Drought has forced grasshoppers and other insects to light on anything green and lush — and that usually means something you’re growing and watering carefully. Grasshoppers have stripped the leaves off the kitchen garden thyme and cut large swaths from leaves of the citrus and apple trees on the deck.
The real problem is when they’re not eating, they’re making more grasshoppers.
The (Urban-Wildlife) Interface 
How do we irradicate them from our gardens?
Grasshoppers are very difficult to control once they’ve reached adulthood, due to their mobility. You might check with your local extension office, or local garden center for advice on using control products. Around here, they generally get smooshed or we leave them to the birds, reptiles and other predators and pathogens. We also keep the kitchen garden plants covered with vinyl screen to keep those hungry little hoppers out.