Diatomaceous Earth (DE)
It’s easy to locate DE in garden centers and online, and is fairly inexpensive.
Here’s how it works: The diatoms have tiny sharp edges that cut into an insect’s skin, causing the insect to dehydrate and die. We humans cannot feel the sharp edges so it’s safe to handle in that regard. However, you do NOT want to breathe in the diatomaceous earth!
In order to do that, I sprinkle a layer of DE around the base of a plant stem, such as a cucumber, melon, broccoli or kale seedling, and it works great at keeping the above critters from crossing it to get to the tender stems.