Crop Watch: Warm weather sees crops race through growth stages

A week of sunshine and warm weather has given crops a much-needed boost as they move rapidly through their growth stages.

As winter wheat flag leaves emerge, growers and agronomists are gearing up for T2 fungicide sprays.

We catch up with our Crop Watch agronomists to find out how things are faring in the field.

See also: Round-up of OSR varieties to drill in summer 2024

South

Alice Whitehead – Zantra (Essex/Kent)

We seem to have transitioned from winter to summer within a couple of weeks in the South East.

On a sunny day, wheat crops look gloriously green from a distance – but delve down below the crop canopy and the scars of dried-up septoria, rust and nitrogen scorch are easy to find.

Disease is still present in some crops and T2 fungicide treatments have been carefully thought out, with rates tailored to variety, location and disease susceptibility.

My active of choice has been Inatreq (fenpicoxamid), which offers very good protection against septoria, as well as good value to the grower.

Azoxystrobin and a triazole have been added as further tools in the battle against rust.

The new Adepidyn fungicide will feature in selected areas and varieties.  Hopefully, it will perform as well as it has in our trials. 

There are plenty of good-looking crops that are worth getting excited about. 

On the other hand, there are some crops on more difficult land that have hardly been touched since Christmas.

These are yellowing from rust and lack of nitrogen (or both). There are plenty of grassweeds about.

The most forward winter bean crops are flowering and have received their first fungicide.

I have opted for Elatus Era (benzovindiflupyr + prothioconazole) to protect against chocolate spot and rust.

Remember that most fungicide treatments on beans are protectants rather than eradicants – once disease has taken hold, it is usually too late.

Herbicides for broad-leaved weeds are being applied in combining peas – usually a mix of bentazone and MCPB to try to get more activity on difficult weeds.

Winter barley awns are emerging and it won’t be long before crops are out in ear. These will receive a final fungicide to keep the ear clean and minimise brackling.

There is not much left to do on oilseed rape now, other than keep an eye out for sclerotinia and any pod pests.

We recently had a weekend of rainfall, which saved on irrigation as potato planting came to a close. 

This moisture, combined with the warm weather, has finally pushed vegetable and salad crops into some rapid growth, hopefully bringing us out of the “hungry gap” in the coming weeks.

West

Gavin Burrough – Pearce Seeds (Dorset/Hampshire/Wiltshire)

A week of dry, warm weather is certainly making crops look a lot more pleasing to the eye. It has been busy in the fields and it’s great to see people catching up on a good amount of field work.  

Winter wheats are rapidly approaching T2 timing. Some earlier-drilled Extase have flag leaves fully emerged and other varieties won’t be far behind.

Spring wheats only just had their T1 fungicide. There is plenty of septoria in wheat and yellow rust has shown up on susceptible varieties where a T0 has not been applied.

Unfortunately, blackgrass is starting to appear. These areas will be noted and either hand-rogued or patch-treated with glyphosate.

Winter oats are now starting to go into stem extension and look a lot happier. Crown rust was easy to find, so they will have had a T1 fungicide – typically a tebuconazole and strobilurin mix with a growth regulator.

Winter barley should have had its T2 fungicide, along with manganese if growing on deficient soils.

As with everything, winter barley crops are a huge mixture, with taller crops receiving a late growth regulator of 2-chloroethylphosphonic acid and mepiquat chloride.

Other fields are being nursed to get to at least knee high, after being sat in waterlogged soil for a long time – or where barley yellow dwarf virus is a problem.

Straw values are high, so we are trying to find a balance between keeping the crops standing and not overregulating them.

Earlier-drilled spring barley crops are tillering. A lot did not get rolled immediately after drilling because the soil was too wet, so hopefully most fields can be rolled after a week of dry weather.

I normally try to complete any wild oat control with fenoxaprop-p-ethyl a week or two before the main broad-leaved weed herbicide is due.

However, an interval needs to be left after rolling, so that the crop is not stressed when next sprayed.

Maize drilling is now well under way – or will be as soon as the soil dries out enough and a good seed-bed can be made. Maize is very fussy so should not be rushed into a cloddy or compacted seed-bed.

Pre-emergence herbicides of either straight pendimethalin or a dimethenamid-p and pendimethalin mix are being applied if time allows, to make a start on the weed control programme.

