Euonymus are susceptible to mildew and I would spray several times during the spring and summer with a fungicide of you choice. No need to dig them up as I don't think the roots will be infected. (Baking soda solution seems to be a popular alternative spray, but I have never tried it).

Powdery mildew is associated with dryness at the roots so probably weather related this year. In a normal season it should not re-appear.

Many thanks you have saved me a lot of work. kind regards Pathumwan

There is a recommendation to remove and dispose of any infected leaves which fall to the ground - you can spray with 1 part cow's milk to 9 parts water (in the morning on a dry day) covering all leaves and stems if it reappears, repeated two weeks later, but powdery mildew is usually associated with insufficient water at the root. Which is hardly surprising this year!There is also a bicarbonate of soda treatment, details of that in this link, towards the end

https://www.gardenfocused.co.uk/fruitarticles/pest-disease/powdery-mildew.php

Not actually associated with dryness at the root, but with a lack of dew. Powdery mildew is one of the few fungi which doesn't like liquid water on the leaves, particularly when the "spores" are germinating in the early hours.

In the book I read it did say burn all shrub parts do not compost.

They just mean any shrub parts that fall or you remove , not to compost those. Burning (on a bonfire) is rarely possible these days because of local authority rules and the Co2 produced, depending on where you live, but all the old books talk about burning this sort of stuff, because most people used to burn loads of stuff from the garden without a second thought. Allotment holders still do occasionally in late autumn/winter, and probably people with large gardens and out in the countryside.

thank you for that .