E-Malt.com News article: UK: Barley disease prevention places importance on T1 fungicides timing

Barley growers cannot afford to take their eye off the ball when applying T1 fungicides, despite recent settled weather across much of the UK helping to slow disease development, say agronomists, according to Farmers Weekly, April 6.

"The T1 on barley is equivalent to the T2 in wheat in terms of importance," says Ben Freer from The Arable Group. While crops in northern England and Scotland are a week or two away from the T1 timing, many growers further south started applications earlier this week, he says. "Disease levels aren't enormous, but you can find a bit of everything, from net blotch, rhynchosporium and rust. There isn't a vast difference between varieties."

Fandango at half to three quarters rate (0.5-0.75 litres/ha), or a Proline/Kayak mix are the main products being used, he says, with rates adjusted according to disease pressure and varietal susceptibility. "Kayak is an improvement over Unix if rhyncho is established, as it's more effective at knocking it out," he notes.

Northumberland-based Robert Sullivan also says a wide spectrum of disease is present, although optimum T1 timing is still about a week away. "Disease pressure is higher than normal, as we've had no winter to speak of." Particularly unusual is the presence of brown rust in both wheat and barley. "We never usually see any at this time of the year up here. But, if you're using a good T1 product at a decent rate, it will take it out."

New product

He suggests applying 1 litre/ha of Fandango plus 0.25-0.3 litres/ha Corbel, although the new product, Kayak, in mix with Galileo (formerly Acanto) may be used to see how it compares. "Last year we probably wouldn't have gone past 0.75 litres/ha Fandango, but this year we'll use a full litre, plus the Corbel to make sure we get complete clean-up."

Rhynchosporium is coming in to most varieties in East Lothian, according to AICC agronomist and farmer, Andrew Riddell. With the majority of barley around growth stage 30, a T0 of cyprodinil, morpholine and manganese was applied earlier this week and T1's are likely go on around mid-April, he suggests. "If a T0 has been applied, we'll probably go with Kayak and morpholine at T1, but if not, Proline plus morpholine or Kayak should give a heavier hit.

"Strobs are still active against rhyncho, so depending on your budget, you could include them," he adds.

Mr Riddell says a lot of fresh mildew was seen in February, but levels have fallen recently thanks to drier weather.

In North Yorkshire, it is wet weather that indirectly reduced mildew pressure, says Patrick Stephenson. "We didn't get nitrogen on until very late and the discolouration killed a lot of leaves, which helped eliminate the disease."

But "normal" levels of net blotch and rhynchosporium are present in susceptible varieties and T1s are scheduled to go on this weekend. "Most net blotch is on the six-row varieties. Saffron is a bit cleaner than Pearl." All crops will get prothioconazole in some form, at about half rate, he says. "Fandango tends to win for its simplicity and all-round disease control." Galileo, chlorothalonil or Kayak may also be used on some crops, depending on specific disease pressure or variety weaknesses.


06 April, 2007