North

Patrick Stephenson – AICC (Yorkshire)

At last, the sun has shone and caught out this fair-skinned person. The return to warmth has transformed the countryside as crops race through growth stages.

I must say I will be glad to see the back of this year’s oilseed rape crop. Don’t get me wrong, we have some good crops – but also, unfortunately, many poor ones that refuse to flower.

The catalogue of woes includes waterlogging, pigeons, flea beetle, and rape stem weevil.

Winter barley crops are wearing their hearts on their sleeves.

Where water logging has been an issue, they look very unhappy. The drier fields now look well, and ears are emerging.

The final fungicide is due on these and many will have an azole and strobilurin combination. This will be the last intervention before harvest.

Spring barleys are a complete mixture because drilling has taken place over a four-month period.

January-drilled crops now at first node will be due a first fungicide. The late-drilled crops are just emerging.

I try to manage brackling in spring barley by applying a later growth regulator. Although this does not solve the problem, it certainly delays the onset.

Winter beans are now flowering, and we are applying the first flowering spray – usually an azole and strobilurin. The beans are also a mixed bag but, on the whole, have survived winter well.

Spring beans are emerging and although I can find weevil damage it is not of concern. This could also be loosely translated as ‘we have nothing that works’.

If there are any broad-leaf weeds, you have a very limited window to use bentazone. Sadly, I have had limited success with this product.

Winter oats are now heading towards flag leaf and will be due a second fungicide shortly. At the risk of sounding like a stuck record, that will be based on a azole and strobilurin.

Winter wheat has certainly changed in the past 10 days but many crops are still better viewed from the road at 50mph.

Flag leaves are now emerging and T2 sprays will be due. As to what they will receive, it is a complete mish-mash of products.

I completely understand why twin packs are supplied to comply with registration issues, but do we have to have so many?

I am sure Pythagoras didn’t have to do as many calculations as us agronomists – working out the best-value combinations.

Add to this the arrival of Adepidyn and the choice is limitless. One thing is certain: I will not skimp on T2 in terms of efficacy and the new chemistries will be applied across the board.

Two weeks ago, I would have said late growth regulators were a pipe dream – but, with a massive surge in growth and Dawsum and Champion in many fields, these are now planned.

East

Ryan Baker – Frontier (Suffolk/Norfolk)

The beginning of May finally brought some warmth and crops have now started to motor through their growth stages.

Winter barley has recovered from catchy weather in April, allowing T2s to be applied as the awns emerged.

However, drilling dates from February to May have had a large influence on spring barley development.

Only early crops have received their T1s and later crops are only just reaching the end of tillering.

If conditions remain dry and later-drilled fields struggle, this could be a good opportunity to trial biostimulants on farm.

The cooler conditions earlier in the season seem to have had a negative impact on the control of groundsel.

The weed has waxed quickly and sulfonylurea herbicides have struggled. In response, the industry is taking note of what is increasingly becoming a problem weed on many farms.

If resistance is suspected, collect seed and test it to help inform decision-making for 2024-25. Interestingly, autumn-applied metribuzin has reduced pressure from the weed.

The middle of May brings the approach of the crucial flag-leaf timing in winter wheat.

However, there is still variability in crops based on drilling date and this requires the matching of programmes to the yield potential and disease risk.

Accurate timing in variable crops remains a challenge. Following on from the launch of Vimoy (isoflucypram), the recent registration of Adepidyn will provide greater options for T2.

It is a fantastic active for septoria control but needs support on rusts. T1s have dried-up yellow rust successfully but brown rust is found on susceptible varieties.

Warmer soil temperatures mean that maize drilling is progressing apace. Adequate soil moisture means that a residual herbicide will reduce weed burden as the crop emerges.

Peas and beans emerged well once night-time temperatures rose, with little damage from pea and bean weevil.

Vining peas have also provided a good opportunity for blackgrass control in problem fields.

Sugar beet emergence has been slowed by the cooler April. Both hail and slugs have caused damage to cotyledons but once temperatures climbed and the first true leaves emerged, the beet recovered well.

Bindweed and brassicas seem the most prevalent weeds so far and first herbicides have been written up with these in mind.

Winged aphids have been easy to find and colonies will soon become established as the weather becomes more settled.

Insyst (acetamiprid) as a third insecticide has now been approved as an emergency authorisation.