Plenty of sun is forecast this week, which will help with grain fill in winter wheat crops.

The key issues being discussed by our agronomists this week include pests in pea and bean crops, managing weeds in very variable maize crops, and the rising potato blight risk in Northern Ireland.

See also: How Arable Insights farmers are using cover crops in rotation

North

Stephen Bell, Fane Valley (Northern Ireland)

Following a warm, dry May, normal service has resumed with June getting off to a much cooler and wetter start.

The much-needed rain was welcome across the country, especially on the lighter drier ground in the East, and came just in time for winter wheat as flag leaves were starting to roll up with drought stress. 

Unfortunately, the rain was just too late for many later drilled spring barley crops, and in general spring barley is a bit hit-and-miss depending on moisture after drilling.

Early drilled crops look to have good potential, with awns starting to emerge, while later sown crops are thin and struggling, having raced through their growth stages with flag leaves emerging on very short plants. 

Disease levels are low, but many later drilled crops are badly yellow tinged with signs of barley yellow dwarf virus.

Ear wash sprays targeting fusarium and topping up rust and septoria control have been applied to wheat during flowering.

Thankfully, yellow rust has been well controlled in varieties in the fungicide-treated plots at the trials farm.

However, there are marked differences in the untreated plots and clear indications of where the Yr15 resistance gene has been overcome in previously resistant varieties.

Keeping yellow rust out of crops from the get-go has never been more important.

Maize

Maize has got off to a good start with crops establishing well under film and in the open. Pre-emergence weed control has been variable, depending on site.

Post-emergence weed control is now under way, targeting grass and broad-leaved weeds as required.

Good control is easier to achieve on small, actively growing weeds and should be complete when maize is at the 4-6 leaf stage.

Maize plants use phosphorus very early in their growth. Phosphites can help encourage rooting and soil uptake, supplementing foliar nutrition to get crops off to the best possible start at a time when yield potential is being set.

Early potatoes have bulked well with good-sized tubers. Harvest is under way, dry matters are good and eating quality is excellent.

Despite dry conditions, weed control has been good and, with many maincrop varieties starting to touch along the rows, it is time to start the blight control programme.

An early start to blight control is key, protecting young susceptible leaves as they emerge.

With night temperatures into double figures and high relative humidity, blight pressure has steadily increased to high-risk conditions during the second week of June.

Growers are advised to ensure crops are protected using systemic chemistry applied at seven-day intervals during this period of rapid growth, and to follow a well-planned blight control programme mixing actives and alternating modes of action at each spray to protect the crop from blight until the haulm is dead.

East

Marion Self (on behalf of Harriet Bateman), Prime Agriculture/AICC (Norfolk, Cambs and Lincs)

The most commonly asked question to an agronomist as we move towards the second half of June is: “When do you think harvest will be and what do you think yields will be like?”

Not an easy one to answer, but thankfully things have improved a little as most people have had some useful rainfall in recent weeks and disease pressure is generally low across all crops.

Although cereal crops are generally thinner, and in some cases the drought has already done significant damage, the current lack of disease will allow those on stronger soils to make the most of the sunlight.

With a little more rain, things may not be as bad as we once feared, and, hopefully, there will be some quality.

For quality wheats, growers aiming for milling premium may be planning a final foliar nitrogen application at the watery to milky ripe stage.

To avoid scorching the crop it’s important to be careful to make these applications in cool, dull conditions. 

This season some wheats are carrying higher infestations of aphids in the ear than we have seen for some years.

In most cases treatment should be avoided as there is some resistance to pyrethroid in the aphid population and treatment is broad spectrum and will damage beneficial populations.

Continue to monitor crops, as populations will be affected by the weather. At the start of flowering the treatment threshold increases to two thirds of tillers infested. 

Pulse pests

In pulses, pea aphid and black bean aphid are at relatively high levels and populations will continue to build as temperatures rise. Again, applications should only be made when populations reach threshold.

For peas, treatment should be considered when 15% of plants are infested at early flowering. For beans, consider treating when 5-10% of plants are affected.

Remember to check product labels for the maximum number of applications per crop and harvest interval.

For instance, pirimicarb (such as Aphox) can be applied only once at maximum label dose of 280g/ha and has a seven-day harvest interval for vining peas.

Sugar beet establishment and weed control has been difficult this season; in many situations heavy herbicide mixes with tight intervals have been needed to gain control.

At last, even the more backwards beet crops are now covering the ground and beet will now respond well to plenty of foliar nutrition.

