Crop Watch: Wet weather ruins cropping and herbicide plans

In our final Crop Watch installment of 2023, our agronomists reflect on what has been a grim autumn disrupting drilling and herbicide applications to wheat. 

With wheat drilling unlikely to resume in some areas, thoughts are turning to the choice of spring cropping, although seed availability may be a deciding factor.

This combined with nursing wheat crops with patchy emergence and missed herbicide applications means there are going to be some tough decisions next spring.

See also: How biologicals and new approaches are changing pesticide use

South

Alice Whitehead

Zantra (Essex/Kent)

Well, that escalated quickly. Last time I wrote, I welcomed a moderate amount of rain to assist with residual herbicide activity. 

Since then, it seems to have rained non-stop, with east Kent appearing to have suffered the most in this corner of the UK.

South Essex has received less, although on the heavy clay soils it does take longer for the ground to dry to allow spraying to recommence. 

Some growers would like to drill more wheat if they get the chance, although it is looking less likely in some areas and the topic of conversation is already switching to the choice of spring cropping, with spring barley and spring oats the favoured options.

Generally, cereal crops are looking well where they were established in good seed-beds, and thankfully the rain and pre-emergence herbicides combined have not appeared to have caused too much yellowing. 

However, in some cases the rain came before seed-beds could be rolled and pre-emergence herbicides applied and these areas are left in a bit of a mess, with most of these fields untouchable at the moment as they are sitting so wet. 

Slug-grazed leaves are easy to find, although only the odd field has been bad enough to require pelleting.

Fortunate growers

The more fortunate growers have applied treatments for barley yellow dwarf virus and top-up herbicides for grassweeds where required.

I have avoided any contact grassweed applications, mainly due to the catchy weather, which is not ideal for successful applications of products such as Atlantis (iodosulfuron + mesosulfuron) or Broadway Star (florasulam + pyroxsulam). 

Instead, I have opted for more residual herbicides, using different actives to the pre-emergence mix, although flufenacet has featured in both applications.

Some growers have given up trying to get winter beans in now, but most are still holding out for a few consecutive dry days.

Oilseed rape crops are mostly shut up for winter, with soils finally cool enough for propyzamide applications in the past week or so.

I am pleased with crop canopies going into winter, which amazes me after the worry we had with high temperatures and lack of moisture in the early stages of leaf development.

Hopefully, crops will withstand pigeon pressure over the next few months. 

I am not finding much flea beetle larvae in stems or petioles so there is every reason to be hopeful of a good crop, although there is a long way to go yet.

North

Patrick Stephenson

AICC (Yorkshire)

What is a Crop Watch without mentioning the weather? And on the meteorological front, autumn has been grim. Rainfall of 175mm is common across the region in the past five weeks.

The consequence of this is the tell-tale signs of glistening fields. Beneath the glisten establishment of the later drilled fields is variable, and a combination of slugs and water have provided a checkerboard appearance.

We are fortunate that we start to drill early, always fearing that this current weather pattern will strike.

For many there will be no further land work until the new year. However, in contrast, the soils at the lighter end will still be able to continue with some land work given a small window in the weather.

Manganese is always a threat to cereals on the prone soils and I firmly believe that getting a spray on this side of Christmas is vital.

Aphid numbers have dropped considerably, and October sowings will be very low risk for BYDV.

Pre-emergence herbicide programmes have worked very well and although the plan was to top these up with some more residual, conditions have meant that this has now been abandoned.

My rapidly diminishing area of oilseed rape is manfully limping through the winter and propyzamide applications are a priority.

I can find flea beetle larvae quite easily, but this currently is confined to leaf petioles.

Phoma has been treated where early lesions were found, and no further treatment is planned.

Having spent several years traveling down the East Coast railway line, I have seen the changing countryside with eager anticipation.

This year I must admit that the closer you get to London, the better the rapeseed crops look. Sadly, this year Yorkshire is the much poorer cousin.

Yellow barley

Winter barley crops have started to take up their usual winter colours of pale yellow.

This bleaching is a combination of pre-emergence herbicides and excess water. Looking at them is best done at 55mph from the road.

Slugs have thrived in the wet conditions and controlling damage in direct-drilling situations or regen fields has been more than a challenge.

Once again, wet weather does not help keeping slugs underground and destroying the pellets above ground.

Most of the planned drilling has happened, and although some remedial work maybe required, I think we are in a better position than many.

