Beat cereal stress and benefit

Conducted using the strobilurin azoxystrobin - contained in Amistar and Amistar Opti, and the discovery of which was inspired by naturally-occurring fungicides found in woodland mushrooms - the research has shown additional effects on top of disease control in both field and laboratory tests.

With disease pressures high this season and climate-induced stress often a problem, such combined effects could be particularly useful, experts suggest.

According to Syngenta global researcher Dr Jeremy Godwin, pictured, even despite Septoria tritici resistance in wheat, strobilurins continue to boost yield. Indeed, with UK cereal prices having risen from around £60 to £90/t, that extra yield has become even more valuable, he adds.

The typical 0.4 t/ha extra yield seen over the last three seasons from adding Amistar to a triazole fungicide programme has risen from £24 to £36/ha in value, he calculates. While a 0.7 t/ha yield increase from Amistar Opti - which also combines the activity of Bravo against Septoria tritici - has risen from £42 to £63/ha, he adds.

"Clearly, we know Amistar and Amistar Opti boost yield by protecting against key diseases such as rusts, Septoria nodorum, take-all and ear diseases - and these diseases are likely to be important this year. But we also know that crop stress effects are significant," explains Dr Godwin, "for example the link between stresses on barley plants and physiological leaf spotting.

"As well as looking at disease control, these studies also focused on other benefits from strobilurins - in laboratory tests, field trials and even filming differences in how a crop loses its green leaf. Yield isn't just about disease control, it's also about maintaining green leaves to maximise the products of photosynthesis available for grain-filling. Therefore, such information is important for growers' fungicide decisions," he adds.

"We have studied carbon dioxide assimilation - the photosynthetic process which fixes carbon into carbohydrates in the plant. We found carbon dioxide assimilation was increased by Amistar. The benefit of this is more carbon is fixed in the form of carbohydrates which can be stored in grain."

Dr John Reade of Harper Adams University College in Shropshire, who has conducted two years of research into Amistar and Amistar Opti on reducing crop stress, is convinced these are genuine effects.

Examining the impact of stresses caused by reduced light, reduced nutrient availability and drought on spring barley, he looked at the effects of various fungicides when applied to stressed and non-stressed plants during June at T2.

As well as good disease control across both seasons he found stressed plants treated with Amistar and Amistar Opti mixed with a triazole suffered less leaf death or senescence.