August 1, 2014
Septoria challenges September wheat drilling
Increasing Septoria challenges are fast making September drilling as much of a problem for wheat growers in the west of the country as black-grass already is in the east, according to the latest results from Agrii’s Western Technology Centre. To such an extent that it is becoming uneconomic across large parts of the country.
More than 300 growers and agronomists attending the summer event at the 18 hectare trial centre at Aldbourne near Marlborough came face to face with this reality in a highly visual study of the interactions between variety, sowing date and fungicide regime.
Even with a well-timed T0, Septoria pressures over the past season have been so great that the disease has proved almost impossible control on all but the most resistant varieties sown in mid-September. And even with Crusoe – rated a good 6 for Septoria tritici resistance on the current Recommended List – infections have only been kept at bay with a robust, full fungicide programme.
In contrast, untreated plots showed a dramatic reduction in infection levels across all varieties from late October sowing. Good Septoria control has proved possible here on varieties like KWS Santiago with a poor 5 resistance rating. And, in the case of Crusoe, even without a T0.
“We can still get reasonable disease control from September sowings providing we choose a resistant variety,” Agrii regional technical adviser, Tim Horton told event visitors. “But it may well cost £200/ha in fungicides which is far from sustainable at current wheat prices.
“This season I’ve heard of too many cases in which £150/ha or more have been spent on fungicides without sufficient Septoria control. With full rates of epoxiconazole or prothioconazole now giving only 30% curative control on average, stacked triazoles, multi-site protectants and SDHIs have become essential, making control increasingly costly and dependent on getting timings spot-on.
“In many parts of the west and north we simply have to take a more integrated approach to control involving effective cultural measures in just the same way we are with black-grass across much of eastern and southern England.”