Faster growth speeds up the need for inputs

Crop drive on: May sunshine has transformed most crops over the past two weeks. Nutrients have begun to flow as seen by the good colour now in most crops. This time last year we had many fields with yellow areas caused by wet.

Winter crops: Winter barley crops are a bit later than normal but they will catch up. Potential still looks good, with most crops quite clean. Winter wheat crops will quickly move towards T2 to be applied once the flag leaves are fully emerged, regardless of the timing of the T1 spray. Consider any final N on winter wheat (40-60 kgN/ha) in the coming week(s) as the flag leaves emerge.

The T2 on winter wheat should contain robust rates of triazole, an SDHI and a contact. Where possible alternate the triazole active used at T1. Any of the four main SDHI combinations can be used but you may need to strengthen the triazole. Include chlorothalonil also. While research indicates that cross resistance is likely in SDHIs, I would still change the SDHI active between treatments.

T2 treatments could be either Adexar, Librax, Aviator, Seguris, Treoris or products with broadly similar actives to include a different triazole to that used at T1.

Final sprays on winter barley can be applied from awns out to ears emerging. This can again be an SDHI or a strobilurin plus triazole plus a contact. Again, alternate actives where possible. Final sprays may include products like Bontima, Siltra, Ceriax or Treoris mixes. All final sprays must include chlorothalonil or Phoenix.

Where possible, hold final sprays on oats until ears are out. If you need a stop-gap, consider a straight triazole like Folicur or Opus. Final spray options include products like Lumen, Furlong, Fandango or Opera.

Spring crops: The heat has made a big difference to crops which have largely shed that recent winter look. Early planted barley crops are now at the end of tillering so weed and disease control and insecticide should be applied. Insecticide may not be needed on these early crops.

Herbicide should include an SU, or a mix of SUs, plus a contact or hormone partner. You may also need to treat wild oats or canary grass now. Take care with mixes and sequences when using Axial – do not mix with hormones.

Apply growth regulator to spring wheat at the start of stem extension. This can be as simple as CCC – 0.8-1.0 l/ha of a 75% product. With spring oats apply first PGR between GS32 and GS32, using either CCC or Ceraide.

Last week on page 51 I indicated that Cerone could be used on spring barley. This was an error – this product has no clearance for use on any spring cereals.

All nitrogen should now be applied to all spring crops.

Watch spring rape for the presence of significant numbers of pollen beetle. Treat if necessary with products like Karate or those containing cypermethrin. Avoid unnecessary spraying due to the possible presence of resistance.