T3 - Protect the Quality

Fungicide Requirements

Fusarium and Microdochium control - Fusarium species cause ear blight which can significantly reduce crop yield and specific weight. They are also responsible for mycotoxin production which also affects grain quality and marketability of the grain.

Late season foliar disease control - T2 sprays typically provide 4-6 weeks foliar disease protection, in some situations this is not enough to keep the flag leaf disease free up to senescence.

Spray Options

The requirement of the T3 spray will partly be reliant on the level of disease control that has been achieved earlier in the season. New Aviator²³⁵_Xpro (prothioconazole + bixafen) gives more options for a targeted ear disease spray at this timing, whereas if more traditional chemistry has been used at T2 then there could be a need for a more general 'foliar top-up' spray at T3, to take care of any late season Septoria and rusts as well as ear diseases.

*Be aware that there is a higher Fusarium risk if prothioconazole is not a component of the T2 spray

Aviator²³⁵_Xpro contains bixafen and prothioconazole
Proline²⁷⁵ contains prothioconazole

Maintaining Grain Quality

High mycotoxin levels are associated with, but not exclusive to, delayed harvests. In a high mycotoxin year 2008, 29% of grain samples failed EU mycotoxin levels.

Good control of Fusarium ear blight is essential to keep mycotoxin levels low.  Trials with Harper Adams University College and FERA have shown that using prothioconazole throughout the programme is the best way of achieving this.

Source: 2008 HAUC factorial trial T1*T2*T3 with Proline²⁷⁵ 0.55 L/ha. Ground inoculum of Fusarium culmorum and F. Graminearum. High levels of ear disease achieved.

For Fusarium ear blight: Use a minimum of 0.55 L/ha Proline²⁷⁵ at T3 as the most effective control strategy. As the graph below shows additional management of Fusarium inoculum can be achieved at T1 and T2 using a prothioconazole based fungicide spray.

Source: 2008 HAUC factorial trial T1*T2*T3 with Proline²⁷⁵ 0.55 L/ha. Ground inoculum of Fusarium culmorum and F. Graminearum. High levels of ear disease achieved.

Application timing is important. Early to mid flowering is the optimum timing (GS 63-65). As the graph below shows it is better to be slightly early (GS 61) than slightly late (GS 70).

Source: university of Kiel, 2005.

For Microdochium: Control can no longer be reliably achieved using strobilurins. A minimum of 0.55 L/ha Proline²⁷⁵ has been independently proven to be the best option.

Topping up Foliar Disease Control

Where there are concerns around late season brown and yellow rust, add Folicur (tebuconazole) to Proline²⁷⁵

For Septoria: T3 sprays based on prothioconazole will continue to provide the best Septoria top up.

Further information about disease incidence and regional risk maps can be found at: www.cropmonitor.co.uk