Alder Leaf Beetle at Fitzwilliam

I was walking around Fitzwilliam Country Park this afternoon when I spotted lots of metallic black/blue beetles on the leaves of an alder. I think the alder is Italian alder (Alnus cordata).

Alder Leaf Beetle on Italian Alder

I believe that the beetles are Alder Leaf Beetle. This species has been absent from the UK for about 60 years and it began to be recorded again in about 2004. It is likely that it was reintroduced to the British Isles by the plant trade.

Alder Leaf Beetle (Agelastica alni)

There were many beetles on this and other trees, singles and mating pairs. You can see holes in the leaf in the picture above. This species causes significant damage to alder and can reduce leaves to skeletons. It was recorded at RSPB Old Moor in 2012 and it has been recorded at Wintersett since 2013.

13 thoughts on “Alder Leaf Beetle at Fitzwilliam

  1. Thank you for the information. This beetle has spread rapidly in our area and is now a common sight. Watch out for the shiny black larvae, that have a similar shape to ladybird larvae.

  2. I have them all over a tree in my garden. I’ve never had them before and they are eating holes in almost every leaf I can see. How do I get rid of them? The birds in my garden don’t seem to be interested in them.

    • Eric, as they are an alien species, it would not be unusual if the local birds do not have a taste for them. Unfortunately, I can’t give you advice aout how to exterminate them.

  3. Today I spotted extensive infestation of young alders growing on the bank of the Leeds-Liverpool canal near Apperley Bridge.
    Many leaves had been reduced to skeletons.

  4. Today I noticed extensive infestation of young alders growing on the bs k of the Leeds-Liverpool canal.
    Many leaves had been reduced to skeletons.

  5. This beetle is definitely on the march through Yorkshire. It is no longer a surprise for me to see it. Today I spotted it on young alder saplings planted relatively recently in Stainburn Forest near Timble, Otley, North Yorkshire.

  6. My granddaughter and I have watched the full cycle this year on a footpath in Chorley Lancashire. The alder leaves just before they fall are like fine lace! Hoping the alder trees are not suffering too much.

  7. I found this beetle today in the water meadows along side the river at Spetisbury near Blandford, Dorset. Infesting young Alder trees. I have never seen it before

  8. I have seen this beetle in two successive years at Old Moor nature reserve between Barnsley and Doncaster. I mentioned it last year to the staff who seemed unaware of their presence.

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