Trial plots reveal fungicide’s added growth regulator effect

WHEAT growers looking to respond to improved grain prices by minimising yield losses from lodging could do so by augmenting their traditional growth regulator programme with the added lodging reduction of an early season fungicide, trial plots suggest.

This is based on research by leading farming company Velcourt over two seasons which showed that including the fungicide Cherokee in a disease control programme could also cut winter wheat lodging by up to 90%.

“There are definite crop height reduction properties of cyproconazole which result in reduced lodging risk”

James Alford, Field trials manager, Velcourt

According to Velcourt field trials manager, James Alford, the reduction in lodging from Cherokee comes from cyproconazole, one of its triazole active ingredients. As well as activity against Septoria tritici and rusts, it also has spin-off growth regulatory effects.

“There are definite crop height reduction properties of cyproconazole which result in reduced lodging risk,” explains Mr Alford.

“I was very surprised at the large reduction in lodging. The crop was under so much lodging pressure, the untreated was completely flat. The main reason for using a triazole is disease control." This augments rather than replaces a PGR programme, he adds. “It is another feather in its cap.”

Linked to this reduced lodging, Mr Alford says Cherokee also gave corresponding increases in yield.

Last season, while untreated plots averaged 21.3% lodging with a yield of 6.58 t/ha, plots treated with 2.0 l/ha of Cherokee at growth stage 31 (GS31) had just 8.7% lodging and yielded more than 1.5 t/ha higher at 8.13 t/ha.

By comparison, plots treated with a prothioconazole plus chlorothalonil fungicide mix at GS31 in the absence of a PGR programme averaged 22.9% lodging with a yield of 7.77 t/ha.

By using 1.5 l/ha of Cherokee at GS 31 preceded by 1.25 l/ha of Cherokee at the earlier T0 timing of GS 30, lodging was reduced to just 2% – equating to a 90% reduction versus the untreated – with yield boosted to 8.66 t/ha.

“The yield would have been directly related to lodging,” continues Mr Alford. “The more lodging, the lower the yield.

“We are big T0 advocates in Velcourt. My view is Cherokee fits that slot. The real benefit is if you put a T0 on in March and you get a poor April and can’t get a T1 on. It gives you insurance,” he adds.

Besides looking at the anti-lodging effects of Cherokee applied alone, Mr Alford says Cherokee was also assessed when applied with regular PGR programmes – based on two different doses of Moddus. Although less obvious than when used alone, additional crop height reductions could still be observed over the PGR programmes, he notes.

Chris Rowsell, technical manager of Syngenta, who sponsored the work, agrees this is a useful extra Cherokee effect. “With cereals so valuable this season it makes sense to do the best job possible to keep crops standing,” says Mr Rowsell. “With its activity against rust, anti-resistance properties against Septoria tritici, and good value, Cherokee already makes a good fungicide option for wheat growers. Although we don’t suggest replacing traditional PGR programmes with Cherokee, these bonus PGR effects give extra peace of mind and come at no extra cost.”

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