For this reason, control programmes are designed principally for Septoria, with the other diseases such as eyespot and Fusarium head blight specifically targeted as required during the season.

Now that the reductions in sensitivity of Irish S. tritici populations to the azoles observed in the lab can be widely seen in their field performance and with the ever-present threat of resistance developing to the SDHIs, there is a growing concern as to our ability to control Septoria into the future.

As Irish wheat crops have the potential to be world beaters in terms of yield, it is essential that this looming threat is addressed.

To do this, all aspects of production must be looked at and tweaked if possible to reduce the burden of control currently placed almost solely on fungicides. It is only through such an integrated approach to control that we will be successful.

Deciding what, where and when to plant should always be the first decision when controlling disease. Rotation is regarded as the most basic cultural control strategy. While limited in what it can do for foliar pathogens, it is essential to reduce levels of diseases such as eyespot and take-all.

Once the decision on what to plant has been made, deciding what variety can then influence future disease levels. Even though potential yield will often be the deciding factor, the disease-resistance profile of a variety must be taken into account and used accordingly.

For example, matching the disease resistance of variety for the riskiness of getting to spray at the ideal T1 and T2 timings will provide a built-in level of flexibility often required at these timings. Such riskiness could be as simple as having off-farm parcels of land which may take extra time to get to. Similarly, matching varietal resistance to sowing date will reduce levels of inoculum which will build up over the winter.

While such approaches alone will not prevent yield losses, they will provide a foundation from which a fungicide control programme can commence.

The most important aspect of any fungicide programme is ensuring the fungicides are applied at the correct time and in as close to the right conditions as possible.

The bulk of wheat yields are created by the final leaves, so ensuring these remain free from disease is vital. Once the potential has been protected, it is then important to protect it from infection from diseases such as Fusarium. To achieve both of these, the timings of fungicides on wheat (T1, T2 and T3) have been developed in such a way as to maximise the activity of available fungicides.

Main application

The first main application, T1, is timed to correspond with the emergence of the final leaf three. By doing so, it provides the protection of leaf three and part of the final leaf two.

In addition to protecting potential yield benefits from leaf three and leaf two, this protection then provides a barrier for the movement of spores upwards through the crop as it extends. Also, as the crop is only commencing stem extension, eyespot control can also be achieved.

The second application, T2, timed to correspond with the emergence of the final leaf or flag leaf, provides the protection and curativity of the most important leaves contributing to grain filling (leaves one and two). The final application, T3, timed to correspond with flowering, protects the ear from Fusarium infection while topping up Septoria protection on the upper leaves.

As the above timings require the applied fungicides to provide protection, and given Irish climatic conditions also strong curativity, the choice of fungicide product is critical.

However, in addition to providing effective disease control, programmes must also be designed to promote the longevity of the different fungicide actives through the use of sensible anti-resistance strategies.

As the most effective products such as the SDHI and azoles can be required at T1 and T2 in most crops, the exception being resistant varieties sown late in the season, it is essential to use them in effective mixtures.

It is important to always mix the SDHIs with an effective partner fungicide. In wheat, this means an azole or azole mix, but also the inclusion of a multi-site such as chlorothalonil or folpet is a must in all applications targeting Septoria.