Black marks on cactus - Is this scale or something else?
I have a couple of cactus which have these black "marks". I first thought they were on account of sun burn - but they have grown / spread a bit in the last couple of months. (Photo attached) I manually prised them out using a toothpick. They come off quite easily though a fleshy impact in the cactus is visible.
They are not flat and appear to have a kind of "hook" into the cactus to feed off it. (Photo attached)
Is this scale or some other pest? Will it jump to other cactus. Other than manual removal, what other remedies would you recommend.
Many thanks for your assistance?