Netting will keep them away. Birds eat grasshoppers. So do wasps. Other preying insects and animals. Create habitat. Live within nature not despite it. Poisons should be an extreme last resort and then only minimally in my opinion. There are some companion planting things you can do and other organic methods but in a plague there is not much. Unless you like to eat grasshoppers. They are good stir fried apparently;-)

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The secret is the soil.