Crop Watch: Soggy weather triggers fusarium alert

The rain in recent days has been welcomed by arable farmers, as it will keep parched crops going through the critical grain-fill period. All crops need now is some sunshine.

However, the rains have also increased the risk of fusarium ear blight in wheat, arriving before T3 spraying had been completed. 

Another downside is that the intensity of the monsoon conditions have severely tested plant growth regulator programmes, with some wheat and barley crops going down.  

Marion Self

Marion Self

East: Marion Self

AICC/Prime Agriculture (Suffolk)

As we bathed in the mud at Cereals, many growers wished they could have completed their winter wheat ear sprays before the rain.

However, there was enormous comfort that the wet weather was doing more for yield than anything from a can could do.

Heavy, tall crops of hybrid barley have been blown around and, in some cases, beaten to the ground. However, in the main, crops have stood well showing good yield potential.

On most soils, crops have now received enough moisture to carry them through to ripening. What they need now is lots of sunshine and average temperatures to maximise grain fill.

See also: What potato growers need to consider ahead of diquat ban

In wheat, wet conditions during flowering will have encouraged fusarium, late septoria and yellow rust infection. Brown rust infection is also developing in susceptible varieties.

This season, many crops received their ear sprays post anthesis and will have been at risk of fusarium infection during this susceptible time.

Insect threat

In pulses, continue to monitor aphid colonies that can build quickly as temperatures warm. Also check pea crops for pea moth and pea midge.

Remember, pirimicarb (such as Aphox) can only be applied once. Pyrethroids only offer partial aphid control, butin peas, thiacloprid is another option – although more expensive.

Pulse growers should continue to monitor spring beans for bruchid beetle. The trigger for control at pod set is when temperatures reach 20C on two consecutive days.

For milling wheats, many growers have planned foliar nitrogen to achieve quality specifications. It can be applied from watery to milky ripe, but take care to apply in cooler, dull conditions to avoid scorch.

On many farms, control of grassweeds and barley yellow dwarf virus (without neonicotinoid seed treatments) will shift the main time of cereal drilling into October. 

How will this affect your cropping choices and variety selection? Later-drilled crops will require tweaks to their general management, including changes to seed rates, nitrogen planning and other spring inputs.

Antony Wade

Antony Wade

West: Antony Wade

Hillhampton Technical Services (Herefordshire/Shropshire)

As the saying goes: “Be careful what you wish for.” Those who had been doing rain dances over the past few months are probably trying to backtrack after the week of rain we have endured.

Mother Nature has a way of balancing out the weather over time. It is unfortunate that this balancing has to arrive all in one week.

We haven’t had the rainfall totals of areas further north and east, but 92mm since 8 June has been plenty.

Wheat crops are just starting to flower, and it would have been preferable to get some protection on ahead of this recent rainfall.

Hopefully, the weather will improve and by the time this article is published, most crops will have been sprayed.

Although any fungicide applied will only give moderate control of ear diseases – particularly of fusarium – it is worth trying to minimise the risk considering the increased risk the rainfall has brought.

Crown rust

Oats – both winter and spring crops – will also get a fungicide when the panicles are emerging to protect against late crown rust infection and to keep the grain bright, which is critical if they are for milling.

Barley crops have been visited with trepidation for fear of lodging brought on by the heavy rains and associated wind, with ears gaining in weight, especially when only the hybrid crops got a late plant growth regulator application.

However, so far crops have held up to the buffeting, with just some headland overlaps and ex-muck heap patches leaning.

Spring barley crops are still very disease free and with weed control strategies working well, these are planned for a single spray strategy at paint brush stage. These will be applied as soon as a spray window appears.

Maize crops that emerged well are now in desperate need of some warmth so they can grow out of the pale and sometimes purple tinge they got during the cooler, wetter spell of weather.

I am still optimistic about crop potential in my region, but we now need to see a return to warmer conditions and reasonable sunlight levels in this critical period.

Mary Munro

Mary Munro

North: Mary Munro

AICC/Strutt and Parker (Perthshire)

Like many readers, I enjoyed a wet and muddy day at Cereals and was relieved to see that Lincoln’s torrential rain had not made it north of the border.

We have had plenty of moisture, though, and could do with some sunshine to fill the grains.

Weather is an issue now. The big cereal and oilseed rape crops will not take much of a battering before they start to go down, and even some of the spring malting barley looks as though it could sway a bit too much for comfort.

I generally do not use plant growth regulators on spring barley – the reduction in N for malting normally prevents the crop getting too lush. The exception would be where there is grazed grass in the rotation and a bit of extra fertility in the soil can just be too much on the overlaps.

Most of the spraying tasks are done. T3s are due to be applied to wheats, and the second fungicide on spring barley. I am maintaining reasonably robust rates and product choices on the expectation of continued showery weather.

Yellow rust

Disease pressure is relatively high, understandably, with septoria in wheat and rhynchosporium in barley, but there is yellow rust lurking in the field margins where the sprayer has not quite covered the crop. This tends not to happen north of the Forth, thankfully.

My colleagues and I have been facilitating the AHDB’s Farmbench project and we have our final local group meeting next week, to review the 2018 crop performance.

The variation in results is astonishing, given that the farms in each group are geographically close.

The differences extend from variable costs right through to all the fixed-cost items. The fixed costs are always the hardest to allocate to individual enterprises, but the participants have costed everything to the bottom line.

The discussions are always lively and thought-provoking. Last year was not great for crops, of course, and it will be even more interesting to see how 2019 compares.

Richard Harding

Richard Harding

South: Richard Harding

Procam (Sussex)

The monsoons of last week seem to have now passed. However, the prospect of more heavy rain and potential thunderstorms in the next couple of days mean we may not be completely back to normal just yet.

The rains came just in time and should set the crops up nicely, providing we get the sunshine now to complete grain fill. Some of the barley crops appear to have been hit hardest, with some lodging, particularly on the overlaps.

Some of the better oilseed crops are also leaning and slightly compressed.

The wet, warm, humid conditions as wheat crops flower will encourage the ear blight fusarium/michrodochium complex in wheat, making it imperative to complete T3 fungicides, and even raising the question about T4s to top up late-season disease protection where crops with high yield potential justify it.

Lower aphid risk

Aphid numbers had been building, but the cool and wet conditions of last week will not have suited a rapid increase in numbers, although predator numbers – especially ladybirds – remain high.

The risk of orange wheat blossom midge should also be receding, as conditions last week would not have been conducive for female midges to be flying and laying eggs. Many crops are now into the flowering period and beyond the risk of damage.

The cooler temperatures of last week meant the risk of bruchid beetle was reduced in bean crops, but could return as temperatures rise in the coming days.

Continual monitoring and regularly checking with Syngenta’s BruchidCast will aid decision-making about insecticides.

If there was any doubt about the second fungicide application in pulses, last week’s weather will have provided perfect conditions for disease development.