Pests destroying kale

Question

Caterpillars about 1/2 inch when grown. Live in groups under kale leaves, destroying them. They are bkack, yellow and white stripes. Not green.

What are they and hiw dovi orevent them coming back next year.

Killed 4 of 6 kales and most if the broccoli before the second cutting.

Answer 1

This is terrible but very common. Here is a link to explain what they are and how to keep them away: https://www.gardeningknowhow.com/plant-problems/pests/insects/prevent-caterpillars.htm