* バッタ (batta): This is the most common and general word for grasshopper. While it often includes locusts, it's not specific to them. If you're talking about locusts in a general sense, バッタ is acceptable, but it might not convey the swarm aspect.
* イナゴ (inago): This refers to a specific type of smaller locust, often edible. It's not a suitable translation if you're talking about large locust swarms causing damage.
Therefore, the best word choice depends on what kind of locust and the context. If you need to be precise, you might need to add more descriptive words. For a swarm of destructive locusts, you might say something like 大量のバッタの大群 (tairyou no batta no daigun) - a huge swarm of grasshoppers.