Crop Watch: Decision time looms for T2 spray selection

“Can I save on my T2?” is the question that has been ringing in the ears of our Crop Watch agronomists this week, as the time for the second fungicide spray in cereals fast approaches.

Patrick Stephenson’s response is that there is likely only room for minor tweaks, rather than major savings, with only T1.5 users really having the opportunity to be more rate appropriate, he believes.

Marcus Mann’s advice is to consider the yield potential in light of the recent dry weather, with some crops on light land reducing nodes and tillers, although using an SDHI will help retain green leaf, he notes.

See also: Video: Four mechanical weeders put through their paces

Over in the West, Giles Simpson advises adding a strobilurin into the mix for varieties which have a low resistance rating to rust.

If mildew is bubbling away in the base of a stressed crop, Kevin Knight says adding a cyflufenamid or proquinazid and upping the water volume will give the best results.

West: Giles Simpson

Pearce Seeds (Somerset)


Giles Simpson

As I write this we have just had 10mm of rain overnight, and boy did we need it.

The spring crops had been under severe stress through lack of moisture and although we haven’t had high temperatures, the cold north-easterly wind has been sapping any moisture out of the ground.

Hopefully this will save the crops. The spring barley that had been drilled early has got away and looks good, but the late-drilled crops were struggling to germinate in some areas.

The split germination across fields will make spraying interesting in the coming weeks as there will be a huge difference in growth stages across some fields.

The winter oilseed rape has had a very long flowering period, and pod development looks good, so hopefully this crop can now fulfil its full potential. These crops have now had their final nitrogen and late flowering fungicide.

The winter wheats are now receiving their T2 fungicide. In most cases, where the timings of T0 and T1 have been good, these crops look clean.

This is not the case if T0 was missed or the timings have been incorrect; the wind had slowed the sprayers down at times.

T2 will be an SDHI and triazole mix but where varieties have low rust ratings, a strobilurin will be added.

Hybrid winter barley competitive

The winter barley has ears fully out now and has received its last fungicide. These crops look the best of all; the hybrids again have coped with the drought stress better than the conventional.

I can see the hectarage of hybrids increasing again this year, so make sure you book your seed if you haven’t already.

The early-drilled maize crops have taken three to four weeks to come up, while later drilled crops have taken 10-14 days and have caught up the early crops.

Thankfully most of my customers waited until soil temperatures were settled at 10C and rising.

Some crops have had pre-emergence spray applied after a lot of discussion as to whether there was enough moisture.

I still think this has been the right thing to do, although I’m sure I will have some customers who will take much pleasure in discussing this in a few weeks. Hopefully there will be a few sprayer misses to help me win the discussion.

East: Marcus Mann

Frontier (Essex)


Marcus Mann

Prolonged dry weather has caused spring crop emergence to become inhibited, particularly where seed-beds have not been consolidated enough to hold the moisture.

Winter crops at present still remain surprisingly well, particularly the first wheats behind pulses and winter oilseed rape, which had begun growth early through the winter months due to higher soil N levels.

Unfortunately on lighter land this has already begun to lose its potential, with crops shutting down reducing nodes and tillers.

With T2’s being applied to forward varieties such as Skyfall and Siskin, decisions have to be made based on the crop’s current potential.

A strong triazole mixed with a strobilurin and chlorothalonil is an option. However there is still merit in these conditions to continue with the planned SDHI.

Trial work in 2011 (a dry year) certainly supported this with increased yields through the improved water use efficiency and green leaf retention.

Regarding disease pressure, septoria and yellow rust are present in crops and if the weather were to turn wetter this would inevitably begin creeping up the leaves.

Check the ADHB resistance scoring data – varieties such as Reflection must have an emphasis on rust control and adding a strobilurin can help add further control.

If growing a variety of milling wheat consider using chemistry containing prothioconazole for added fusarium control.

Sclerotinia decision time

Winter oilseed rape has had a prolonged flowering period this year and timings of sclerotinia programmes have been monitored.

If the crop is still flowering and the fungicide has reached a three-week interval, a decision based on sclerotinia pressure must be taken.

It is also advisable this year to take leaf tissue samples to assess levels of nitrogen within the crop.

