Crop Watch: Septoria alert drives fungicide planning

Septoria is being seen in many crops and Patrick Stephenson highlights that more susceptible wheat grown north of the Humber is “plastered in disease.”

Marcus Mann reports that septoria is also prevalent in the East and Kevin Knight adds that there is a lot more septoria than he would like to see on crops in the South, which will be the focus of the T0 spray next month.

See also: Video: How to properly set up a crop sprayer

However, it’s not just wheat facing disease pressure – in the West, Giles Simpson is looking to get a robust T0 on winter barley crops, as they are full of brown rust and mildew.

North: Patrick Stephenson

AICC (Yorkshire)

patrick stephenson

One of my clients summed this winter’s weather up really well when he said: “For a dry time it’s awfully wet.”

The ditches have hardly any running water in them, yet the fields are very sticky and each welly can carry several kilogrammes of sticky clay.

In recent days, I have gone from three coats, a silly hat and thick trousers to walking around in jumper and jeans with a real hint of spring in the air.

I am very lucky that during the course of a working month, I will talk to farmers between Stamford in the South and Berwick in the North.

This large geographic spread can cover a multiple of niche weather patterns, which in turn affects drilling dates, crop stages and disease levels.

This year it would appear that wheat grown above the Humber – largely drilled in September – looks really well, but the septoria-prone varieties are plastered in disease.

Those below the Humber tend to have been drilled in October and look OK, but not brim full of septoria. Therefore, the disease control programmes could look very different between the areas.

Crop walking in recent days has highlighted manganese-deficient areas, and excellent levels of weed control on the whole. No spring-germinating broad-leaved weeds or wild oats have appeared yet.

This year there will not be a rush to apply nitrogen and sulphur, as crops look so well. Growers are relaxed, however, as we all know this will soon change when the first fertiliser spinner breaks cover.

Winter barley crops have also benefited from the winter weather so far. Disease is starting to build nicely and so is the likelihood that a T0 spray will be required.

Flea beetle

The dreaded flea beetle has affected some oilseed rape crops in the south of the region, but overall they are very good, ranging from triffid-like to perfect.

Early nitrogen will still have to be applied as this contains the all-important sulphur. The overall total will be determined by how much biomass we have by the end of February.

Large crops, scientifically measured by the distance up my welly, will have between 50-80kg less than the standard. In theory, this could reduce the nitrogen to less than 100kg, but I am not yet brave enough to go below 150kg.

Light leaf spot is now visible in some crops and the treatment of this disease is causing me some consternation. I now feel the effectiveness of the azoles is being challenged and even the non-azole alternatives may be of limited use. Do we need a complete rethink of our approach to this disease?

Not since 2012 have we had so much ground to be drilled in spring. This is a combination of blackgrass control measures and disillusionment with either second wheat or rape. This will be a real challenge if the weather turns against us.

East: Marcus Mann

Frontier (Essex)

Marcus-Mann

It feels as if winter has left very quickly this year, with daytime temperatures rising by 10C last week.

However, a bit of sun on the back makes it easy to become complacent and soil temperatures have a way to go just yet.

Winter wheats, particularly later-drilled crops, appear to have come through the winter relatively well, although not as forward as we have become used to with the mild, wet winters of late.

Very pleasing this year is the level of residual herbicide control on blackgrass. It has certainly been a while since we have seen such high efficacy.

In addition, longevity has been good, with levels of control being seen all the way through the winter, particularly crops that received a flufenacet top-up.

The colder winter and frosty nights have aided the control. There is also the belief that the drier winter has helped keep the residuals in the top layer of the soil.

For crops that require a contact approach with iodosulfuron plus mesosulfuron, we are hoping for better control this spring, since the blackgrass is a much smaller target this year (one to three true leaves). This will also add a small amount of residual to the soil to help prevent further spring flushes.

The most prevalent disease is Septoria tritici and this will be the main focus of the first fungicide application. Chlorothalonil mixed with an azole – either tebuconazole or cyproconazole – will be the starting platform for the year.

Fertiliser plans

Attention turns to fertiliser plans, even though soil mineral nitrogen levels are slightly higher than we have been used to because of less winter leaching.

