritici has not been fully controlled by T2, ear sprays should be based on products containing epoxiconazole or prothioconazole,” he adds.

Extend greening

Sally Morris

Both experts agree that adding a strobilurin at T3 stage will help in extending green leaf retention, especially as crops normally produce 60% of total biomass between flag leaf emergence and maturity.

“Anything that keeps crops alive and green canopies working for longer could make all the difference to yield by harvest,” believes Miss Morris, who would also suggest including magnesium with ear wash sprays where needed.