Septoria worry as Scottish wheats hit T1
Septoria worry as Scottish wheats hit T1
UNSEASONALLY high levels of septoria are the main concern in Scotland as most wheats approach T1, say advisers.
SAC reference crops are showing 7% infection compared with an average 2% at this time of year. "That might not sound much, but it is a fair amount of septoria – and we are still expecting quite a high risk of eyespot," says plant pathologist Fiona Burnett.
Her comments are echoed by SAC Scottish Agronomys Huw Phillips working the length of the east coast arable area. "There is no shortage of septoria and eyespot levels are significant enough to be of concern."
T1 sprays should be geared to combating those diseases, probably with a triazole plus Unix (cyprodinil) mix, he says.
"The mildew control from Unix should be sufficient to deal with the amount of mildew we are seeing, even in Claire."
Despite some "leggy" looking crops most wheat will only be due a T1 spray in the next week to 10 days, he says. "The ear movement from the base of the stem is still quite slow."
Dr Burnett suggests 0.5 litres/ha of Unix should be included as "standard" this year at T1 with the rate boosted to 0.7-0.8 litres/ha on high-risk crops such as second wheats or early-sown first wheats.
Opus (epoxiconazole) as the triazole component needs to be used at a minimum of 0.5 litres/ha on all but the most septoria resistant varieties.
"You will need that to get control of the septoria and get to flag leaf."
Not going too soon with T1 sprays is also important, she stresses. Targeting leaf three, typically at GS32, fits in with the optimum timing for Unix and will reduce the kick-back required at flag-leaf when strobilurins come into SACs recommendations.
"Trials show they are more cost-effective at flag and ear timings and we are staying within FRAG guidelines." *
SCOTS T1 TARGETS
• Widespread septoria main target.
• Eyespot risk significant.
• Little mildew.
• Save strobs for flag and ear.