Now ( first and second week in August) is the time to be on the look out for catalpa worms in Iowa. A good rain or high wind may knock them to the ground or use a ladder. I have only used them twice, and each time it was awsome fishing. Catalpa worms, in many peoples opinion, are the best catfish bait you can use, bar none. To a catfish, the juice in the worm is like blood to a shark.