Take some time to look around the farm; assess and map variations in crop growth, weed populations and soil health so you can start planning how to address any issues.

Take time to visit shows and demonstrations and, most importantly, meet up with friends and fellow farmers. We are all facing similar challenges and its good to learn from each other and “chew the cud”.

South

Neil Harper, Agrii (Kent)

We discussed in May how the weather in the next six weeks would dictate the outcome of the season.

I’m delighted that our optimism has paid off, with just enough rain to support crops through to grain fill, and the current sunshine should finish this off nicely.

Our biggest challenge at present is the value of the crop in the field.

We have had to look after these crops to get them to where they are, but, for whatever reason, farmers aren’t being sufficiently rewarded for their hard work and investment. 

Oilseed rape and winter barley could well be the crops of the season.

However, both have thick canopies which hide a multitude of sins, and you never really know how well they have performed until the combine enters the field.

Before then, we will need to spray off oilseed rape as we head towards harvest.

Where a farmer has a trailed sprayer for oilseed rape, we’ll split the pod sealant and glyphosate applications, doing the pod stick sooner to fold the crop over in the tramlines.

The aim is to minimise potential losses when we go in later for desiccation.

The last of the T3 fungicides are being applied to winter wheat.

Wet conditions at flowering meant we stayed with prothioconazole as the base treatment and added tebuconazole or a strobilurin where we wanted additional rust protection.

Spring oats

We’re managing our biggest spring oat crop ever this spring, and the conditions seem to have ideally suited them. They get going quickly and do well scavenging for nutrients and moisture.

Farmers are primarily growing them for the low-input cereal SFI option, but they also fit well into the rotation, and we expect a similar area to be planted next year.

Agronomy for pulses this spring has been heavily focused on nutrition to support them through the dry conditions, and that emphasis seems to have paid off. 

Peas are looking good – better than I thought they would – although some crops have reached the threshold to treat for pea aphid, and we’re continuing to set traps for pea moth.

The first fungicides are going on and are based on azoxystrobin as a starting point.

Winter beans have looked good all season and are podding well. Spring beans had struggled; they came out of the ground and started flowering, although not very tall.

However, the rain helped them set pods well and gain some height.

And so ends my first spring as a Crop Watch columnist. I wish everyone a successful and safe harvest, with (hopefully) some better prices to show for all our efforts.

West

Ben Allard, Pearce Seeds (Dorset, Wilts and Somerset)

Winter wheats are marching their way towards harvest, with T3 applications being applied in between the showers and windy days in the West.

Winter wheat crops have now received a good drop of rain since my last article and, for the most part, are looking very good.

However, I’m afraid those on more vulnerable soils are still showing signs of the impact from the earlier drought, with time only able to tell the full extent of the damage.

T3 programmes have been based around a tebuconazole and prothioconazole mixture, to help top up disease control against rust and to provide protection against fusarium.

In a few untreated or lower input crops, I’ve seen signs of yellow rust and septoria starting to become more visible.

This gives me confidence that during the T1, and particularly the T2 timing, I made the right decision to stick with robust rates of chemistry and actives with improved stamina, helping to ensure clean crops all the way down through the canopy.

We are nearing the end of post-emergence weed control in maize, with only a few slower-germinating and later drilled crops still to be treated.

Maize crops across the West are very mixed, largely depending on soil type.

In areas where there was very limited moisture at the time of drilling, this has resulted in variable germination and establishment.

Some areas are now at the 3-4 true leaf stage, while in others even within the same row the maize has yet to emerge. This has certainly made post-emergence weed control more challenging.

Despite the lack of moisture, the weeds have established well, raising the dilemma: do you wait for all the maize to emerge, or tackle the ever-growing target and spray now?

My advice for weed control in maize is simple: go early (often at the first sign of weeds) and keep the rates up.

One certainty is that you will often be delayed by the weather, during which time the weeds will have doubled in size.

Where maize crops are strong and forward, attention is turning to foliar applications of nitrogen using urea polymer-based products such as Efficient28.

This can provide an additional 40kg N/ha to the crop and, over recent years, has delivered excellent results for me. 

As we approach harvest, I find this is a good time to reflect on the past 12 months. Like last year, it has been a relentless challenge, with many decisions dictated by the weather.

Now, as combines will soon to begin to enter the fields and we start to see the results of this harvest, it’s essential to stay positive, embrace each hardship as a learning opportunity, and look forward to the season ahead.