Graeme Marshall

Graeme Marshall

Tackling wheat disease threat head on

Darfield-based arable farmer Graeme Marshall has taken a proactive approach to fighting the impact of speckled leaf blotch – also known as Septoria tritici blotch (STB) – on his wheat yields.

STB has been present in New Zealand for many years, but recently has become the main foliar disease attacking wheat. In some cases, it can reduce yields by 50% or more. “An integrated approach that incorporates variety selection, management practices, crop rotation and fungicides is the most effective way to manage STB,” he says.

Graeme and Gill Marshall farm 250 hectares (ha) on their west Canterbury irrigated property, with an emphasis on seed crops; but also includes dairy grazing and wintering lamb as part of their farming programme.  Last year, the Marshalls grew a wide variety of crops including: wheat; barley; ryegrass; white clover; peas; browntop; fescue – as well as some maize silage and vegetable seed crops.

With the threat of SLB a growing problem in New Zealand wheat crops, Graeme decided to try Bayer Crop Sciences’ new fungicide treatment Aviator Xpro during the 2014 season – after the discussing the issue with his local PGG Wrightson rep.

According to the Foundation for Arable Research (FAR), SLB is now the principal disease affecting New Zealand wheat crops. Over the past four years the disease has developed resistance to a fungicide group which, until recently, had been most effective in controlling it. These fungicides are commonly known as strobilurins.  FAR’s research also highlighted the importance of the succinate dehydrogenase inhibitor (SDHI) foliar fungicides, which are unaffected by strobilurin resistance.

Aviator Xpro is a dual combination fungicide that combines the Prothioconazole fungicide, (DMI), with a powerful new fungicide called Bixafen (SDHI) and is ideal for reducing resistance; it is highly effective against SLB in wheat. Another feature is its Leafshield™ technology, a patented formulation designed to ensure the product strongly adheres to the leaf and spreads and dries quickly. Graeme says the Aviator Xpro was applied via ground early to his wheat crop – at the T1 stage— in an effort to stem any impact of a possible SLB outbreak. “Its (Aviator Xpro’s) good SLB activity helped us achieve yields averaging between 8 and 12 tonnes per hectare; over the 64 ha of wheat we grew here last season,” he explains. For the coming season, things are looking okay at this stage. The wheat was in the ground and in good time, but Graeme thinks SLB could still be a potential threat – depending on how the season turns out. A cold, wet winter/spring is likely to see a greater chance of the disease appearing. “But we could do with some really good rains before spring,” Graeme adds.

Meanwhile, if SLB does look like being a threat, Graeme Marshall will again take a proactive approach and use Aviator Xpro to keep any impact of the troublesome disease at bay.