Despite this, we are looking to increase the first dose to encourage early tillering. This is particularly true of crops that struggled in the dry period in the autumn.

Winter oilseed rape will be receiving nitrogen and sulphur to enhance growth and help alleviate the pigeon damage as soon as conditions will allow travel.

Phoma levels remain low, but light leaf spot has been found in more susceptible varieties and will be the main focus once growth regulator and boron applications are required.

Spring cereal drilling will commence once field conditions allow. Areas where spring cropping is being used to control blackgrass will receive a flufenacet application containing mixes of diflufenican, pendimethalin and picolinafen, as well as high seed rates.

However, be mindful of diflufenican levels where winter rapeseed is to follow in the rotation.

South: Kevin Knight

Kevin KnightZantra (Kent)

Most winter crops have made it through in fair shape, though the rainfall lottery made poor oilseed rape establishment the norm across Kent and south Essex.

Subsequent flea beetle and slug damage exacerbated the issue and those who weren’t on top of pests in the autumn and pigeon control in recent weeks are now looking at spring cropping the failed ground.

The spring barley area looks to be up by 20% in Kent, either due to failed oilseed rape or as a result of needing to control blackgrass.

Given that this could suppress the barley market, some are considering spring rape, as it sits well within the original planned rotation.

Peas have performed poorly over the past couple of years, so are not as attractive, and the spring bean area seems fairly static across the South East.

The first split of fertiliser is going on in the next week or so – generally a sulphur-containing product.

Where cereals are thin, poorly tillered, or late drilled and backward, a little extra N has been applied (from 40kg up to 60kg or higher where needed).

The danger is heavy rain washing it away, but so far, so good. It should help the crop as temperatures rise. Following that, an early growth regulator will help with rooting and tillering and improve final ear count.

Foliar boost

Backward oilseed rape crops will get foliar P and K along with the first spring fungicide where needed. Disease levels have remained low in crops that received an autumn application of the SDHI-based Cypher (penthiopyrad + pyraclostrobin).

The cold spells have done a fair job of inhibiting rust sporulation in wheat, but there is certainly a lot more septoria than I would like to see.

T0 will be due on earlier-drilled wheats before the end of March and this will be based on azoles plus chlorothalonil.

While we are all mindful of input costs, this proves to be good value in keeping the crop clean until T1. Missing the T0 spray will require a more robust and very well-timed T1 to fight established disease, which will have already knocked yield potential.

Drills are rolling on lighter ground and early spuds are starting to go in. Let’s hope the fair weather lasts.

West: Giles Simpson

Pearce Seeds (Somerset)

Giles-Simpson

What a difference a year makes – crops on the whole look extremely well and full of potential. This time last year, winter barley was yellow and winter oats were purple.

Winter barley crops are receiving their first application of fertiliser to keep tiller numbers up. They will need a robust T0 fungicide, as they are full of brown rust and mildew.

Manganese will be added to the mix, with some crops showing signs of deficiency even though they received an application in the autumn.

There are big differences in the amount of disease present in winter wheat crops, with some early-sown varieties showing considerable septoria and mildew.

Crop being drilled in the spring

© Tim Scrivener

Lodging risk

A strong plant growth regulator and fungicide programme will have to be applied, as the crops are very forward and vigorous at the moment.

We, however, have to watch the fertiliser applications on these crops to manage crop canopy and stop them from lodging. Oilseed rape crops have been held back by pigeons and a cold easterly wind two weeks ago.

There has been plenty of disease in rapeseed crops and where possible, a fungicide has been applied. This has even been the case in crops that received a timely autumn application.

The autumn grass reseeds have wintered extremely well, but there is plenty of chickweed appearing in fields that haven’t been grazed by sheep. This will be a problem, so will have to be dealt with as soon as conditions allow.

Because of the general lack of rainfall, there has been quite a lot of slurry applied to grassland, both in the autumn and more recently. These applications will need to be accounted for in the fertiliser programme.

Spring cereal drilling has started on the better ground, with a lot of spring wheat being put in as well as spring barley.

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