Was doing a quick check on my Pyracantha today and noticed some small mites on the underside of some leaves. They are a clearly greeny yellow colour (if that makes any sense) and seem to be in groups underneath some of the leaves.
Unsure if this is unrelated but I have been having random leaves turn yellow and brown before dropping (not many but some) for a couple of months now and just thought it was natural, now I'm thinking this may be the cause?


After a quick search I'm thinking they could be the Greenfly Aphids but unsure? Just wondering if what I have are a detrimental pest or harmless? Also apart from my thumb how best do I nuke them into the ice ages

Any help will be greatly appreciated.
Cheers,
Pearcy.