Warmer weather is giving crops a welcome growth burst, but with it creates the perfect conditions for populations of weeds, pest and disease to take hold.

Timely spray applications will be critical to keep these in check.

Farmers Weekly finds out the latest advise from our regional Crop Watch agronomists.

See also: Growers advised to stay vigilant for brown rust

South

Tod Hunnisett
AICC (Sussex)

May is traditionally the month when agronomists’ other halves look up the numbers for local relationship counsellors, and search for courses on “How to be extremely patient with non-sleeping partners”.

For some reason, speaking personally, this May doesn’t appear to have been quite as manic.

Early drilled winter wheat crops shot away early, but then were held back by the cold (but not freezing) northerly wind, and later drilled crops appear to be catching up now the weather has warmed up and hasn’t yet turned ridiculously hot.

Regular rainfall events have made field operations challenging, but the ground dried up quickly afterwards, and once again, the operators who have snatched opportunities are those who will come out on top.

Having said that, 75mm of rain over 24 hours in parts of Dorset and Isle of Wight last week did test a few people’s sanity.

As I write, there is wheat in ear now in Kent, but that has been normal for the last few years.

By the time this goes to press most wheats will be showing ears, some between the blackgrass heads on crops that didn’t get an autumn pre-emergence herbicide. 

Alopecurus myosuroides (blackgrass) will still be around even after some despotic dictator has pressed the red button and all other life has disappeared.

I’m confident that the vast majority of winter cereals will be flowering by 10 June, regardless of when they were sown, as they are every year. Isn’t nature wonderful when it works for us?

Oilseed rape has once again astounded me with its ability to compensate and push out buds and pods in areas that looked dire a month ago.

What it will do for overall yield is uncertain but it must add something. It simply reminds me that most plants are the opposite to sheep – all they want to do is survive.

West

Antony Wade
Hillhampton Technical Services (Hereford/Shropshire)

Well, the weather gods have started to show a kinder side with some periods of settled weather, but with still enough rain showers to not dry out spring crop seed-beds too much.

Spring crops have emerged well despite the later sowing dates. They are growing fast and starting to tiller.

The good growing conditions have caused a flush of broad-leaved weeds to emerge, so herbicides will be the first action on many spring crops.

Wheat flag leaf sprays will mostly be complete. Fortunately, a dry spell of weather has allowed them to be applied to emerged flag leaves.

Septoria is at high levels on leaves four and five across all varieties in my area, and even Extase and Palladium have significant infection on lower leaves.

As a result, most crops will get a robust rate of fenpicoxamid, with earlier sown crops receiving at least 1.25 litres/ha.

A few good crops with decent potential will get the new recently approved Adepidyn (pydiflumetofen) from Syngenta.

The patchy crops that looked poor in early spring have improved, but most crops are below optimum tiller numbers as a consequence of the wet spring and the delay in getting early nitrogen applied.

There have been reports of yellow and brown rust in other areas of the country, but I am only finding yellow rust in November and January drilled crops.

This is regardless of varietal resistance, so is purely a result of sowing date.

Grassweed control from contact herbicides was disappointing, but with the delay until mid-April for many applications due to the wet weather, it is unsurprising control has been compromised.

Oats are growing rapidly so final splits of plant growth regulators are being applied at the same time as Wheat T2’s.

Disease has been well controlled by T1 applications, but the occasional pustule of crown rust can be found.

Final fungicide applications will be applied, with some coverage on the panicles as crown rust can come in late and affect grain filling.

Winter barley crops are in ear and looking at their most pleasing, but late season disease such as ramularia can still come in.

Maize crops have gone into good seed-beds and pre-emergence herbicides have been applied with the prospect of weed control as there is adequate soil moisture available, but it is too early to assess.

The long-awaited improvement in the weather and equally awaited rise in wheat and oilseed rape prices has helped instil some optimism that the 2024 season will be one to forgive, rather than to forget.

East

Marion Self
AICC/Prime Agriculture (Suffolk)

Hoorah for the spray operators who are juggling their daily workloads to carefully apply complicated mixes to a combination of fast growing, tender crops.

