Whiteflies on kale

Whiteflies are on my kale!

Is there anything I can do to stop them?

I’ve read that companion planting helps – marigolds in between brassicas.

Also read that washing the kale with soapy water helps – has anyone tried this? Would I use hard soap or liquid?

The other suggestion is to add ladybirds to the kale site – maybe this is a good idea.

Would it be too late to cover with enviromesh as I assume that the leaves are already infected……

Any ideas/solution would be most appreciated!