Our grape vine is at least 30 years old and this is the first time I have seen scale insects on it. The species of scale is commonly found on wood plants in gardens.
Some of these images show ants in attendance. I was completely puzzled by the second image, until I viewed a stereo pair, when I could make out the posteriors of two ants facing away from us and facing the scale.
The whole range of sizes of the scales in shown in these images. The stereos are crosseye.
The ant in the last image is strangely pale but it is not a lighting effect.
Olympus EM-1 (aperture priority), Olympus 4/3 x2 TC, Olympus 4/3 50mm f2 macro, f10 or f11, hand-held.