Parasite problem

Lee9

I've just returned home from holiday to find one of the bushes in my garden has lost almost half of its leaves.
Initial I put it down to the heat but on closer inspection it's covered a tiny white substance.

Could anyone tell me what it is and how I treat it?

Thanks in advance. 

Lee 

herbaceous

Hi Lee9, not an expert at all but they look like sawfly larvae. Too many different sorts for different plants but someone on here will know I'm sure.

Palustris

Those are the cast off skins of aphids. You have a major infection there. The leaves may well have been eaten by something, or they have just suffered from the aphids and fallen off.

Kitty 2

Zoomed in, the small brown ones remind me of scale insects but are tiny compared to the ones I see in my garden.
Are the white things a small caterpillar @Lee9? If the white bit is soft fluff, not connected to the 'head' of the beast they could be scale insects laying eggs.

Borderline

I agree with Kitty 2, that looks like Euonymus Japonicus, and it's very common for this shrub to be under attack from scale insects. Very difficult to control to be honest and in very severe attacks, you may see yellowing of leaves and yellow spots and leaves drop off. Check the undersides and stems too.

Take a look at the link for advice.

https://www.rhs.org.uk/advice/profile?PID=798

Fire

Euonymus seem to be easily attacked by everything. Mine is attacked every summer by mildew and looks rank for most of the summer....