Kerria japonica 'Pleniflora' blight - Treatment Query

I I live in a wooded area at the highest point of South East London. I have an established row of Kerria japonica 'Pleniflora', planted 16 years ago, providing a high hedge for privacy.   After usual superb flowering and good leaf growth, at the end of June this year, 2016, all 20 shrubs looked miserable, thin, covered with spots on leaves and some stems, several stems have gone dark brown and died, and 'red' leaves have dropped as if it was autumn. 

I have treated the blight with a fungicide and fed the shrubs but the condition is not stopping, and it looks as if it is spreading to the Cotinus next to it. 

I have been searching online to find out if this blight is anywhere else in the local area or in the UK but so far can only find a reference to an online report of 'Leaf Spot' on Kerria Japonica, caused by Corynespora cassiicola in Korea, in May 2015. The description matches the symptoms on my kerria but there was no solution.

I am looking for a diagnosis. How to treat the disease?  And are there reports of this blight elsewhere in the UK?

Thank you for any information you can provide.

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  • nutcutletnutcutlet PeterboroughPosts: 26,015

    can you upload a photo of the kerria and the cotinus

  • Thank you for reading my query, I attach photos.

    Photo 1 September 2015

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    Photo 2 April 2016

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    Photo 3 August 2016

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    Photo 4 August 2016

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    Photo 5 August 2016

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    Photo 6 August 2016

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    Photo 6 August 2016

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    Photo 6 Cotinus August 2016

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    Photo 7 Cotinus August 2016

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    Photo 8 Cotinus August 2016

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  • I have cut mine down to the ground but new shoots are still showing rust/blight. So have decided to dig as much root out as possible ( the plant has been in this spot for some 40 years and up to last year has always given a wonderful show). An American sight suggest destroying it completely, but I can,t get all the roots out. Can I treat the remaining roots with a fungicide, if so which ?

  • GinkgoGinkgo Posts: 1

     

    I have the same problem could you tell me if you managed to clear the blight eventually??

  • I also discovered the blight in my garden when the house was vacated by tenants by which time it was too late and all the bushes are completely dead.

  • I first noticed my kerria looking unwell last year and this year has spread to the largest patch mingled with honey suckle. The roots were extensive and keep throwing up shoots which sooner or later die. I'm very sad to lose this shrub I have had it at least 30yrs. 

  • Hi my Kerria Japonica Pleniflora has not flowered this year and looks dead.....🤔 no idea why! It has flowered  last few years not  sure how old it is as was already in the garden when we moved here. We live in Chester. Any advise really welcome as thinking need to dig it up and want to replace with another one ....? 
  • Hi I know these posts are years old, but I live in America, so just found this. we are having that kerria blight too. its in an old family plant. has anyone managed to save their plants yet?
  • CeresCeres Posts: 1,756
    I've just noticed this on my kerria and as I seem to share the plant with the neighbours, they have it too.
    Personally I can't be bothered with spraying horrid stuff every spring and then throughout the growing season so the plant will have to go.

  • GGGardenGGGarden Posts: 3
    Hello
    I posted the photos and query back in 2016, and am sorry to report the Kerria never recovered, and other local Kerria planting also died.  I never found out what caused the deterioration of the shrub; a local gardener thinks the cause was drought and a lack of regular pruning.
    I removed the Kerria "completely" at the start of 2019, and new healthy-looking samples still turn up, only to be removed.  The soil has been replaced and I will plant climbers and a small tree this autumn.
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