Source: 2011 9 independent and 3 BCS trials.  Untreated yield 9.8t/ha and disease 37% L2

NEW: Comparative performance of new SDHIs on Septoria tritici

Glasshouse tests have been conducted to compare the relative performance 80% label doses of:

Aviator²³⁵_Xpro (1.0 L/ha) : 155g prothioconazole + 75g bixafen with Leafshield formulation system

Adexar (1.6 L/ha) : 100g epoxiconazole  + 100g fluxapyroxad

Seguris (0.8 L/ha) : 100g epoxiconazole + 72g isopyrazam

..on all key stages of the Septoria tritici life cycle, giving an indication of protectant and curative potential.

the graph below shows the relative performance of each SDHI co-formulation at different times after innoculation. Under optimum conditions Septoria tritici completes its life cycle in around 18 days - from spores landing on the leaf surface to clearly visible lesions with spore-producing pycnidia.

Surface growth                         Latency                      Necrotrophy               Pycnidium formation  

4 Days after infection Septoria is still largely growing on the leaf surface, and is an easy target for Septoria-active fungicides. As expected, all products are equally effective. This is what the disease looks like at this applications timing, magnified many hundreds of times.

Spores stuck to a wheat leaf hair in sticky "gel" following rain splash	Superficial hyphae growing on leaf surface around leaf hair and penetrating between cells

8 days after infection Septoria has extablished itself inside the leaf, but without causing any visible damage with leaves remaining green and healthy looking. This is called the latent phase, and is one of the trickiest fungicide targets and most important to control. The plant looks healthy, but the fungus can be running through the entire leaf, and can then switch to cause damage and form visible lesions is just 4-5 days. Here we start to see the differences in competency of the 3 SDHI co-formulations, with Aviator²³⁵_xpro the most effective, and Seguris the least effective. Aside from indicating degree of leaf systemicity, new formulation technology supports activity on this stage by facilitating entry through small leaf openings called stomata.

Latent Mycelium growing inside leaf between cells

11 days after infection Septoria is now starting to produce toxins which damage leaf cells, releasing the nutrients the fungus needs to start making pycnidia. Early lesions are recognizable in the field, and this is typically a field curative stage. Again, Aviator²³⁵_Xpro is more active than Adexar, and both are significantly better than Seguris.

Formulation of pycnidium inside wheat leaf opening,

or stomata, following plant cell death from fungal toxin secretion

14-16 days after infection. Septoria infections have progressed to the dry lesion stage with pycnidium formation (14 days) and maturation (16 days) with the start of production of new spore ribbons. This is a clear field curative situation and is a difficult fungicide target, requiring highly active fungicides supported by formulation technology to enhance uptake into both leaf and fungus. Aviator²³⁵_Xpro is more active than Adexar, offering about 10% better curative disease control, and both are significantly more active than Seguris. At this 80% label dose equivalence, Adexar would cost around 60% more than Aviator²³⁵_Xpro.

Spore ribbon extruded in sticky gel from a pycnidium beneath a leaf stomata

*Seguris is a trademark of Syngenta

*Adexar is a trademark of BASF

2011 9 independent and 3 BCS trials. Untreated yield = 9.8t/ha and disease = 37% L2

Source: Replicated FERA trial 2011, ground inoculum F.culmorum & F.graminearum.  Ear disease assessed GS 80, following noted treatments

*Tracker, Ignite and Comet are trademarks of BASF

** Seguris is a trademark of Syngenta

Source: 2011 AICC Bridgnorth, cv Oakley.  Overspray at T1 Opus* 0.5 + Comet200* 0.4 L/ha.  Untreated yield 7.2t/ha and disease = 92%

*Opus and Comet200 are trademarks of BASF

** Seguris is a trademark of Syngenta

Source: 2 Velcourt trials 2008 & 2009.  Untreated yield 9.98t/ha and brown rust 15%

NEW: Comparative performance of new SDHIs on Puccinia recondita (brown rust)

Glasshouse tests have been conducted to compare the leaf systemic activity of an 80% label dose of:

Aviator²³⁵_Xpro(1.0 L/ha) : 155g prothioconazole + 75g bixafen with Leafshield formulation system

Adexar (1.6 L/ha) : 100g epoxiconazole  + 100g fluxapyroxad

Seguris (0.8 L/ha) : 100g epoxiconazole + 72g isopyrazam

Brown rust was used as a test fungus, because Aviator²³⁵_Xpro is highly active on this disease (see above)

Product was applied at the base of leaves of growing plants held horizontally. A thin waxy barrier was created in front of the point of fungicide application to control against fungicides moving along the leaf surface, since Aviator²³⁵_Xpro is known to be a high-spreading formulation.

Experiments were conducted to evaluate speed of  systemic activity by treating plants, then inoculating the whole leaf with rust spores 24h and 3 days later. Leaves were photographed after 8 days when the untreated ones were expressing full symptoms and active spore release.

After 24h, the differences between products was clear. with Aviator²³⁵_Xpro keeping the whole leaf green, indicating full systemic movement within this short time period. Seguris was the next most effective product and Adexar the "weakest", with clear signs of early colony development and associated chlorisis. 

When fungicides were applied 3 days prior to inoculation, there was no difference between products suggesting that full leaf systemiciity was achieve by all the co-formulations in this time period, with differences being masked. However, the 24h test is the most critical in identifying rapidity of foliar acropetal systemic movement.

*Opus, Comet200, Tracker and Adexar are trademarks of BASF

*Seguris ia a trademark of Syngenta

Source: HGCA 2009 ½ label rates applied at T1 and T2

*Tern is a trademark of Syngenta

**Flexity is a trademark of BASF

***Talius is a trademark of DuPont

****Cyflamid is a trademark of Certis