While those crops planted in the early autumn are the worst affected the disease is certainly not confined to early drilled crops with those planted in May also affected.

The recent weather with heavy rain, mild temperatures and plenty of wind is ideal for Septoria to spread.

Heavy rain physically splashes the spores around the canopy whereas windy weather allows adjacent leaves within the canopy to rub together and for Septoria spores to directly transfer from leaf to leaf.

The mild temperatures have enabled Septoria tritici to complete its life cycle quite quickly and now many plants are showing sporulating lesions. In some cases these are already quite high up in the canopy.

With the flag leaf emerged on many wheat crops now is the time to make sure it is well protected against disease infection.

Just remember the top two leaves of a wheat plant along with the ear provide around 90 per cent of the final yield and we need to

strive to keep these leaves free of disease for as long as is possible.

To date the focus has been on Septoria tritici with most wheat crops escaping infection by rusts, which is possibly due to the large proportion of the crop now treated with Galmano seed treatment.

However, rust diseases remain a key threat and we must remain on our guard against them getting established.

If growers haven't already done so now is the time to apply flag leaf fungicides. Apply a robust mixture of Proline and a strobilurin

fungicide such as Twist.

As a fungicide group strobilurin products exhibit a lot of variation and Twist has been proven to be particularly effective against

Septoria tritici.

By mixing Proline with Twist growers not only attack the disease with two effective fungicides but as each product has a different

mode of action they are applying a responsible anti-resistance strategy.

Unfortunately this isn’t the end of the story as a further fungicide application will be required around three to four weeks after the

flag leaf spray was applied. Again it should be a mixture of Proline and a strobilurin fungicide but as leaf rust is more of a threat as temperatures increase a greater range of strobilurin fungicides could be considered.

For more detail contact your Bayer CropScience regional sales manager.