Longan plant - what are these things

I have longan plants with some black things stayed on leaves and the stem. Only on longan plants not on other fruit plants.

 

I've never grown Longan, but how about Black Scale? Parasasseta nigra.



https://en.wikipedia.org/wiki/Parasaissetia_nigra

The other question is, what can you do about it? Does Australia have agricultural extension agents?

This webpage has some recommendations-

https://insectsandorganicgardening.com.au/all_insects/black-scale/

 

Thanks