pests (?) on plants - any gardners here??

[zimu]

image 1
image 2 (best pic)
image 3
image 4

these things are heavily growing (as can be seen by image 4) on some new shoots from a tree that had been cut down ages ago.

the green ones are even weirder - can't tell if they're giving birth to the dark things, or eating them!

weird thing- they're not harming the plant. plant is growing as it should, no dead leaves or anything. they keep migrating up and down the plant and leave no signs of having been there before - so they move up the plant and the plant below is totally fine.

any idea what they are? trying to figure out if they're aphids, and if so are they actually damaging the shoots in a way we can't see?

 

[Bryophyte]

Not sure what the big green ones are (possibly some kind of scale insect), but the black ones are almost certainly aphids. You *will* be seeing damage from them at that population level. Use a hose to wash them off, then you could spray the area with a *dilute* solution of liquid dishsoap if you want. Repeat as necessary.

 

[BrownTown]

aphids, they bad. Get some ladybugs.

 

[DrPizza]

Seconded on spraying with a solution of water and dishsoap. If you really mean business, you can go buy some malathion and spray with that.