Acer palmatum disease
I have returned from holiday to find my 10 yr old acer 'Garnet' covered in a white sticky mess, a bit like minute cotton wool balls, all over. What do I need to do and will it survive? Please help.
It sounds like you have either mealybugs or possibly scales, which are closely related to mealybugs and are an occasional problem on maples. One of the most common is cottony maple scale. The insect forms a cottony mass on the lower sides of branches. Scales are usually controlled with horticultural oil sprays. Neem oil is also effective. Here is more iinformation: https://www.gardeningknowhow.com/problems/pests/neem-oil-uses.htm