Crop Watch: Variable spring barleys and weed control in potatoes

This week, our agronomists discuss the variability of spring barley crops, with some having patchy emergence and are struggling.

And in Scotland, potato planting is nearing completion and the focus is now on the timing of crucial residual herbicides.

See also: New wheat variety shows resilience over a testing season

South

Oli Pilbeam, CCC and CLM (Kent and Sussex)

Most crops are looking well on the heavier land, despite the lack of rain, Shame I can’t say the same for the lighter, shallower soils.

I’m particularly surprised at how spring crops have held up. It helped that the barley and oats were drilled early, in March, into damp seed-beds.

But even the later planted peas and maize, have found some moisture – helped by being drilled deeper than usual. 

At the time of writing, we’ve had only about 5mm in the past month. We could do with a nice slow, gentle 30mm. Not that I’m being picky.

On lighter land, there will be some yield penalty as a result of the dry conditions. There is also some barley yellow dwarf virus (BYDV) kicking about, despite a two-spray programme in the autumn. 

Tailored T2

As there was a lack of disease when we formulated our T2 herbicide programmes, we opted to take a more tailored “spray as we see it” approach rather than “we’ll spray it anyway”.

The T2 programme on 60% of the wheat was, therefore, cheaper than usual, adopting prothioconazole plus tebuconazole and/or azoxystrobin.

We took a “belt and braces” approach on the other 40%, where it was drilled earlier, has more yield potential and was showing disease on leaf four. 

By effectively applying my T3 at the T2, we might end up with a cheap £60-£70/ha total fungicide spend across the whole season, but should septoria start increasing (more likely if we’re lucky enough to get some rain) we can switch to belt and braces chemistry as a T3.

Meanwhile, brown and yellow rust is now bubbling around, but the blended varieties are doing a good job of keeping it down.

I’m a big advocate of utilising various box packs available from different distributors, offering significant savings.

If you have the same branded delivery van coming down the drive through the season, you won’t be getting the best product selection or price.

Fertiliser prices remain a worry. Some farmers have already sourced 60% of their requirement, possibly with extended payment terms, buying peace of mind by knowing it will be on-farm in June or July.

I believe that was a smart move. The ability to do this depends on cashflow – and, with my consultancy hat on, I’m having more conversations than ever about this.

With more working capital needed, it’s worth reconsidering machinery financing, overdrafts and loans.

Entering an HP or contract-hire agreement, or taking a fixed-term loan and generating cash that way, are ways of potentially releasing much-needed capital. 

East

Ryan Baker, Frontier (Suffolk/Norfolk) 

The recent break in the weather has come just in time for many wheat crops. However, the rainfall has been very variable with some crops still struggling.

Discussions about T2 flag leaf applications have centred on crop potential and disease risk.

Adepidyn (pydiflumetofen), Inatreq (fenpicoxamid) and Revysol (mefentrifluconazole) could all feature, depending on local conditions.

Some crops are particularly tall and will justify a later growth regulator, especially where irrigation has featured.

Thistles and wild oats have been the key weeds this spring and their control is still being considered at T2 where emergence has been late.

Contending with high daytime temperature and May night frosts has been challenging.

Barley can be more susceptible to late frosts than wheat as the crop starts to flower while the ear is still in the flag leaf sheath.

The rain has brought useful moisture to enhance activity of clethodim in sugar beet. Early broad-leaved weed control has worked well, especially where intervals were kept tight.

Frosts have also made timing spraying challenging, but crops are growing away rapidly where they have established well.

Initial flea beetle grazing seems to have subsided, but has caused noticeable damage to some fields. Aphids were not as prevalent as expected early in the season.

It has taken much longer to reach threshold than initially feared, with many crops only receiving their first acetamiprid this week.

Spring barley

Continuing the theme of variability, some spring barley crops looks fantastic and have covered the ground well, and are now stem extending. Others have patchy emergence and are struggling.

The dry weather has resulted in minimal weed emergence in many crops.

Spring beans are close to first flower and look clean so far. Winter beans that had early chocolate spot infection now look well and have grown away from any early disease.

With pods starting to form, thoughts have turned to a second fungicide concentrating more on bean rust.

