It’s been a postcode lottery for rain with the South West having had a good wetting while other areas like the East are still dry. 

For weed control, it means pre-emergence herbicides have had limited effect in some spring crops like barley, beet and pulses.

How to tackle these weeds along with T2 spray options in winter barley are among the topics covered this week by the Crop Watch agronomists.

East

Ryan Baker, Frontier, Suffolk/Norfolk

After a welcome dose of rain earlier in the month, there is now limited rain in the forecast again.

However, most parts of my area did receive a sensible amount, enough to wash in any applied nitrogen and germinate remaining spring crops.

The lack of rain has provided ample opportunity to apply T1s to winter wheat in a timely fashion.

This is reassuring as it has been easy to find yellow rust in unexpected varieties.

This has included Dawsum, Champion and Typhoon, which previously had shown seedling resistance.

Thoughts have now turned to growth regulation and T2s on winter barley.

Fully emerged flag leaves were easy to find in the most forward crops from the third week of April.

Many crops have been variable all season. Hybrids and the lushest conventional varieties will justify a flag leaf plant growth regulator.

After success on a limited number of farms last year, pydiflumetofen (Adepidyn) will feature strongly due to its efficacy.

Rust is the weakness of many hybrid varieties and should be factored into the fungicide programme.

Spring barley

Spring barley was established much earlier this spring compared with last.

Where drilled into moisture, it has established evenly. Slightly later drillings and headlands have struggled.

Crop stress brought about by the dry spring has given the opportunity to trial Status (MTU + pidolic acid) in order to improve resilience and nitrogen use efficiency.

Pre-emergence herbicides have had limited success and this has increased the importance of the correct herbicide actives at T1.

Peas have also established well, but the dry conditions have again limited the efficacy of some pre-emergence herbicides.

Bentazone + MCPB can be a useful option for tidying up weed control. Bentazone alone can also be used in spring beans, especially against weeds such as charlock.

The end of April brought the first reports of aphids in sugar beet crops.

At the time of writing, I have not found any colonies at threshold.

Weed control has been relatively straight forward in crops that emerged evenly.

However, later drilled crops and those on heavier land with uneven emergence have proved challenging.

Weeds have very quickly put out a true leaf where beet ranges from unemerged to four true leaves.

The kindest mixes will be based upon phenmedipham, ethofumesate and metamitron.

Oil is going to be required to target larger weeds as soon as the crop will allow.

Care should be taken with fluctuating temperatures and oil rate.

North

Mary Munro, Munro Agricultural Consultancy, East Lothian

The dry weather continues, disease levels are low, and jobs are up to date.

In my area the mad week is the first week in May, so I reckon we are a week ahead of normal.

Flag leaf sprays for winter barley are now on or imminent – Revystar (fluxapyroxad + mefentrifluconazole) plus prothioconazole and Terpal (ethephon + mepiquat).

These crops are very clean and no doubt there will be growers taking a chance with lower input options.

Harvest is a long way off, and I would prefer not to have to go back into the barleys with a third fungicide.

There is also the likelihood of some rain between now and then.

We had a few days of gentle showers which was enough to wash in fertiliser, and ideal timing for the spring crops to get a decent bit of moisture as they came through the ground.

The spring barleys are now tillering vigorously and are spotlessly clean, and the rain brought a flush of weeds as well.

I am glad of this, as the last time we had a very dry spring there was a massive wave of late germinating weeds that caused a lot of headaches.

Manganese is a routine treatment at this time for most of my growers.

Septoria

Winter wheats are spectacularly free of septoria.

There is some showing up in certain varieties, but the pressure is very low.

We don’t seem to be having the yellow rust problems of further south, and mildew has not posed a big threat.

Having done some arithmetic and risk assessment I have plumped for Revystar plus tebuconazole and the remaining chlormequat for most T1s.

I have played with the rates depending on site and variety, but they are all lower than last year.

While disease has not been a major challenge, there are a few pests to deal with.

Uneven and slightly disappointing development of a wheat crop prompted further investigation and the discovery of a mix of cereal cyst nematodes and free-living nematodes. I suspect these are more prevalent than people realise.

