Crops are looking full of potential and the warmer temperatures forecast this week could see a rising disease risk. There is also optimism with spring crops which have been established into good seed-beds. 

And with oilseed rape finally flowering, agronomists’ thoughts have turned to flowering spray strategies in the coming weeks.

See also: Tips on tackling five weed issues in no-till systems

West

Antony Wade

Hillhampton Technical Services (Herefordshire/Shropshire)

Recent weather has been “flip-flop” – not so much for the need for summer footwear, but in the way that we seem to swing from high teens temperatures in the day to a northerly blow with wind chill close to freezing and overnight frosts.

That being said, crops in my region look pretty good with plenty of potential.

Oilseed rape crops are starting to flower. By the time this article is published, some forward crops will, hopefully, have had a mid-flower spray to protect against sclerotinia infection.

Sclerotinia risk with current soil temperatures may be low, but the forecast is for warmer weather as we run into Easter.

We only have protectant activity from fungicides, and the devastating impact a serious sclerotinia infection can have, and with current commodity prices, means protection is imperative.

Recent applications of plant growth regulators (PGRs) have done a job in controlling main raceme height and dominance.

OSR pest

Pollen beetle had started to colonise crops but not at threshold levels, and with widespread resistance, plenty of beneficials and crops coming into flower, spraying was just not a consideration – subconscious integrated pest management in operation.

Winter barley crops have generally had their first spray with growth regulator. How effective these will be with the colder weather, only time will tell.

To date there hasn’t been a significant spring flush of weeds, so herbicide was deployed only where there was wild oats or the now ubiquitous groundsel.

Disease levels were starting to develop, so a strong T1 of Ascra (bixafen + fluopyram + prothioconazole) was the generally preferred option.

Winter oats are well tillered, but with some leaf reddening in crops a multi-nutrient has been recommended and on stronger crops some plant growth regulator.

For oats I exclusively use Canopy (mepiquat + prohexadione) as it seems to be the kindest on the crop.

This year more than ever, with chlormequat supply issues, I have had to get Canopy on farm to ensure we have enough product for this valuable break crop.

East

Marion Self

Prime Agriculture (Suffolk)

Brimming with potential! Crops are moving into a period of fast growth, lifted by warmer temperatures, longer day length, recent rains and nutrition.

Our job now is to maintain the health and structure of the crop canopy to maximise yield potential and profitability.

Early to mid-September drilled wheats have leaf 3 emerging and are at or approaching the T1 fungicide timing.

Leaf emergence varies according to drilling date and variety, so individual crops need checking carefully for correct input timings.

Cold weather at the beginning of April temporarily slowed the septoria and rust epidemic, but these diseases will increase quickly following recent showers and warmer days.

On most crops, T0 fungicide and PGRs have been applied and are protecting the canopy until a well-timed T1 mix.

Robust T1 fungicide mixes tailored to varietal susceptibility and drilling date should be applied to protect yield and our investment in other inputs such as fertiliser.

If you have reduced nitrogen inputs, remember that the canopy should be kept clean and healthy so that each leaf layer can contribute as much as possible towards yield.

Winter barley crops are also receiving robust treatments for disease control with PGR at early stem extension (GS 30 to 31).

These crops look much healthier as new, clean leaves emerge and the canopy extends.

Establishment

Spring crops are establishing well, requiring adequate early nutrition as they begin to grow rapidly, particularly nitrogen and sulphur.

Early weed control is also important before the canopy closes and the growth stage allows a good choice of herbicide.

Sugar beet has been drilled into good seed-beds with moisture, and is mostly emerging uniformly. Newly emerged crops should be treated kindly with low-dose herbicides timed to avoid frosts. 

Early to mid-flowering sprays on oilseed rape should be considered. At current prices only a small increase in yield will give a large additional return on investment.

Winter beans are also approaching early flower; many of these crops would now benefit from treatment with the appropriate micronutrients.