The first tranche of vining peas have had any emerging blackgrass controlled successfully. Where pigeons have been kept at bay, the crops are even coming into flowering.

Azoxystrobin will be utilised at cream bud. Time will be spent carefully assessing the crop for any potentially virus-carrying aphids.

Maize was drilled to a sensible depth into moisture this spring and is emerging very well. At 4-6 true leaves, ahead of buttress roots forming, crops are likely to receive a post emergence herbicide to minimise crop competition.

West

Dominic Edmond, Matford Arable (Devon/Cornwall)

A lot of work has been done in the field since my last Crop Watch report. Winter wheat and winter barley T2s have been applied while nearly all the maize has been drilled and is emerging.

There have even been further crops of spring barley planted in the past two weeks, which seem late in terms of the calendar, but for this peculiar spring, it doesn’t feel totally wrong.

The last two to three weeks have been cool, with some beastly north-westerly winds that haven’t relented. There has been plenty of sunshine, but little rain (15mm) since the last report.

Thankfully, the cool conditions have slowed the growth of the winter crops which, in light of minimal rain, has prevented them from getting too drought stressed.

It also means that septoria levels in wheat have held, but with rain showers about, there is the potential for it to start recycling again quickly.

Previous experience has shown the risk of getting lulled into a false sense of security and that getting the T2 flag leaf spray right is critical.

Consequently, wheat has received a Miravis Alpha (pydiflumetofen)/Prosaro (prothioconazole + tebuconazole) fungicide, with its superior septoria control invaluable, particularly if June turns into a scruffy, wet month weather wise.

Winter barleys received T2 applications at awns tipping, with an increasing use of folpet in mixtures for ramularia. Most crops look like they have some promise.

Getting fertiliser applications correct around rain events this year was important, and the better-looking crops are the ones that achieved that, and also where two aphicides were applied in the autumn.

Thin crops

Really good spring barley crops are few and far between, the cool conditions have slowed them up, with a number looking thin and unless significant rain appears in the next days, they have the potential to disappoint.

Maize went into good seed-beds and was planted relatively deep to grab what moisture there was. Most of my growers were dissuaded from rolling, unless they had poor seed-beds.

With most crops emerging and pre-emergence herbicides applied before recent moisture, and with the promise of warm conditions next week, it means they will start to motor and will need walking for any post emergence herbicide requirements.

Fodder beet has also emerged, and with mainly dry conditions recently, cabbage stem flea beetles have been active, so recommendations are going out for control of the pest and many emerging broad-leaved weeds.

North

Greg Dawson, Scottish Agronomy (East Scotland)

Winter wheat T2 treatments are getting under way in the most forward cops, but there is significant variation in crop development between locations and varieties.

Close attention to detail is required to get the timing right and ensure adequate protection of leaves one and two.

In 2024, fungicide responses in the north were driven by sustained septoria pressure and in 2025 yellow rust dominated.

Both were impacted by breakdowns in varietal resistance combined with weather conditions that suited each disease almost perfectly.

It remains to be seen what the defining characteristic of 2026 will be.

Unsurprisingly, yellow rust is now present in untreated trial plots of a range of varieties, but commercial programmes are largely keeping symptoms at bay.

It is less clear what influence septoria will have on the result at harvest.

Rainfall amounts are variable across the northern cropping area, but is likely to have been adequate to allow overwintered infection to progress up the plant.

Currently, low temperatures are leading to a long latent period. All but the very earliest drilled crops remain free visually from symptoms down to leaf four, but rises in temperature may undo this early optimism.

Given the generally unsettled forecast and the limited varietal resistance, sensible insurance will be required to protect the substantial sunk costs.

The practicalities of hitting spray timings in with the broken weather pattern will also impact on the result.

Potato planting

Potato planting is nearing completion in all areas, and the focus has shifted to the timing of crucial residual herbicides to get ahead of challenging weeds.

Crop emergence has not been particularly rapid up to this point, but broken weather conditions can rapidly lead to challenges for the very limited post-emergence options.

Some growers are looking to the future by implementing programmes without metribuzin in anticipation of a further reduction in the pre-emergence toolbox through product revocations.

Local trials information is very useful in optimising the more complicated mixes required to the specific weed pressures.