[hammers07]

the other night i was down my allotment and noticed my rhubarb leaves covered with  bugs (about 20 of them ). They were about 1/2 inch long and 1/4 inch wide. greyish/light brown in colour (looked a bit like a beetle but squarer and flatter) Cannot find out what they were or if they are harmful to plants. Anyone any ideas or know of a good internet site where I may be able to identify them.

 :?:

[WG.]

www.whatsthatbug.com

Sounds a bit like a thrip from your description so you could Google Images for that

[hammers07]

bigger than a thrip may be a dock bug - still investigating

[WG.]

Okay be sure to post and tell us what you find out.  Did you already make them squarer and flatter than when you found them?  

[Smudgeboy]

I've just Google Imaged "Dock Bug" and it's EXACTLY what I've got on my rhubarb leaves.

Googling on the name throws this up:

Dock Leaf Bug - Coreus Marginatus (also known as Brown Squash Bug)

The Dock Leaf Bug is a very common species in the British Isles and parts of Northern America reaching a length of 12-15 mm (0.5-0.6in). Found on many flowers both in the garden and open grassy areas, often in small groups of both adults and larvae. It does not have the side stripes seen in other Shield Bug species and it's shoulders are more rounded. It has two small distinctive pointers in the front of the head between the antennae which have dark tips, whilst those of the superficially similar Arma custos (not a Uk species) are light tipped. Their respective feeding habits also differ, the Dock Leaf Bug being vegetarian feeding on plants and fruit, whilst Arma custos predates weevils.

And this:

You'll find it on many flowers in the garden, often in small groups, comprised of both adults and larvae. Because it hibernates in all life stages, it can be seen almost all year around. Hibernating specimens often are a bit darker in colour. This species loves flying. When threatened it spreads its stinking poison around and it produces a lot of the stuff. Should your skin make contact with it, it turns brown. And it will stay that way for a while, for it is very hard to wash off this poison.

Now I've gone plunging into my rhubarb to harvest it many a time - so far my skin's stayed resolutely non-brown, the Dock Leaf Bugs on my plot seem to prefer running away!

And they don't seem to have done any damage to my rhubarb - if they're nibbling the leaves, it's only little nibbles - and it's not like I'm gonna eat the leaves!

[Aunt Sally]

Dock Bug

[WG.]

Wow - looks like the stink bugs my BIL gets on his citrus trees in Ozzie

[hammers07]

yes i have been down tonigt and they definately look like dock bugs although one had half a red body at tail end (perhaps  the female).

they are part of a family of bugs known as shield bugs of which incidently the stink bugs belong. there are apparently 40 species of shield bug in the uk.

by the way how do you include images in your posts .

[Aunt Sally]

by the way how do you include images in your posts .

 This will tell you:

http://www.chat.allotment-garden.org/viewtopic.php?p=32816#32816