London (change)
Today 14°C / 8°C
Tomorrow 13°C / 10°C
13 messages
25/08/2013 at 15:15

I have searched the internet and found many similar beetles (rose beetle, june beetle etc)  but none so small and eating ONLY the polygonum which is generally supposed to be pest and disease free.  What are they?  They are no more than 5mm long and bright metallic emerald with black underparts.  Antennae are fairly long, flexible and made up of a string of tiny blobs when you look with a magnifier.  They do not fly away but drop to the ground and play dead till you've gone.  Is it a foreign import that likes our hot summer - is it potentially part of the answer to Japanese knotweed - or is it just something common and nasty I just haven't noticed before?

25/08/2013 at 15:22

They sound interesting. Have you got a photo?

25/08/2013 at 20:13

Yes.  I will have a go at attaching one.  This one opened its wings since it wasn't happy to be photographed so it looks a bit longer at the back than when the wings are completely stowed.  The ruler shows cms.

 

http://s4.gardenersworld.com/uploads/images/original/29895.jpg?width=512&height=324&mode=max

 

25/08/2013 at 20:31

There is a wonderful website called Whatsthatbug and, although it is based in the USA, there are lots of other creatures mentioned on it.

The nearest thing that I could see after a brief look on the website was a leaf beetle of the order Chrisomelidae.

It is great fun to look at this website as the people who run it are quite eccentric.

25/08/2013 at 21:28

Thank you.  I've had a look and it does look at lot like the dog bane beetle (although their picture gives no size).  If so, why is it here?  Anyway, I have sent the picture to them so see if I get a response.  Maybe I'll put some in a container and send them to the RHS.

25/08/2013 at 22:04

I think a photo would suffice!

27/08/2013 at 20:43

If I get any replies to my enquires hither and thither - I will let you know.

27/08/2013 at 21:30

28/08/2013 at 18:11

Do you know, I have just returned frodm a day's walking in the beautiful Derbyshire Dales and have seen no less than three of the pretty little beetles on the way. They were all on dock plants and, I don't know if the two things are linked, all the leaves of all the docks were a complete lacework pattern with only the veins remaining.

Also saw dozens of ladybirds and ladybird larvae, which was very cheering as there are very few to be found in my garden.

29/08/2013 at 10:03

Yes they are very pretty but I have to admit I disposed of hundreds of them yesteday by digging up all the polygonum and putting it on the bonfire.  I did feel sorry in a way but the plants were covered in them and, as you say, progressively turning into lace. Pleased to say one ladybird crawled out as I was digging so I rescued her and put her among the Rosa Rugosa. 

No word yet from the experts.

18/09/2013 at 22:47

I got a very full reply finally from the RHS.  It is a green dock beetle so you found them in their proper place.They have two generations between April and September and they are keen on rhubarb!  Fortunately they didn't notice mine!

19/09/2013 at 07:37

Fascinating!  Thanks for letting us know - I shall keep my eyes open for them on dock leaves. 

Lyn
19/09/2013 at 19:30

Thank you for finding out what those beetles are called, i had searched the net and could only find the small scarab.

I have found these on dock and my rhubarb was covered.

I have sprayed them with Baby Bio house plant insecicticide, they just dropped of dead instantly.

email image
13 messages