A NEW survey has suggested that more than two-thirds of farmers think that the early bird T0 fungicide spray in winter wheat is now more important than it was five years ago.

The survey, carried out on 100 cereal growers by Syngenta, showed that 68% of respondents felt this way, mainly due to the fact that septoria tritici and/or yellow rust have become more difficult to control if not prevented early enough.

This was followed by 29% saying they had bigger crop areas to spray and that T0 gives some ‘insurance’ against T1 delays. Despite this, 17% of respondents cut back on a T0 in winter wheat in 2016.

Syngenta cereal fungicide campaign manager, Andrew Curtis, said: “The key point with winter wheat disease control nowadays is that we have to take a more preventative approach.

“Shifts in the sensitivity of septoria tritici to the curative effects of azole fungicide chemistry mean it has become more difficult to regain control later if allowed to establish. Similarly, we saw last year just how quickly the latest yellow rust races can develop, and how difficult they can be to get back under control.”

With all these issues, he added that T0 provided a timely way to damp down over-wintered infection: “Even if crops appear clean at T0, which is typically in March or early April, it is impossible to accurately predict future disease pressures.

“For example, new trial results from 2016 in what was a high pressure situation, showed yield was increased by 0.7 t/ha across three different winter wheat varieties from a T0 application of the chlorothalonil plus azole treatment, Cherokee. That was despite a robust follow-up fungicide programme being used.

“As the survey highlighted, you also have to consider the benefit of having applied a T0 if your follow-up T1 fungicide is delayed. T1 and T2 fungicides, which protect the main yield-building leaves, give better results if applied to clean crops.

“The chlorothalonil treatment Bravo is a popular option at T0 against septoria, but if there’s a risk of rust as well, you’re going to need more than this. Cherokee is cost-effective because it provides a high loading of chlorothalonil plus two leaf-mobile azoles – including cyproconazole which is noted for its yellow rust activity.”