New fungicide Aviator Xpro promises higher yields

Bayer CropSciences new SDHI fungicide has given a higher yield response than top triazole products in three years of HGCA appropriate dose fungicide trials.

Plots treated with bixafen product Aviator Xpro from 2008 to 2010 returned average yields of 9.4t/ha compared with nearest rival Brutus at 9.2t/ha.

Jonathan Blake, senior research scientist for ADAS, says impressive septoria control is probably the main reason for this response, but he thinks there could be other unknown effects.

Yield responses varied over the three years with all products giving reduced responses when disease pressure was low, he says. "From the results, there is same rank order between the products when disease risk is low, but the numbers are smaller."

Because the trials are designed to test the products in a worst case scenario, Mr Blake says the results may not translate to field conditions. "This is an extreme test of product efficacy. It gives growers and agronomists information to understand efficacy of active ingredients and products on specific diseases, but yield differences wont necessarily be the same in the field."

Aviator Xpros curative and protectant activity against Septoria tritici was greater than straight Proline or Opus, giving similar control to triazole mixture Brutus, says Mr Blake.

It also gave good control of brown rust indicating bixafen and/or the formulation added useful activity compared with prothioconazole alone. But due to low disease pressure in 2010, data was only available from 2008 and 2009.

Brutus and Opus gave the greatest activity against yellow rust, but Aviator Xpro did give good control of the disease, particularly when used at more than half the label rate.

In a mildew trial in 2009, Aviator Xpro gave a comparable level of control to the leading mildewicides such as Tern and Flexity. Each product was applied at half rates to Claire wheat at T1 and T2 timings.

The trials, managed by ADAS, The Arable Group, Scottish Agricultural College and Teagasc used susceptible varieties planted in high pressure locations with products applied once at rates from a quarter to double label rates.

bixafen was only tested in a mixture with prothioconazole, but the activity was judged by comparing efficacy with straight Proline. At full rates Aviator Xpro contained slightly less prothioconazole than Proline so any improvement in the efficacy of the mixture can be attributed to the addition of bixafen and/or an improvement in the product formulation, says Mr Blake.

The tested formulation of Aviator Xpro is slightly different to the Aviator 235 Xpro product that will be sold in the UK which will contain an additional 10g/litre prothioconazole, he concludes.

• Active ingredients: Aviator Xpro (bixafen + prothioconazole); Opus (epoxiconazole); Brutus (epoxiconazole + metconazole); Proline (prothioconazole); Tern (fenpropidin); Flexity (metrafenone)