Keep spray costs in perspective, says agronomist
Growers planning wheat fungicide programmes should focus on the best products, says one of the region’s leading agronomists.
Fungicides constitute around 20% of variable costs but yield responses from a four spray programme are generally very good, averaging around 2.5t/ha (range of 0.5-5t/ha).
“Lower grain prices have focused the mind on where and when to spend,” said Marion Self of Prime Agriculture. “With the varietal and disease risks this coming season, the focus will need to be on using flexible and persistent products.”
Over 23 years of varying disease pressures, trials at The Arable Group’s Morley site had shown an average of 0.11t/ha response at T0 timing, 1.87t/ha yield gain from the combination of T1 and T2 sprays and 0.42t/ha from the T3 spray.
“To put the economic split into context, T0 should be around 10% of your spend, T1 33%, T2 33% and T3 24% of your spend. If you budget on £100/t for wheat and a fungicide programme costing £85/ha you’re going to need a yield response in excess of only 0.85t/ha to start earning a return on your spend.”
This is easy to achieve, so growers shouldn’t be afraid to apply “robust” doses to minimise the risk of rapid disease development especially in the event of unforeseen delayed applications.
“Getting it right is all about choosing the right combination of actives that have been trialled to prove a return and using them at the right timings.”
This year, rust risk is potentially high given the high percentage of the wheat area susceptible to common races of yellow rust. Growers should be sensible about the active ingredients they choose, making sure the rust risk is covered.
“In reality covering yourself with a robust rust defence is only going to cost you an extra 5% on your spend, so why risk rust in what could be a troublesome year? ”
Where appropriate, a T0 spray with a cheap triazole will suffice, but growers should make sure it has good rust activity. At T1, a triazole + boscalid + chlorothalonil as in a Tracker + Bravo or another Opus based programme will be a good option this year for Septoria, brown and yellow rusts and eyespot.
At a robust dose rate, Proline was also a good option on yellow rust as well as Septoria and eyespot. But growers shouldn’t get side-tracked by rust – Septoria remained the prime target.
“To put the risk into perspective, the only new variety on the HGCA Recommended List with a Septoria rating over 7 is Warrior. The rest rate 6.7 or less, ranging from KWS Sterling at 4.7 to Alchemy at 6.7 with popular Oakley ranking at 5.5.”
