Cabbage Problem

[Mondo]

Hi
Can any one tell me what the white blister underneath my cabbages is and what to do about them. All the plot holders round me have given me 20 different reasons. I hope I have managed to attach a photo
Mondo

[Two_Sheds]

whitefly

bet ya

[rustylady]

Have a look underneath the leaf.

[zazen999]

Whitefly. Deffo.

[gojiberry]

It looks like the remains of cabbage white eggs, it's obvious the eggs aren't there now but may well have been eaten by birds.

Ian

[Jax]

looks like whitefly, I have tonnes of them

[Suky]

I go with whitefly too. I have them on my brassicas.

[OllieMartin]

If it's Whitefly, my understanding is that it would be a greyish-green sooty mould that develops as a result of the sticky honeydew secreted by the pests.
This doesn't look mouldy so wouldn't that mean it was something that had eaten the underside such as cabbage white hatchlings?

[Two_Sheds]

Not always Ollie

[Mondo]

Thanks all
I am treating as whitefly and removing the infected leaves