Strange growth on my grapevine...

[GrapeGrower]

I was wondering if anyone knew about this strange growth I get over my vines. They are small brown shells that appear on the stem (old wood only) they look like some kind of shelled beetle but can't work out if they are an insect or something the vine produces itself. If you squeeze them they are filled with a yellowish liquid, although sometimes they have dried out and contain a white dust only. They have been on the vines for several seasons and don't seem to be doing any harm. Pictures below:

[GrapeGrower]

Think I just answered my own question after another google search - brown scale, a sap sucking insect! Best get squashing

Brown scale / RHS Gardening Advice

[FB.]

Yes, probably scale insects.
Where natural predators are absent (such as green houses in particular), or on stressed plants (are you watering or feeding enough in summer?) they can be a problem.
I regularly find them on my various fruit trees/bushes, but I just ignore them.

[Pumpkin Becki]

Definitely scale insect you've got there GrapeGrower. I like to squish any I see to, try and keep the population down...but I'm a bit gross like that