Growers urged to check wheat13 March 2019
Be prepared to inspect wheat crops regularly to assess lodging and disease risks through March and April, a leading northern England agronomist is urging.
According to Nigel Scott, regional technical manager for agronomy firm ProCam, winter wheat crops drilled early last autumn are showing forward growth and early signs of Septoria and yellow rust infections.
“How disease develops from this point forward through the spring will depend on the weather,” says Mr Scott. “It’s not time to panic but earlier drilling will have allowed a longer period for infections to build.
“Ultimately, it’s a balance between not letting disease get out of hand if it needs attention, but also not applying the first fungicide of the season too soon.
“If you do apply it early, it’s also tempting to bring the next spray forward. This will result in stretched spray intervals at some point of the season, leaving crops exposed to disease if fungicides can’t provide a sufficiently long period of control.”
In response, when building a fungicide programme, Mr Scott says he prefers to count backwards from the main fungicide timing of the season, the flag leaf or T2 spray applied around mid-May, to the T1 spray applied to leaf three about three weeks before this, and back to the T0 spray, applied in late March at the earliest, or more often into April.
“By doing this, it helps weigh up the disease risk in relation to when the T0 fungicide is likely to be applied,” explains Mr Scott. “That way, you can judge whether you can wait that long or whether something needs doing sooner. Sometimes it can require an additional spray.
“Ultimately, you can’t be prescriptive with fungicide programmes. You have to walk the land and assess the situation on a field-by-field basis, taking into account other risk factors, such as how susceptible the variety is to disease and how responsive it is to fungicides, then draw up a programme based on all the information.
“From a lodging risk viewpoint, although early-drilled crops are forward, crops look well-rooted after the dry autumn and winter. This should help with anchorage in the soil. However, overall crop growth will still need assessing properly for the T0 timing, when decisions on plant growth regulators and fungicides are made.”
Maintaining healthy crops through the season by applying micronutrients and bio-stimulant treatments little-and-often with the fungicide programme has also produced some substantial yield gains over recent years, Mr Scott concludes.