Cabbage leaf help

[Forgothowtospell]

Hi does anyone know what this is on my cabbage leaf and what to do? Thanks in advance.

Cabbage white Caterpillar eggs. Squish them

Thank you. Any preventative advice?

Net them so the butterflies can’t get at them. Or be vigilant and squish the eggs, which is a lot less unpleasant than squishing half grown caterpillars. Or tolerate some losses in the interests of butterfly conservation.