Crop Watch: T0s approach in barley and an OSR weed issue

The T0 timing is fast approaching in earlier drilled winter barleys in the South, which are showing some disease after a wet winter. 

In Scotland, OSR weed control has not gone according to plan with the poor weather combined with the 1 March pesticide cut off date creating a bit of a headache.  

See also: Yellow rust early warning sensors to be trialled in-field

West

Dominic Edmond, Matford Arable (Devon/Cornwall)

My first Crop Watch report of the year, thankfully, coincides with an improvement in the weather, which after a week of walking winter barley crops, was a relief.

Devon and Cornwall, along with most parts of the country, have had a very wet winter. What is pleasing though, is that the crops have come out of such a wet winter looking very well.

The excellent drilling period last autumn meant crops went into good seed-beds and were well established before the onslaught of rain.

There is evidence of barley yellow dwarf virus on the fields that didn’t get an aphicide, but most are fine.

Nearly all the cereals I have seen have held their colour, other than the very wettest parts of some fields, indicating good crop establishment and reasonable soil N despite potential leaching over the winter.

Most barley crops are at just the stage you would want them to be at the beginning of March, mid-tillering, but not getting too far ahead of themselves.

Whereas some wheat crops are motoring, with some of the earlier drilled already at growth stage 30.

Being that the winter has been so wet, there is no surprise to see significant rhynchosporium in barley crops (some mildew too) along with Septoria tritici in wheat.

Barley T0 sprays

The barley crops will start to have T0s applied in the next  seven to 10 days.

These will be Prothiconazole/tebuconazole products along with K2 (chlormequat), plus or minus, a herbicide to tackle overwintered weeds and growth promoters where appropriate.

A lot of barley crops have had their first top dressing of nitrogen and sulphur, supplying half their nitrogen requirement. The end of March/beginning of April will see their balance added prior to the T1 spray.

Some wheat crops have had a small dose of ammonium nitrate to “wake them up”, with most of the first dressings due in the next 10 days before T0s which will be applied before the end of March.

Septoria being the number one disease in the South West, means T0s feature on nearly all my wheat crops, while also keeping an eye out for the yellow rust threat.

The weather this spring has resulted in no drilling of spring barley thus far. Looking forward, the weather will be catchy for a while yet, so any drilling is likely to be a challenge.

The hope is that when the catchy conditions relent, we then don’t go into a prolonged dry period.

South

Justin Smith, Procam (East Sussex)

There’s a famous saying that claims, “if March weather comes in like a lamb, it will go out like a lion”.

With the T0 fungicide timing rapidly approaching, let’s hope the only thing that needs taming is the current global unrest and not any further negative climatic events.

Most crops in the South East can be described as frothy, with their potential needing careful management.

This is a marked departure from last season, and although appetite for expenditure on cereal crops is low, we don’t want crops to fall at the first hurdle.

Last year’s mild autumn, followed by the wet start to the new year, means disease pressure is already high, so a robust approach will be needed to safeguard yield from the effects of septoria and rusts which are already present in some of the usual suspects.

Unlike last year, most of my winter wheats will receive a T0 fungicide: the exact course of action will be determined by the variety being grown, with an appropriate rate of azole and strobilurin chemistry applied as necessary.

Growth regulators

In many crops, early growth regulator applications will be needed to thicken bases and shorten internodes. A measured approach using cost-effective trinexapac-ethyl and chlormequat should cover most eventualities.

A wise colleague once said that by encouraging cell wall strength and rooting, trinexapac-ethyl is also one of the best solutions to help mitigate eyespot.

Autumn applied pre-emergence herbicides seem to have worked well, but unfortunately some brome and ryegrass is now starting to appear and will need to be controlled before early nitrogen and sulphur applications.

Alongside the suppression of grassweeds, Atlantis Star (iodosulfuron + mesosulfuron + thiencarbazone) and Pacifica Plus (amidosulfuron + iodosulfuron + mesosulfuron) also offer a useful array of broad-leaved weed control.

The strong autumn has reduced the spring sown area, with many growers now looking at other options.

Taking market prices and fertiliser supply issues into account, there seems to be little appetite to drill spring barley or oats, so I’m advising spring beans as a lower input option with the added benefit of its nitrogen fixing properties.

