Yes. Lats can be hard to train. Pull ups are probably most effective. The key is to really focus on your lats during these excercises. Most people struggle doing pull ups and use their arms/shoulders too much. Relax (I know this sounds stupid :P) your grip and use your arms simply as suspension. Get all your power from your back and VISUALIZE those lats contracting. Sounds like deep vague **** I know. But trust me, try it! It takes time to master though.
"Knowledge is the fuel. Training is the spark"