January 25, 2011
New wheat fungicide most suitable for high yielding areas
A T2 application of a new Bayer SDHI fungicide Aviator 235 Xpro will most likely to give a clear definite return from wheat crops harvesting more than 9.5 tonnes/hectare.
Analysis of 40 trials from three contrasting seasons from 2008 to 2010, by Bayer''s James Taylor-Alford found that sites with the highest yields showed the greatest additional response to Aviator Xpro over the current standard T2 of three-quarter dose triazole plus 80g/hectare of strobilurin.
Where trials yields, typically 15% higher than commercial yields, topped 9.5 tonnes/hectare, switching to Aviator Xpro increased yields by 4% or 0.45 tonnes/hectare over the commercial standard, Taylor-Alford, the firm''s product agronomy support manager, said at the product''s press launch.
Using Aviator Xpro at T2 at sites with a yield potential of 8-9.5 tonnes/hectare saw a 2% or 0.18 tonnes/hectare increase, while low-yielding trials with less than 8 tonnes/hectare yields only gave 1% or 0.08 tonnes/hectare response to Aviator Xpro.
"The best response is in high-yield potential crops where you see the benefit of the Aviator Xpro technology."
Perhaps surprisingly, the analysis suggested that disease pressure wasn''t necessarily the major factor in the increased response, with septoria levels in the untreated plots being relatively similar across low, medium and high-yielding sites.
"There appears to be something else other than just septoria control going on, probably akin, but not exactly the same as, the strobilurin fungicide physiological responses."
That said, it made sense to use the best products for disease control when pressure was high, he stressed.
Less surprisingly, high-yielding crops also produced the largest return on investment from switching to Aviator Xpro, which will cost GBP6-GBP8/hectares (US$9.60-US$12.80/hectares) more than current standards, he said. "The higher the wheat price the greater the margin delivered by Aviator Xpro."
For example, a farm switching to Aviator Xpro on 100 hectares of high-yielding wheat sold at GBP150/tonne (US$240.01) could see an additional GBP6000 (US$9599) income.
"But on low-yield potential crops there are more questions about switching," he admitted.
To achieve the yield benefits on high potential sites it was critical to use at least 1.0 litres/hectares of Aviator Xpro, he stressed. "There is a strong dose response with Aviator Xpro, and in trials we''ve found that if you drop the dose to 60% or 0.75 litres/hectares you''re not really doing anything you can''t do with existing chemistry."
Region and variety should be non-factors in any decision to switch. Six variety trials in 2009 and 2010 switched Aviator Xpro for Firefly at T2, and showed a fairly consistent yield response for the new chemistry, Taylor-Alford said.