Farming News - Watch out for late emerging weeds as T2 timing looms

Watch out for late emerging weeds as T2 timing looms

11 May 2012. If April showers bring May flowers were in for an abundance. Watch out for late emerging weeds in crops as reports of wild oats and cleavers appearing even after comprehensive herbicide programmes. T1 fungicides still delayed more particularly in the South and East.

 

  • Septoria risk remains high.
  • T1 fungicide timing in winter wheat a priority.
  • Flag leaf out in some forward wheat crops.
  • Yellow rust returns where T1s delayed.
  • Awns emerging in winter barley.
  • Sclerotinia control delayed by weather.
  • Late emerging wild oats and cleavers in winter wheat.
  • Recent flush of weeds in sugar beet.

 

Winter Wheat

 

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Wet weather raises Septoria risk.

South.  All the wet and wind have caused some major application problems with T1 applications delayed by 2-3 weeks on some fields. Soils are now very wet in places with standing water not uncommon – I have never seen even normally free-draining sandy loams so wet at this time of year. Most later sown (late October+) crops are now between GS 33-37 and September/early October sown crops of Gallant, Solstice and Xi19 are now at GS 37-39, flag leaf emergence.
Brown rust: only really present now in crops where T1 application timings have been seriously delayed/compromised and mainly in thicker crops of September sown Claire, Target and Solstice
Mildew: most crops remain free of any re-infection to date – only exception is a few lush crops of Gallant/Solstice.
Yellow rust: no new foci or leaf pustule stripes seen, but remaining vigilant particularly on susceptible crops where T1 spray intervals since T0 have stretched beyond 21-28 days
Septoria: current conditions with frequent rain splash events remain very favourable for infection and any crops not yet sprayed with a T1 will have significant latent infections in all unprotected leaves, and even the new SDHIs are unlikely to eradicate this from leaf 3, resulting in significant infection of leaf 3 – all outstanding applications need applying urgently to minimise infections of leaf 2 and the flag. Where T1 applications have been applied, T2 fungicides should be timed at 14-21 days after T1 applications were made to ensure maximum eradication and protection of the top leaves is achieved – but don’t apply before flag-leaves are at least 2/3 emerged on the main shoots. This will undoubtedly be the worst Septoria year since at least 2008.
Eyespot: a lot of obvious eyespot lesions now appearing in many September/early October sown crops (particularly Cordiale, Gallant and Solstice) due to the highly favourable weather this year – some mid-September sown Gallant is beginning to lodge now due to severe penetrating eyespot despite the use of Tracker in mid-April @ T1.
Weed control: all spring applications of Atlantis have now been completed – so far control of black grass is looking perhaps more comprehensive than some Autumn applications have been.



Eastern Counties. The weather has been pretty horrendous over the past couple of weeks and is making this season quite difficult. Crops are incredibly thick and where un-treated disease is rife. The main concerns at the moment are keeping the crops stood up with Terpal in short supply. Majority of crop at GS 32-33.
Brown rust: now showing on untreated varieties.
Yellow rust: high levels in untreated crops which are susceptible. Also now showing on crops which were treated a month or so ago.
Mildew: the more backwards crops showing quite a lot of mildew.
Eyespot: showing on crops but is not really penetrating the leaf sheath.
Septoria: showing in the older leaves and with wet weather it has a lot of potential to spread. Invicta seems to be quite badly affected.
Take-all: starting to see symptoms in second wheats even in some latitude treated crops.
Weed control: late emerging wild oats are appearing right in the bottom of the crop canopy – even following sprays of Atlantis / Broadway star. Cleavers are also emerging.

East Midlands. All crops have final leaf 3 out and many forward crops have final leaf 2 emerging up to 20% out in some crops. Fields very wet with some localised ponding – some crop damage in gateways and on headlands where turning but lesser of two evils when sprays delayed. Final main N to go on when spraying done and weather allows with N for bread varieties aimed at mid May.
Brown rust: none seen.
Yellow rust: seen in Oakley at low level where T1 delayed due to rain.
Mildew: levels remain low although a bit on the lower stems of Humber but not a significant levels.
Septoria: plenty there in the bottom of the crop and time will tell whether T1s have held it. Many crops have clean leaves 4 and 5 but the gap between T0 and T1 is getting longer.
Eyespot: surprisingly holding steady and generally not penetrating especially where an eyespot T0 was used.
Weed control: some broad-leaved weeds starting to emerge in bases of crops with the wet conditions but many crops clean and good crop competition will see them through.

West Midlands. Earliest crops now have the flag leaf poking out with about 20% of the leaf showing. This is mainly early sown Grafton which is doing its normal trick of accelerating from T1 to T2. early sown Humber is also poking the flag leaf out . A lot of the remaining varieties appear to have come to a grinding halt over the last 3 weeks with barely leaf two out and some are twixt leaf two out to leaf 3 out. All T1 applications were completed over the last weekend which means that some will have had a T0-T1 gap of some 5 weeks! BYDV obvious in some crops but none where Deter seed dressing used.
Brown rust: none seen.
Yellow rust: traces on Oakley where T1 delayed..
Mildew: none seen.
Eyespot: developing well in some crops. Lodging risk will be an increased issue for those that have ignored the eyespot at T1.
Septoria: lots of septoria in the base of many crops but don't confuse with leaf scorch from earlier fungicide applications.
Weed control: rain has encouraged a recent emergence of broad leaved weeds including cleavers and volunteer oilseed rape.