Volunteer beans are an issue in some crops, and although florasulam, or tribenuron, offer cost-effective solutions, I think control will have to wait until the spring.

Many have planted winter beans, and spraying pre-emergence herbicides has been another challenge – I fear some difficult discussions will be had.

I don’t like sowing winter beans past the end of the month as I worry the later harvest and lower yield potential are challenging.

Because of the weather, planning for spring is already in full swing, and with all spring seed being at a premium, we must assess the options.

In my part of the world, continuing to drill wheat is an option through to March. The caveat to this must be patience and conditions.

As Corporal Jones would say: “Don’t panic, don’t panic!”

East

Ryan Baker

Frontier (Suffolk/Norfolk)

Unfortunately, after suggesting last month that regular rainfall was assisting with the creation of stale seed-beds, rainfall has not stopped.

With two named storms and total autumn rainfall now exceeding 200mm, land is well and truly waterlogged.

This has shown up clear differences between poorly structured land and the well-structured land where the water is able to drain sufficiently back to field capacity.

Regrettably, some poorly structured fields and headlands have resulted in seed rotting in the field.

Chances of drilling further wheat on already cultivated land is decreasing.

Sugar beet harvesting is providing some slightly drier conditions to allow drilling to continue.

In these circumstances, increasing seed rates and choosing varieties such as Skyfall, Champion, Redwald and Cranium, with a lower vernalisation requirement and higher late-drilled yields, become more important.

Slugs are still very prevalent and monitoring in slower emerging crops will be critical while temperatures are mild.

Where pre-emergence herbicides have been applied in a timely fashion, blackgrass control has been very good. Cinmethylin has once again been the stand-out active.

OSR weeds

Belkar (halauxifen + picloram) applied earlier in the autumn has done a very pleasing job. We certainly have the soil moisture for application of propyzamide, but we are currently still 2-3C above the 10C soil temperature and falling requirement for the best efficacy.

Earlier drilled crops with the largest canopies can be left until colder weather has opened up the canopy for better coverage.

This is especially important if using aminopyralid for poppy, mayweed and groundsel.

Many will take this opportunity to apply an autumn fungicide for phoma and light leaf spot control.

Very few winter bean crops have yet been established. Later drilling of beans is achievable, but they will not enjoy cold and waterlogged soils. If broadcasting and ploughing beans closer to Christmas, field losses will be higher.

Winter beans can be sown in the early spring, but should be treated as spring beans. Aim to establish 36-40 plants/sq m in this scenario.

Despite a later sugar beet drilling season, reported sugars have been averaging 16% with yields approaching 80-100t/ha.

Where only one fungicide has been applied, beet is now showing significant levels of rust and cercospora.

This poses the risk of defoliation of the crop, increasing the likelihood of frost damage to later lifted beet in the case of a harsh winter.

West

Gavin Burrough

Pearce Seeds (Dorset/Hants/Wilts)

It is no surprise that very little field work has been completed since my last article.

Looking at the forecast for our local area for the coming week, the weather does look to be improving with temperatures slowing reducing. I can only hope this is accurate and some field work can take place again.

However, it only takes a small amount of rain before the ground is saturated again and we are back to square one. 

Phoma is appearing in oilseed rape crops, which is no surprise given the weather we’ve had. A fungicide will be planned for the next time there is an opportunity to spray, along with some boron foliar feed if required.

Kerb (propyzamide) or Astrokerb (aminopyralid + propyzamide) will be planned for when soil conditions are cool enough, at or below 10C at 30cm depth.

Very few cereal fields have had a post-emergence herbicide or aphicide applied. What little that has been applied has been restricted to a few free-draining soils over chalk.

This is causing concern, especially on fields with high grassweed pressure.

Wheat drilling

A small amount of wheat drilling has taken place on some light, sandy ground.

With the heavy rainfall events that seem to keep happening on a weekly basis, hopefully, these later drilled seed-beds on light soils will not cap.

Where there is still wheat to drill, seed rates will be increased if the opportunity to drill still occurs.

Latest safe drilling date of winter wheat is being considered when juggling the decision of whether to drill or keep the seed in the bag and swap to spring cropping.

The decision is being made more difficult due to the potential lack to spring cereal seed.  

Winter linseed is growing slowly. The crop will receive an application of difenoconazole for disease control when conditions allow by the end of November if it hasn’t been done already.

Attention/conversions on rainy days have turned to the new Sustainable Farming Incentive options, especially on wetter ground to help reduce financial risk with the ever-reducing Basic Payment Scheme payments.

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