what are these and how do i get rid?

[Beans on toast Dave]

hi,

i have a garden apple tree and have just noticed loads of back dots underneath the leafs, how do i go about curing this before they hatch?

 

[R.O.S.S.I]

Wash them off with water?

 

[Cosimo]

Some sort of aphid colony like blackfly?

This may help:

https://www.rhs.org.uk/advice/profile?PID=769