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Stunted patches in dd spring barley

Discussion in 'Direct Drilling Crops & Agronomy' started by Howdenshire Farmer, May 19, 2017.

  1. Anyone seen these symptoms before:
    My s barley has patches of stunted plants in it as shown below. The biggest and worst affected patch is shown in the first pic. Smaller patches like the other pic are more common. Many, but not all, of the smaller patches have healthier plants in the centre like the pic. The patches have a distinct edge.
    The pic with the coin shows roots from an affected patch and the other is from a healthy area.
    The diseased roots are smaller and there is a distinct length of narrow stem between the crown roots and the seed.
    Since it rained last saturday night the healthy barley has grown tremendously and the patches are, if anything, going backwards.
    The worst affected field was s barley last year (with over winter cover). Barley after oilseed rape (and a cover crop) is less affected. There appears to be a correlation with soil type. Affected crops are on my lighter sandy soil. Crops on my heavier soil are ok although they were drilled about a week later than the sand.
    I have some s oats on the sandy soil (after wheat and a cc) and they are ok.

    I suspected that it was a ph issue initially but there is no difference between affected and healthy (both pH 6.5).
    In any case the patches wouldn't be so distinct if that was the case.

    In the worst field, part is drilled with C2 seed dressed with Raxil Star and the remainder is undressed home saved seed. Both are equally affected.

    I also wondered if it was damage from the fungus gnat larvae that were very numerous coming out of winter.
    (@RTK Farmer found the same and identified them.)
    I think the crop would grow away from the damage if it were them and I cant see any sign of them now.

    A brief google session has lead me to think it could be caused by Rhizoctonia. Most of the info on that is from Australia so I am not sure if it is equally applicable here.
    It is characterised by root damage in sharply defined patches and second cereals (esp barley) are particularly vulnerable. It is favoured by no-till.
    I will send a sample to FERA next week for testing.

    I also came across a US paper from 1992 that showed a link with the timing of cc destruction (although the cc was wheat).

    Pithium is another possible cause but I think Rhizoctonia is favourite


    big patch.JPG disease coin.JPG healthy 1.JPG small patch.JPG
     
  2. mikep

    mikep Member

    Looks like root knot nematode. Hope it's not but if it is It's the new kid on the block and really goes to town on spring crops but they can grow away if small infection. There are patches all over this area of heavy weald clay and the funny thing is that it seems to change the soil structure to more friable than previously. We get areas that are permanently bare even most weeds cannot survive but do get some that thrive.
    Fingers crossed I am wrong.
     
    Howdenshire Farmer likes this.
  3. Dan Powell

    Dan Powell Member

    Location:
    Shropshire
    I have the exact same thing on one very sandy field of spring barley. It seems worse near one particular hedge and I had thought BYDV as this field had bad BYDV last year in winter barley. It then had a massive cover crop that was kept volunteer free with falcon. We grazed it bare and no tilled with a disc drill. The other block with same agronomy/rotation etc was drilled with a tine drill and has none of these patches but is slightly heavier soil. Agronomist thinks pH as I am using a lot of ammonium sulphate but the previous soil test was pH 7.3 so seems a bit unlikely. Other thoughts were manganese deficiency but why only in well defined rings and patches?
     
  4. mikep

    mikep Member

    Took these this morning RKN
    IMG_20170520_084350102.jpg IMG_20170520_084151661.jpg
     

    Attached Files:

  5. The Aussie info I have seen suggests that Rhizoctonia is reduced by cultivation, even by a tine drill.
    You could send a sample to the plant clinic at FERA at Sand Hutton for diagnosis. The website tells you how. It isn't cheap but the first step to managing it is to identify it correctly. I think they can test for nematodes too.
     
    TelesnaAg likes this.
  6. colhonk

    colhonk Member

    Location:
    Darlington
    Are they little maggoty things crawling out of the roots?
     
  7. Timbo1080

    Timbo1080 Member

    Location:
    Somerset
    When you described the necking on the roots/stem, that was my instant call too. Never seen it before until this autumn in the OSR. The plants then never get away. Interestingly, the reason given for our outbreak of Rhizoctonia in the OSR, was sudden and intense reduction in the moisture content of the soil, resulting in a reactionary sporulation of the Rhizoctonia, which then infected the OSR - The OSR was subcast. The only areas affected were where we didn't roll the OSR immediately after drilling, but waited a until the following morning.....Small patches of plants were affected, while neighbouring plants on the periphery were absolutely fine. Trouble was that there were lots of small patches. Was told that azoxystrobin at epic rates in the soil would prevent it, as per spud growing, but obviously too late by the time you have it.
    Would be really interested to know how your results come back.
    Good luck,

    Tim
     
    Howdenshire Farmer likes this.
  8. mikep

    mikep Member

    Won't see them with the naked eye but under magnification they are worm like.
     
  9. Kevtherev

    Kevtherev Member

    Location:
    Welshpool Powys
  10. silverfox

    silverfox Member

    Don't know Kev
     

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