Friend or foe?

My mature Acer Japonicum has lots of what look like pupae attached to the trunks, covered in a white fuzz (highly scientific description!). Are these going to produce good things or cause trouble? I'd welcome your thoughts please.

 

Looks like scale insects...get rid

 

Thank you @flounder!

 

Rub with a soft wet toothbrush. If that doesn't work, dip the brush in alcohol. A good use for that bottle of tequila that's been languishing in the back of the cupboard for countless Christmases. failing that, white spirit or rubbing alcohol.

 

I agree. They are currently laying eggs, protected by the white fluff. Once the eggs hatch, they'll become 'crawlers', which are highly mobile and will run all over the tree until they find a place to settle and become the immobile adult form you see there.

 

Thank you @BB3 and @BobTG, that will be the first gardening job tomorrow! I’ve got some white spirit somewhere, but no raw alcohol worth wasting!

 

The gentle rubbing is the key as they often survive spraying due to their shell like covers.

 

Not sure I would use white spirt, its greasy, meths or surgical spirit which would be my choice on mealy bugs.
Even if this is scale.

 

Come to think of it, I used meths on my fig tree. I quite like the smell

 

I've never understood why White spirit is called a spirit, its closer to paraffin IMO, and doesn't evaporate like alcohol does.

 

I do too @BB3, it reminds me of the spirit burner in a chemistry set and litmus paper!

 

We never really get scale insect here - I've certainly never seen it on any plant in any garden I've had, but I'm surprised at hearing white spirit described as greasy @pete. I often use it for all sorts of things, as well as paint removal on brushes, but I don't find it greasy at all.
I love the smell too - and meths....

 

Have you ever got white spirt on your hands it doesn't evaporate like meths which is a form of alcohol.
Exactly, as you say, it's used for cleaning oil based paint from brushes, it's a solvent.

I'm not a chemist but there is a difference

 

I saw it for the first time here last year @fairygirl. I don’t find white spirit greasy either, just difficult to get the smell off your hands!

 

I must be weird - I don't mind having the smell of it on my hands at all!