A dry period when earlier fertiliser was applied could have restricted uptake efficiency. If levels look low at petal fall it is the time to apply a liquid foliar feed to supply a further 40kgN/ha directly to the pods.

Spring cereals are in urgent need of rainfall. All nitrogen is applied. However nutrients such as manganese, copper and magnesium will be added to fungicides to help boost a crop where it’s struggling to find the necessary micronutrients in the dry soil.

Also be aware of migrating aphids as they will still be BYDV vectors.

South: Kevin Knight

Zantra (Kent)

Kevin Knight

Kevin Knight

Despite the odd shower, the South-East is beginning to switch to damage limitation mode.

On light soils, chalk downs and in second wheats, the winter cereals seem to have decided to set seed asap before they run out of what little steam is left in them.

Crops are coping better with the drought stress on soils with higher organic matter, and where P and K indices are two or over.

This increase in resilience to the impact of weather extremes is a key benefit of improving the carbon content of your soil, and maintaining sensible nutrient reserves.

Drought stress has made spray overlaps obvious in terms of crop effects from graminicides and plant growth regulators.

Dry weather obliterates spring weeds

On a more positive note it has resulted in some of the best spring weed control I’ve seen for a long time with blackgrass, ryegrass and even onion couch taken out to good effect.

Tissue tests of first wheats that have been amply fertilised have shown deficiencies in nitrogen, sulphur, magnesium, zinc and boron.

Dry soils have prevented uptake of what is available for weeks. A readily available foliar feed containing the elements required can go some way to alleviating stress and disease symptoms.

Flag leaf emergence on early drilled/first wheats is usually around 21 May here; this year T2 will be done on all bar the most backward second wheats by then.

T2 plans have been under constant review, but on crops with potential an SDHI + azole + chlorothalonil mix is being applied.

Where yellow rust is an issue then rates of chlorothalonil have been reduced and a strobilurin added.

Brown rust is just starting to appear on untreated trial plots, with the odd spot in spray misses on farm, which will influence T2 rates on susceptible varieties such as Crusoe.

Mildew is bubbling away in the base of stressed wheat. Hitting the mycelium is difficult where crops are thick but if water rates are kept up, better penetration of the canopy can see good results from the addition of cyflufenamid or proquinazid.

Crown rust appeared last week in winter oats, as has mildew, both checked by tebuconazole + azoxystrobin + cyflufenamid.

North: Patrick Stephenson

AICC (Yorkshire)

Patrick Stephenson

Patrick Stephenson

I have never had so many different T1 combinations in wheat crops as this year. It is quite ironic that the late-drilled wheats have just received their T1 sprays and the early-drilled crops are nearly ready for the T2.

I have recommended a reasonable amount of T1.5 sprays to ensure disease protection through to flag leaf fully emerged.

The topic of conversation with my clients seldom strays from the impact of the weather on crops. The main question is: “Can I save on my T2?”

Unfortunately, the purpose of this spray is not only to maintain what we have, but also protect from what we might lose. From flag leaf fully emerged to the end of grain fill will be approximately 70 days.

There is very little scope for major savings, only for fine tweaking, and I am looking at cost-effective SDHI alternative products as the best way to optimise the spend and maximise profit.

Where a T1.5 has been used there may be scope to be more rate appropriate. Yellow rust has been bubbling away in the background and the new races are very aggressive, often cycling from spore to new infection in less than a fortnight.

Wheat variety choice for the coming year will have to try and account for this rapidly changing situation.

Gate closed on oilseed rape

Oilseed rape has finished flowering and for the vast majority of crops, it has been a one-spray season.

Seed weevil has been noticeable by its absence, helping us to limit the broad-acre use of prophylactic pyretheroids, which must be good for all involved.

Pod set has been very good and yield potential looks promising. I hope that this translates into good yields and we will be able to forget last year’s miserable effort.

Winter beans are flowering now, but with no chocolate spot we are delaying our first fungicide until the weather changes.

Spring beans are on the whole looking good, with very little weevil damage. Unfortunately, the pre-emergence herbicides have struggled and we are left to do battle with the bentazone products.

I would love to have confidence in them working but they are at best variable. My standard comment is: “You will have more success in using the empty can as a hammer to kill the weeds.”


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