Article taken from Farmers Guide, June 2017
Spring barleys have been slow to get away in my area of Wiltshire. Most were drilled into very dry seedbeds and received no rain for several weeks.
Some crops emerged well, but they have developed very slowly and were still tillering in mid-May. The rain has since transformed them, and they are now racing through their growth stages.
A close eye will be needed to hit the correct T2 fungicide timing in the spring barley. This application should be made when first awns are visible (GS49). Last year most crops were sprayed in early June, but I suspect they will be later this season.
Some crops suffered variable emergence, where seeds went into such dusty seedbeds they didn't realise they had been drilled!This has led to a range of growth stages in the same fields. We'll have to assess when most of the field is at GS49 and then spray.
I'll use Jaunt (fluoxastrobin + prothioconazole + triflo xystrobin) at 0.5-litres/ha plus Arizona (folpet) or another multi-site to protect against rhynchosporium, net blotch and rusts. All are likely to be present after the recent unsettled spell.
Spring barley can often run short of magnesium and sulphur. I'll add some Headland Magnus to enhance chlorophyll production and help maximise grain fill. I'll also add Velocity, an adjuvant that improves coverage of the leaf surface , aids uptake of active ingredient into the plant and reduces drift.
Winter wheats have also perked up and, although shorter than usual, still have potential . My growers maintained a robust SDHl/triazole/chlorothalonil T2 programme and this has stood crops in good stead
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T3 ear sprays are imminent , and I'll be recommending Monkey at 1-litre/ ha. This product contains prochloraz + tebuconazole, both of which have good activity on fusarium and michrodochium fungi that produce mycotoxins in grain.
These actives will also control septoria , rusts and sooty mounds. These diseases can reduce grain filling and specific weights if they get onto the ear.
The ear spray should be applied between GS61 and 65, the start of flowering to mid-flower. Growers adopting a wait-and-see approach with their T3 should apply one within three to four days of a rainfall event within that period.
The spray is best applied through backward-facing medium or coarse nozzles to optimise coverage of the vertical ear target.
Most wheat crops will now be past the danger period for orange wheat blossom midge, when the ear is emerging and before flowering. Later susceptible varieties should be assessed for thresholds, by counting adults on warm (+15°C) still evenings - one midge per three ears on feed wheats, and one per six for milling varieties - or by using pheromone or sticky traps.
If crops do exceed the treatment threshold, apply lambda-cyhalothrin or Biscaya (thiacloprid) preferably during the early evening when the adults are active.
Maize crops have been late to germinate, and some growers opted out of pre-emergence sprays, thinking they wouldn't have been as effective with the dry conditions.
Post-emergence weed control will now be key. Young maize is very uncompetitive and needs to be kept free of weeds to optimise development - maximum yield potential is fixed by the 6-leaf stage . Weedy crops are also more straggly and shallow -rooted , increasing the risk of lodging later on.
Elumis (mesotrione +nicosulfuron) at 1-1.5-litres/ ha provides good broad spectrum activity.
Maister (foramsulfuron + iodosulfuron) can be used instead to control single R-resistant black-grass, adding Buctril (bromoxynil) as necessary to boost broad-leaved weed control.
Esme Shephard is an agronomist with Agrovista, based in Wiltshire (esme.shephard@agrovista. co.uk).