Crop Watch: Struggling beet and yellow rust in the South

Winter crops on light land and spring crops are suffering in the dry conditions. In the East, one agronomist described sugar beet as having a “torrid time” with some fields still to emerge as seeds wait for moisture.

In the South East, yellow rust in winter wheat is the main concern as farmers and agronomists struggle to keep up with the disease.

East

Rory Kissock, Farmacy (Essex, Herts, Cambs and Suffolk)

Things here in the East are similar to last year. April showers definitely haven’t materialised and we are now in desperate need of a good rain.

Winter drilled crops on heavy land are holding on due to the excess rainfall over the winter months. Light land crops, however, are starting to struggle .

Winter wheat growth has been slowed by some very cold overnight temperatures which have caused T1 applications to be a long, drawn out process – the last of these will have just been finished on late-drilled crops.

See also: What farmers can do to minimise rising alternaria threat in potato crops

The majority will be looking towards T2 applications and discussions around product choice are happening now.

With little rain on the forecast and low disease pressure, the temptation to cut back on fungicide spend will be high. Growers should remember that the flag leaf contributes 40-50% of the final yield, which is down to its contribution towards photosynthetic activity which leads to grain fill.

All fungicides work best in a protectant situation and the T2 application is an insurance as to what the weather is going to do rather than what it has been doing – reducing rates now to save money could prove costly should it turn wet.

Ears emerging

Winter barley is moving through the growth stages very quickly and there are some crops with ears starting to emerge. The very dry conditions reduce the risk for two main wet weather diseases, rynchosporium and net blotch.

However, the lack of rainfall increases crop stress which can increase the risk from mildew, ramularia and rust.

Now is probably the last chance to check crops for final growth regulators (if required). Remember that growth stage 49 is the cut-off for trinexapac-ethyl + prohexadione and ethephon + mepiquat.

One crop which has loved the recent sunshine is oilseed rape.

Most crops are still in full flower and aren’t suffering from the dry conditions due to having their roots into the moisture at depth. The potential for these crops looks very good.

Flowering sprays have been delayed due to the dry conditions, but as flowering declines and the forecast shows some rain showers the sclerotinia risk increases and fungicides should go on.

Sugar beet is having a bit of a torrid time. It’s amazing how some crops are managing to find moisture.

Crops range from first pair of true leaves visible down to seed sat in the dry, waiting for rain.

First herbicide applications are going on. Actives such as phenmedipham, ethofumesate and metamitron are a great starting point to a programme.

They offer a broad-spectrum approach while in low doses being generally kind to the beet.

If you have fields with different growth stages, ensure your chemical application is tailored to the smallest beet in the field to avoid any crop damage.  

West

Will Spurdens, Ceres Rural (Shropshire and Cheshire)

We’ve now finally had a decent rain with most local areas receiving close or up to 10mm over the weekend.

This will dramatically help crops move on, especially the recently drilled spring crops which were beginning to struggle due to the lack of moisture.

As far as winter crops go, winter wheats have all had their T1 fungicides now in a fairly timely manner, and our thoughts are turning to T2s, the most important fungicide timing in the winter wheat calendar.

Choice of chemistry will depend on disease pressure, crop potential and what was applied at the T1 stage.

Growth regulation may be needed in some very fertile sites, but generally our programme so far should have created some well-standing crops.

Winter barleys have nearly all had their T2 fungicides, with awns showing.

Crops are in good order and disease pressure has been very low.

Winter oats have received their main fungicide and growth regulation applications, and I shall be keeping an eye on crown rust as we go through the season.

Winter rye programmes have also been completed and are generally looking well.

Final applications of fertiliser are going onto wheats, with some growers cutting back due to prices and crop potential but others sticking to their original programmes and pushing for yield.

Spring crops

Spring crops have all been drilled into good conditions with most emerging well.

The only areas where this is not the case are heavy, cloddy seed-beds where the newly planted seed has not been able to find any moisture and thus has not chitted, so hopefully after the recent rainfall these areas will begin to fill out.

Maize drilling has largely started and pre-emergence herbicide applications are going on. Even in dry seasons it acts as a holding spray and allows the uncompetitive maize plant to get going.