North East.  Generally growth stages are close to 'normal'. In most forward crops tip of flag leaf is just visible.  Most crops, ,however, have leaf 2 emerging and flag leaf will be at least another 7 days. 9mm of rain over last 7 days. Fields are travelling well and all T1 applications are now completed. T2 fungicides planned for from 20th May, and for most crops a low rate of PGR will be included. T2 Aviator Xpro @ 1 L/ha planned for Duxford, JB-Diego and Beluga. Older chemistry still on Invicta, Scout and Warrior will be Opus + Comet.
Brown Rust: no new infection seen.
Yellow Rust: no new infection seen.
Mildew:
no new infection seen.
Eyespot: more lesions penetrating the outer leaf sheath seen this week.
Septoria: recent weather suggests that high levels of Septoria should be seen. In practice it is well within acceptable levels even in some dense crops of Oakley and Viscount.  However, there may well be significant levels of latent infection so T2 fungicides will be applied promptly once flag leaf is at least 50% emerged.
Weed control: Areas of poor control of blackgrass becoming more evident now. There are going to be some fields with significant patches come the Summer. Also, since the rain started more broad-leaved weeds have come through so there will be some herbicide needed with the T2 fungicide in a few fields. Cranesbill continues to be  ‘BLW  of the year'.

 

Winter Oilseed Rape 

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Heavy rain and high winds takes its toll.

South East. All crops now between mid to late flowering. Most crops should finish flowering in the next 2 weeks now.
Phoma: no significant renewed spotting seen to date.
Light Leaf Spot: no new infections seen.
Seed Weevil : low levels of adults seen in quite a few crops in the last 7-10 days whenever sun is out.
Mealy aphids : colonies beginning to be noted around headlands in particular.
Sclerotinia: this looks to be a potentially very high risk year and any crops that have not had a fungicide for 18-21 days+ now need spraying urgently.

Eastern Counties. Crops in full flower throughout now and have spent most of the flowering period so far wet, with only the odd day when the rape canopy would have dried out. 20 pod set + on the most forward varieties.
Light leaf spot : remained at low levels none on upper leaves, recent conditions have not been conducive to spread of this disease.
Mealy aphids : in small clusters scattered in some crops.
Pollen Beetle: surprising amount of recent pollen beetle damage on late flowering pigeon damaged crops considering the recent low temps and wet weather.
Sclerotinia: still a few outstanding first Sclerotinia sprays but not many. Now adding ½ rate  Filan to Proline where we have been delayed rather than Amistar. Recommending good doses as we may not come back to these late treated crops with a 2nd application.

 

East Midlands. Crops at 15-20 pods formed and look well. There are reports of laid crops from last Sunday's wind and rain, DK Cabernet being the main culprit apparently. With frosts being expected this weekend some crops could take a double hit.
Light Leaf Spot: just odd pieces but nothing of concern.
Seed Weevil : no weevil seen yet.
Sclerotinia: with the continued wet weather Sclerotinia sprays will be aimed at 3 weeks after the first. Crops have a lot of flowering to do and the colder weather this weekend will slow then down further.

West Midlands. Some crops of Vision now loosing petals quickly, but other crops are at full flower. More heavy rain during the week has resulted in fresh cases of lodging.
Phoma: no new infections.
Light Leaf Spot: very low levels which have not developed.
Seed weevil:
none seen yet.
Sclerotinia: most Sclerotinia treatments now completed but the earliest ones were over four weeks ago, for these crops we may go again.

North East. Crops continue to flower strongly, and are currently at densest yellow. Pods are setting well. Fields have travelled well for first Sclerotinia spray. There are a few crops with some plants leaning a little, but no lodging seen in the area.
Phoma: no further infections seen.
Pollen Beetle: crops coming into flower are no longer at risk.
Sclerotinia: The wet conditions are highly favourable to Sclerotinia infection, but the risk is slightly tempered by the low temperatures. All crops had 0.4 kg/ha Filan, and 0.75 L /ha Amistar is planned for aprox. 21 days later. It looks as if its going to be a long flowering season so a long period of protection is required.


Winter Barley.

South. Crops now generally at awns/ears emerging – too late for any further PGR applications. Siltra or Proline+Comet are due to be applied as T2 applications.
East. Some have flag leaf out and awns poking through. Disease control is good. Where Terpal required second spray will be applied soon. Where no Terpal is required we will wait until first awns are visible. Siltra or Fandango will be used depending on the crop and what is left in stock.
East Midlands. Final leaf 2 now out and expect flag to be out in next week or so. Disease levels remain low although with all this rain pressure is on.
West Midlands. Awns emerging on most forward crops. Even crops with two cyper applications are showing signs of BYDV.
North East. Flag leaf fully emerged in many crops now, and  tips of awns just visible in a few. Most crops are well tillered and Cerone has been applied at various rates over last 7 days. The hybrid varieties are much thicker than intended, but at least the stems seem thick and strong following the early PGR program. T2 fungicide planned for soon as awns mostly emerged.  Siltra Xpro @ 0.4 L/ha  for all crops.

 

Sugar beet

Recent slightly warmer conditions have resulted in a noticeable improvement in growth but crops are well behind recent years (possibly a month behind). Bird grazing continues and now pigeons in small groups are the main culprits. Bird scaring tactics are needed.

The pre –emergence herbicides seem to have now run out of steam and large flushes of weeds are appearing. Spraying continues to be delayed and doses of herbicides are increased accordingly as weeds and beet become larger and stronger.  We have usually finished weed control in beet by mid- May. I can see we will be spraying well into June this year. Main weeds are black bindweed, pansies, volunteer oilseed rape and cleavers (on better soils but they are becoming increasingly more widespread in beet crops especially where potatoes are also grown in the rotation).