Crop Watch: Rust pressure remains high in wheat

The improved weather in recent weeks has seen wheat fungicide timings get back on schedule with the T3 ear sprays being currently applied.

However, the rust threat remains high, as shown by the “devastatingly high levels of yellow rust” in spray misses in the West and the North.

In addition, our agronomists highlight that now is a good time for farmers to review their blackgrass strategy and consider making changes for next season.

david martindaleNorth: David Martindale

Arable Alliance (Yorkshire)

May proved largely to be a dry month and crops have responded well to some warmer weather. More recently, coastal areas have had either sea mists or heavy cloud, so despite the dry conditions a distinct lack of sunshine will not be helping grain filling of either winter barley or oilseed rape crops. 

Late-sown spring cereal and pulse crops are racing through their growth stages and look well.

Winter wheat crops are receiving their T3 fungicide mixes. Thankfully, the top three leaves are clean, which is crucial, as these are the most important for building yield. The dry weather in the past few weeks and fungicide timings back on schedule has recovered the disease control situation from the difficulties at the T0 and T1 timings. 

See also: Why growing a Group 3 wheat may pay off next season

Yellow rust has made a late appearance in spray misses in field corners or around telegraph poles. While yellow rust in these areas is unsightly, it does reinforce just how well fungicides can control this disease.  

Orange wheat blossom midge numbers have been higher than in recent years, but it is such a localised pest, with numbers caught in traps varying significantly across the same farm. A continued shift to growing varieties resistant to this pest is sensible as a risk management tool, as well as reducing insecticide use.

Blackgrass control

Overall, blackgrass control has been good this season, but mapping any grassweed issues is worthwhile. Even more worthwhile is making time to rogue any grassweeds, which in my opinion is one of the most important investments of the year.

Spring barley crops have a huge range of drilling dates, with the earliest-sown crops now at the ear emergence stage. T2 fungicides have already been applied at the awns-emerged stage, with chlorothalonil added for ramularia protection. 

Gout fly continues its love affair with spring wheat with multiple eggs laid on the same plant, which in many cases has required a prompt insecticide application.

Spring beans mostly look well, with the earliest crops just beginning to start flowering. Weed control so far has been good due to plenty of moisture for the pre-emergence herbicides to work well, leaving only deep-germinating volunteer oilseed rape and charlock to be controlled post-emergence. 

Black bean aphid populations are starting to build and, in some cases, there are large numbers on individual plants that is particularly early where crops have yet to start flowering. 

Neil PottsWest: Neil Potts

Matford Arable (Devon)

Since my previous article, the weather has done a complete U-turn and we have now had weeks with little or no rain. This has meant everyone has been able to “go like hell” and catch up with spring plantings.

The warmer and drier conditions have helped to reduce the wet weather disease pressure and crops have cleaned up reasonably well. Unsprayed corners of fields are, however, showing devastatingly high levels of yellow rust. This is quite refreshing to see as it demonstrates just how effective the fungicide programmes have been.

Winter barley crops where nitrogen timings were on time are now looking fairly promising, whereas those where applications were delayed are a bit on the thin side to produce a good yield.

Crops of Cassia where T2 applications have been delayed or not made at all are once again showing high levels of ramularia. With the recent warm weather, it is looking like we might even have a relatively early barley harvest at present.

Winter wheat crops and winter oat crops have now responded to N inputs and are looking very well, if a bit on the short side, as the weather was still wet and cold at early stem extension and little growth was made.

Short crops

Due to the late start to spring, many wheat crops have also dropped a leaf, which is contributing to the shortness of crops. Hopefully lodging will not be problem this year.

The spring barley crop this year, although late, is looking good where seed-beds were correct and moisture has not been a limiting factor or looking dreadful where seed-beds were poor and it has been too dry. In many crops, particularly the later-drilled ones, weed germination has been very slow and there have been repeat flushes.

With late planting and rapid growth, fitting in all the applications required has been a bit of a challenge, particularly where wild oats are an issue. With stressful growing conditions, complicated tank mixes have been a bit of a no-no in some situations as well.

The maize crop probably got off to its best start in years this season, with crops emerging quickly, staying green rather than turning yellow and red as in some seasons and growing quickly as a result of both warm days and nights. Many crops are approaching knee high in early June rather than by the beginning of July.

ben pledgerEast: Ben Pledger

Farmacy (Beds/Herts)

Ear emergence in forward winter wheat crops has coincided with the wet, thundery weather a fortnight ago. Even with high disease pressure this spring, most crops are showing good potential after the robust fungicide programmes that have been used to date.

With that in mind, the option to go cheap and cheerful with the T3 fungicide has been ruled out. Prothioconazole has been the go-to chemistry to control both fusarium species and Microdochium nivale. A strobilurin active ingredient has been included for improved control of rusts, Septoria nodorum and sooty moulds and also to prolong green leaf area retention.

Cereals event

For those of you who travelled to Cereals this week, there were a lot of thought-provoking things to look at. However, I’d put money on the fact that one of the first was the varying populations of blackgrass in crops on the way to the event.

Unless you are planning on spraying areas of high populations off, whole cropping or hand rouging, there is little you can do about problem areas this season.

Now is the time to start your blackgrass control strategies for next year though. There are a number of relatively inexpensive cultural controls that can be employed before you even think about reaching for a can of chemical.

These include increasing seed rates, choosing a competitive variety, delaying drilling, extendibg rotations, using stale seed-beds, blowing down and cleanibg out combines between blocks, planning harvesting to reduce the spread of seed around the farm and making sure contractors enter the farm with clean machinery.

Delayed drilling can lead the way to create stale seed-beds to kill off flushes of blackgrass before the crop is even sown. All fairly standard advice, which can be overlooked in the rush of harvest. Make a plan now and stick to it where possible.

Tod HunnisetSouth: Tod Hunnisett

AICC (Sussex)

Earwash time after yet another challenging season, and once again Mother Nature has demonstrated her ability to throw in a few wild cards.

These include wheat flowering when the ear is only half emerged at the end of May, winter barley having had tillers in ear for a month coming back into flower and spring barley demonstrating what looks like 150% germination, splitting the boot five weeks after drilling.

In the south of England, we had a very hot, very wet, very windy last week of May. Unprotected flag leaves were in desperate need of fungicide. Unfortunately, some timings were stretched and in some cases, rust has come back in with a vengeance.

There is yellow rust in Claire (yes, it is still widely grown near export ports) and brown rust in Crusoe – I cannot see this variety lasting much longer after this year. It annoys me that a variety of wheat has the ability to keep me awake at night.

Spring crops

The hot, wet weather has certainly helped the spring crops though. Fantastic establishment of everything from spring barley through to maize, spring oilseed rape and linseed. Manufacturers of growth regulators are laughing all the way to the bank where people increased their seed rates in spring barley.

Spring beans seem to have grown 6in between the time the sprayer started and finished spraying the field. Apparently, last week was the highest-ever measured pollen count in our area – a month before traditional haymaking time.

It will not be long before oilseed rape desiccation tickets. Some will need ultra-high-clearance sprayers. I think rape will be cut before winter barley this year, as this weird secondary flowering looks like it will be hanging on for some time before it becomes fit.

We’re getting to the stage now when all we can do is hope we haven’t upset Mummy Nature too much…