DAERA Notes: Crops

Winter barley disease control

Apply T2 fungicide three to four weeks after T1, ideally when the flag leaf and the first few awns have emerged. For crops that pose a high lodging risk include plant growth regulator (PGR) in the mix and apply earlier before awns emerge when the final PGR is more effective at shortening the straw.

The best performing fungicides contain an SDHI and Triazole, (for example Aviator, Adexar) Strobulurin (for example Priaxor) or a mix with three different modes of action, for example Ceriax or Concorde and Rubric. Prothioconazole with a Strobilurin, for example Fandango or Mobius also gives good protection if the crop is clean. Inclusion of Chlorothalonil at T2 provides best control of Ramularia normally only evident towards the end of the growing season.

Winter wheat disease control

Prepare for a timely T2 treatment at flag leaf emergence no later than four weeks after the T1 spray. A well applied T2 spray will give a bigger yield response in wheat than any other spray timing.

Triazoles continue to lose their activity against Septoria and remain most effective when used in a protectant situation as part of a mixture with an SDHI. You must use SDHIs responsibly as part of fungicide programmes which minimise potential selection for resistant Septoria strains. Only use SDHIs where necessary, never apply more than twice in a season, keep up dose rates and always use in combination with a multisite protectant, for example Bravo or Phoenix and a Triazole fungicide.
SPRING CEREALS

For recently sown spring cereals the option still exists to apply residual herbicides more commonly used on winter cereals pre or early post-emergence as extensions of minor use (EAMUs). These herbicides provide a different mode of action and improve annual meadow grass control.

If crops are too far forward for the residual option, aim to apply a mixture of at least two broad spectrum herbicides whenever most of the weeds are at the two to four leaf stages. This ensures weed competition is removed at an early stage of crop development and may allow product dose rates to be reduced.

It is also good practice to prevent disease becoming established at this stage by tank mixing a fungicide with your herbicide. As Rhynchosporium is the most damaging disease in our current spring barley varieties, product choice should reflect this. Products previously mentioned for winter barley are equally effective on spring barley, although at a lower rate.

Nitrogen top dressing is best applied once tramlines are visible at the two to three leaf stage (GS 12 to 13). Later applications than this may green the crop but add little yield.

POTATOES

As planting progresses it is important to ensure good quality seed beds are produced. Check periodically to ensure correct planting depth and spacing are being achieved.

Have plans in place for early weed control to ensure key timings are not missed. Where pre-emergent products are used checks crops regularly to ensure herbicides are applied on time to avoid crop damage.