You mean, without killing them? Killing them is by far the best way to prevent them from attacking. I've heard that grasshoppers and other bugs don't like garlic spray, but you might not either. If you grow your own garlic, and don't mind the smell, that might be a solution. They'd turn up their nose and go somewhere else to eat. But buying enough garlic in the store to spray on trees and large beds will be an expensive proposition. I guess you can buy garlic spray insect repellent also, but it is surprisingly pricey.

Fine netting is safe, non invasive and effective.

I use "Surround WP", a kaolin clay product that discourages (in my experience) many different kinds of pests from feeding and laying eggs.

I first started using it several years ago to discourage Japanese beetles during an especially bad year but soon realized that I didn't have a fraction of the usual culprits common to vegetable gardens.

Another big benefit is that the coating prevents sun scald and heat stress. It's commonly used in orchards and farms to protect tree fruits and tomatoes from the summer sun and heat, thus increasing the quality and yield of the crops.

It's recommended for use in organic gardening, at home and for the commercial growers.

I so agree with rhizo_1. Surround is wonderful stuff. I've also tried kaolin clay by itself and it worked too. Surround saved my tomatoes when there was a stink bug invasion that was destroying them.