South Glamorgan,
United Kingdom 
my bay tree and japansese maple have the same ailment; white fluffy spots about 5mm accross, and 3 cm apart on teh lower part of the trunk. what is it?
8 Jul, 2010
Previous question
Scale insect, most likely - you can wash off with soapy water (preferably horticultural or insecticidal soap) and then wipe over with a cloth dipped in methylated spirits.
8 Jul, 2010