Hopefully, if there is a silver lining to be found in the latest round of international conflicts, the global instability will help to highlight the precarious nature of our small island’s food security and encourage prices to rise.

East

Rory Kissock, Farmacy (Essex, Herts, Cambs and Suffolk)

Here in East Anglia spring is trying its hardest to appear after what has been a very wet January and February, with rainfall for the two months combined being about 240mm.

In general, most crops have emerged from a mild, wet, winter looking very good, with the odd exception of late-drilled cereals behind sugar beet.

Pre-emergence herbicide applications have worked well in combination with delayed drilling and the grassweed pressure at present is low.

The normal bad areas will always have a few survivors, and these should be checked to see if any follow up treatments are required.

Yellow rust is fairly easy to spot in the susceptible varieties and especially those which are later drilled.

T0 fungicide programmes will be based around azole and strobilurin chemistry, ensuring an adequate dose is applied will give longevity to reach the T1 timing.

Getting the balance of rate vs return this year is going to be even more important than usual due to higher input costs and lower commodity prices.

Cutting product rates to save money in the short term might well cost you in the long run.

Septoria is also present in the base of most wheat crops (except those very late drilled) this will need watching as we move through March into April.

Hopefully, a warm dry spell will help reduce disease pressure – we can only hope.

Barley tillers

Winter barley has enjoyed the warm winter and produced a healthy number of tillers; retaining these is crucial for achieving high yields. Well timed growth regulators such as trinexapac can help with canopy manipulation and tiller survival.

Brown rust can be found in most crops and may, in the worst cases, require an early application of an azole to knock this back before coming in with the main fungicide and plant growth regulators programme.

Oilseed rape crops have slowly been moving throughout the past few weeks, and stem extension is now happening in most crops.

The most forward crops may well benefit from an application of growth regulator using either trinexapac or mepiquat-chloride + metconazole, these will manipulate canopy structure and reduce risk of lodging.

Foliar nutrition at this timing has proven to be of benefit focusing on magnesium, manganese and boron.

Winter beans are under high pressure from early infections of chocolate spot due to the warm wet winter. Earlier drilled, more forward crops are much more susceptible than later drilled crops.

The chemistry to treat this is limited and we don’t have anything curative, so applications will only be protectant to the new foliage.

Boscalid and pyraclostrobin can be used now, tebuconazole can be used, but ensure you check product labels and specific timing restrictions, generally from growth stage 40 – first flower buds onwards.

North

Mary Munro, Munro Agricultural Consultancy (East Lothian)

The first days of spring were thrilling as we emerged at last out of the dark, wet gloom into sunshine.

The following days have been frustrating though, and while most winter crops have had some nitrogen, spraying has been less straightforward.

Many winter wheats are well on, and will wait for the first N applications. The backward ones have had a small amount to get them going. Generally, crops are green and there are very few bare patches. Wheat T0s are a little way off yet.

Winter barley and winter oats are also looking good. There has been a little mildew, but over all the disease levels are not high, and no emergency action is necessary.

OSR weeds

Oilseed rape is a different story and the weed control has not gone as planned. A mild wet back end prevented Kerb (propyzamide) going on before Christmas.

Fortunately, a cold snap into the new year gave an opportunity, but we are now looking at perhaps missing Korvetto (clopyralid + halauxifen) where it was planned.

By the time you read this it will either have been sprayed or abandoned.

The tiny window between 1 March and buds visible is always a challenge and it is frustrating in the extreme to miss it.

The crops have had a bit of grazing by pigeons and deer, but ground cover is reasonable. There is a bit of light leaf spot in some crops and this may end up being treated later.

Preparation for spring crops is progressing with less hassle – green cover crops being sprayed off and some of the earliest farms in my area cultivating for beans.

Soils are turning over drier than expected. Spring beans will get imazamox, pendimethalin and clomazone pre-emergence.

Spring barley for malting is a major crop in these parts, and the lack of optimism in the whisky distilling sector is a big deal. Our local maltings has closed down, and contracts are hard to come by.

There has been a lot of debate about alternatives, and outlets for oats are also very limited.

The other options are break crops such as beans, potatoes and veg – it will be interesting to see how many growers stick with barley and hope for the best.