Finally, remember it’s a busy time for the sprayer, often moving between different crop types, which makes logistics and sprayer hygiene particularly important. 

North

Mary Munro

AICC/Strutt and Parker (Perthshire)

Spring sowing was largely completed in the warm week at the end of March, and these crops are emerging nicely.

We have had a lot of rain in the past week or so, which has helped get them off to a quick start.

After two very dry springs, this one looks quite different already.

Some barleys had a pre-emergence Liberator (diflufenican + flufenacet) to tackle annual meadow grass, and I like to get the broad-leaved herbicide on around the two-three leaf stage of the crop, and catch the weeds when they are very small.

This enables us to get two doses of manganese on – one with the herbicide and another at T1.

Once stem extension begins, the yield response to manganese reduces, although the visible symptoms can still be alleviated.

Winter crops are really starting to move through the growth stages now, and most wheat has had a T0, with only the latest, most backward crops yet to be sprayed.

Low disease

Disease levels are relatively low – there was a bit of yellow rust in evidence a month ago, but the weather (and possibly the T0) has done a good job of knocking it out.

Conditions are still quite cold, and I have been wary of issuing recommendations up till now, as we have had a long run of frosty nights.

However, I don’t want to end up with a silly short gap between T0 and T1, nor do I want to roll them together.

The yield response to T0 is low, but with grain prices the way they are, a small percentage response will more than pay for the treatment.

Winter barleys have been slow to get away – a visit to Northumberland 10 days ago really demonstrated the difference 60 miles can make, as their crops were well into stem extension, while mine were just right for the T1 of PGR, Siltra (bixafen + prothioconazole) and manganese.

Our OSR crops are inching their way into flower, and they are remarkably even this year – it is a pleasing sight to see a field turning bright yellow without gaps.

They will get a mid-flower treatment with Aviator (bixafen + prothioconazole), and for most of them that will have been the only fungicide applied.

South

Richard Harding

ProCam (Sussex)

A rather frustrating spell of weather last week, with up to 8mm of rain in places, delayed field work on some parts of the Downs, but the rain has at least washed in some of that expensive fertiliser applied.

This was the main application to crops as the wet and wind prevented much in the way of spraying.

The next priority will be a PGR application to prevent forward cereals from becoming too top-heavy. Crusoe, drilled in mid-October, is now at GS 31.

The weather prevented a T0 fungicide spray a week to 10 days ago, which means it is important for both PGRs and disease control that the T1 fungicide application is well-timed.

Cold frosty weather has delayed some grassweed control. However, where applied in good conditions, the results against some sterile brome, a common problem in no-till systems, has been pleasing and worked well.

Winter barley crops are catching up, having been slow to get going where direct drilled. T1 fungicides have been applied at around GS 31 or will be very soon. 

Barley disease

There is a lot of flecking in crops, which is more down to physiological speckling associated mainly with the large daytime temperature range 10-14 days ago.

Rust has also been very noticeable on the conventional varieties. There is now a growing amount of net blotch which will warrant the addition of pyraclostrobin to slow this disease.

Small patches of barley yellow dwarf virus are now clearly visible in winter cereals, and in places this has killed the crop, especially where there was direct transfer of aphids as a green bridge from dying volunteers onto the emerging crop.

This was mainly where a timely autumn insecticide application was difficult. 

It is even more obvious in oat crops where the distinct purpling stands out like a sore thumb. 

Forward winter oat crops are having a PGR applied of straight chlormequat and a penetrant adjuvant at around GS 30-31.

This will be followed with an application of sulphonylurea chemistry for broad-leaved weed control.

Oilseed rape crops are at last recovering from pigeons, where all leaf area was completely grazed.

The better, more forward crops are now flowering well, but have not received a flowering fungicide, which will be based on a mixture of prothioconazole and azoxystrobin.

Spring barley is establishing well, as are all spring crops this year, with the spring barley crops now having received half of their nitrogen requirement. Overall, crops look well and full of potential.