It's amazing what you can find out when you've got a name! I found the info at these two links very interesting. https://nzacfactsheets.landcareresearch.co.nz/factsheet/InterestingInsects/Chinese-wax-scale---Ceroplastes-sinensis.html and http://idtools.org/id/scales/factsheet.php?name=6880 This scale is clearly very widespread and feeds on a very wide range of plants (from 50+ families), but neither of these links suggests what its natural pre-globalisation range might have been - but given the name, presumably eastern Asia.