We have a lot more aphids than usual and they are at all stages of development including wingless family groups on the leaves.

I am monitoring them in case they cross my tolerance threshold.

The oilseed rape crops are in full flower and Aviator (bixafen + prothioconazole) was the product of choice for their one and only fungicide treatment.

I love a dry spring.

West

Dominic Edmond, Matford Arable, Devon/Cornwall

After a March of virtually no rain, the beginning of April started with little prospect of any on its way, but as the month progressed and after constantly checking weather apps to find the forecast you liked, rain eventually arrived.

Good rain, generally. Some areas of Devon and Cornwall received up to 90mm.

For many crops, this was hugely welcome, and with fertiliser applications kicking in, crops have started to move.

Most winter barley crops have received their T1 fungicide application, and after holding my nerve, also a robust growth regulator programme.

Disease levels are acceptable, but rynchosporium is lurking about in some.

T2 fungicide applications aren’t far away as barleys approach awns tipping stage – with many starting to look quite promising.

Winter wheat crops have been getting T1 programmes applied of late. The rain coincided with this timing, and some are being applied late enough with leaf three well out.

You don’t have to look far for disease in the bottom of earlier drilled crops, and with septoria being the number one enemy in the South West using the best fungicide available at robust rates is important.

Spring crops

Many of the earlier drilled spring barley crops have now emerged and are tillering, with some T1 programmes pending.

Others will need walking over the next week or so.

With warm conditions forecast they will start jumping forward along with plenty of weeds.

Pre-emergence herbicides have worked well, where used in spring barley and eased early weed pressure.

While some maize was planted pre-Easter, most is getting drilled now and over the next few weeks.

Perfect conditions really, with plenty of soil moisture and rising temperatures, maize shouldn’t take long to emerge.

Nearly all my acreage will have a pre-emergence herbicide, which allows the maize to grow away competition free, knocks out some of the more problematic weeds for post emergence control, and also insures against the weather getting wet around the three- to four-leaf stage of the crop and preventing travelling through the crop to tackle weeds.

Most will get some form of post-emergence weed control, but can be more targeted.

With the forecast set fair, crops are setting themselves up nicely and with good windows for input applications there are reasons to be cautiously optimistic.

South

Justin Smith, Procam, East Sussex

Maize establishment is ongoing with the earliest crops already emerging.

Pendimethalin is, therefore, being applied where weed burdens are highest.

Adequate soil moisture – thanks to some much-needed rain – is helping weeds to chit quickly, so fingers crossed for some effective broad-leaved weed suppression.

The recent damp weather has also helped spring barley and oats to move forwards at pace, with manganese, rooting enhancers and stem strengtheners in the form of trinexapac-ethyl and prohexadione being applied.

Despite some rain, conditions have largely remained dry, so I wanted to make sure crops have a healthy root mass and wall strength to avoid the threat of weak straw if, and when, crops bolt through their growth stages.

As a wise colleague once said, “you cannot regulate growth that’s already happened”.

Winter barley

Winter barley is already shooting ahead, with some crops already at growth stage 49.

Even though crops were struggling to get off the floor three weeks ago, it has been pleasing to see that growth regulators were applied early in many places with crops not looking too tall or weak.

Most winter wheats are now at growth stage 32, with T1 fungicides being applied with growth regulators where required.

The robust T0 fungicide treatments that most crops received have successfully held septoria and rust at bay on the usual suspect varieties.

However, despite the lack of rain, septoria seems to be rising quickly in thicker crops.

In this scenario, and for those with a compatible sprayer, my T1 fungicide recommendation has been Inconiq (fenpicoxamid) plus Clayton Finch (tebuconazole + prothioconazole).

Where septoria levels are lower but the risk of rust is greater I have opted for Vimoy (isoflucypram) plus Cello (spiroxamine + prothioconazole + tebuoncazole).

And in backward and potentially lower yielding scenarios, I have opted for a cheaper mix of Bugle (fluxapyroxad) plus Clayton Finch.

Like many, recommendations are being adapted in light of the continuing dry weather, and I remain positive having seen just how much plants can do in healthy soils despite being given so little.