It’s one thing sending recommendations, quite another getting all that work done.

The changeable weather has allowed some good spray days interspersed with wet ones, which have washed in final nitrogen applications.

This and warmer temperatures are encouraging fast growth, along with weeds, pests and diseases.

Timely applications in these conditions are critical. Earlier wheats drilled in challenging conditions and those drilled late now look well, although yield potential still remains highly dependent on weather conditions from now until maturity.

Wheat flag leaf sprays (T2) are under way, with later drilled crops now approaching flag leaf emergence. The timing between T1 and T2 fungicides has been kept tight to protect the upper leaves of the canopy from disease. 

Severity of infection is very much related to drill date this year.

Showers and warm weather have driven septoria development, which is often high in September and October drilled varieties with a Recommended List rating of 6.5 and below.

Mid-October and later drilled crops are significantly cleaner for septoria, but susceptible varieties have rust and mildew, particularly where stressed and/or higher seed rates have created a humid microclimate in the canopy base. 

Correct application is key to good efficacy – pay particular attention to spray quality, forward speed and boom height, as well as using robust water volumes to penetrate the canopy.

Septoria is the key target at T2, but where varieties have a rust weakness, the mix should include additional triazole or strobilurin actives to support the strong T2 septoria targeting fungicides.

Spring cereals are racing through their growth stages so be careful not to miss opportunities to apply planned treatments.

In contrast to last year, the few winter bean crops are not particularly thick. Nevertheless, continued disease protection for chocolate spot and rusts during flowering is important, especially in wet and warm conditions.

Good plant health and foliar nutrition are also required to help the plant resist disease.

Spring beans have established well and look promising – make sure you complete grass and broad-leaved weed control early before label restrictions prevent their use.

Sugar beet has also established well and is growing fast, but weeds are growing just as quickly. There are a lot of weed control treatments to juggle, especially if this is happening alongside aphid control in non-Cruiser SB treated crops.

Aphids that transmit viruses such as the wingless Myzus persicae (aphid) have arrived in beet.

Their numbers are increasing, and when the economic threshold is reached in non-Cruiser treated crops, treatment with an approved foliar insecticide will be required.

As a reminder, the threshold for aphid control is one green wingless aphid for every four plants, up to the 12-leaf stage.

It is also helpful to visit the BBRO site to view any aphid trap catches near you: bbro.co.uk/on-farm/aphid-survey-map.

North

Conor Campbell
Hutchinsons (Northumberland)

At long last the weather has settled, and progress has been made.

It is amazing how some good weather and the countryside starting to green up improves your mood and outlook. Stronger prices might also be helping).

There has been a huge amount of work achieved in the last 2-3 weeks, with spring crops now in the ground and looking well.

Generally, at this time of year, we start to tick crops off the list and the spraying reduces. However, with the large area of spring crops in the ground, I can see our busy period running on much longer than normal.

I think I have 10 different crops on one farm this year, which should keep me out of trouble.

With the large variation in wheat crops, I have tried hard to adopt a flexible approach and treat each on their merits, but also not expose their potential to disease.

We have some wet weather forecast still, which, while welcome, will increase septoria risk at T2. We’ve had several sea frets along the east coast which will increase yellow rust pressure.

The better crops will see newer chemistry, while the poorer crops will still need protection, but from older actives to manage spend.

I’m fortunate that we have a huge range and can adapt to the crop condition in front of us. This is the year for getting crops to harvest as best we can.

Oilseed rapes and winter barleys are all but finished with until harvest. The barleys don’t look too bad considering they aren’t known for their ability to handle wet and poor conditions.

Some of these new two-row varieties look to have potential.

There is a lot riding on the spring crops this year, and they are off to a great start. Typically, they are sown into less-than-ideal conditions, but not this time.

Some warmth and plenty of moisture means they’ve come through the ground well.

Next on the to-do list will be weed control and nutrition to keep up the momentum.

Often, spring crops are thought of as the poor relation, but if pushed and managed well they can return some very impressive yields.

I would encourage anyone who is looking for straw and feed to not hold back, especially if we do get some rain to keep moisture levels topped up.