All fodder beet is just starting to poke through, and the second post-emergence herbicide applications are being applied.

Maincrop potatoes are now planted and pre-emergence herbicides applied.

I shall be walking these regularly for weed and crop emergence in the coming weeks.

Writing this on the first bank holiday in May, I’m puzzled to where April has gone, but I’m sure I will be saying the same come the next bank holiday…

South

Justin Smith, Procam (East Sussex)

The game we’re currently playing down here in the South East is called “rust chase”, and the question being asked is, “can the agronomist keep up?”.

Despite recent T1 treatments of Vimoy (isoflucypram) and Cello (prothioconazole + tebuconazole + spiroxamine), I have been writing recommendations for some fields of Skyfall winter wheat to receive a T1.5 application of 0.6 litres/ha of Deacon (tebuconazole) plus 0.4 litres/ha of Retengo 200 (pyraclostrobin).

The specific aim of this interim treatment is to help contain some rapidly cycling yellow rust infections as I feel we are truly seeing the strength of the new Yr15 strain.

Here in the South East, yellow rust is evident in many varieties, even more so where T0 fungicide applications were missed.

It would seem this particularly voracious strain holds back for no one and doesn’t seem overly picky on which varieties it infects.

Net blotch and brown rust are easy to find in many winter barleys, which means the T2 fungicide treatments that I recently wrote are hastily being applied.

I fear the situation will still need to be monitored closely for at least few weeks before any gates are firmly closed.

Drought stress

I promised myself I wouldn’t talk about the weather, but it cannot go unmentioned. According to my gauge we received just 5mm of rain in April, following on from a relatively dry 30mm in March.

The inevitable drought stress is certainly not helping disease pressure as winter crops struggle to maintain a healthy balance of nutrients during their period of rapid growth.

Spring crops are also starting to look sorry for themselves and are currently receiving foliar nutrients such as zinc and manganese to try to mitigate tiller loss and maintain green leaf area.

Maize drilling has started in earnest, despite attempts on my part to dampen enthusiasm: having received overnight frosts up until late April, and with the continuing drought, I have been urging caution not to rush at things.

From experience, a maize crop which hits the ground running will soon catch up and will usually cost less to grow than the crop that went into less-than-ideal conditions three weeks earlier.

North

Mary Munro, Munro Agricultural Consultancy (East Lothian)

Rain earlier in the week was very welcome. Fertiliser has washed in and most crops have jumped in response to the moisture.

For a brief but enjoyable moment all combinable crop work was up to date, including spraying. Potato planting is in full swing now, with soil temperatures slowly creeping up.

Winter wheat is now getting T1 treatments – mostly SDHI plus azole, with septoria the main target.

I have seen virtually no yellow rust in winter wheat this year, which proves how different the seasons can be.

Growth has been slow and wheat is seven to 10 days behind last year, largely due to the cold temperatures.

There are some signs of barley yellow dwarf virus appearing now, but the true extent of infection remains to be seen.

Ramularia risk

Winter barley awns are just appearing now and T2 applications are on.

For most this includes a dose of Terpal (ethephon + mepiquat) following earlier chlormequat, plus disease prevention.

I resisted using Adepidyn (pydiflumetofen) last year as it was so dry, but this year the risk of ramularia must be higher, so it is getting tried out by my growers on the crops with decent yield potential.

The cost of any new chemistry can cause hesitation, especially with grain prices depressed, but existing options are not great for ramularia in my opinion.

Oilseed rape is less of an economic headache, and all the crops in my area are in full flower and looking good – not that that is ever an indication of yield.

For rapeseed in the south of Scotland, there are no further fungicides planned. Growers north of the Tay will go again at late flowering.

Spring crops are now covering the ground a bit better as the third leaf and maybe a tiller appear.

I like to get the weeds done early while they are small, and apply manganese to pretty much everything I walk. In a dry season, one fungicide is enough for these crops, but we might end up planning for two this year.

In that case T1 will be a fairly basic prothioconazole-based option. I am inclined to go with that and some sulphur, then possibly follow up with more modern chemistry at T2.