The links below have great information to help you prevent the spread. Purchase your annuals, perennials and mulch from a reputable source; these nurseries should be fully aware of Jumping Worms. Be careful when sharing plants between gardens. I would also like to add that I have made it a routine practice to treat any new bare root daylilies that come into my garden with a 10% bleach solution (1 cup bleach to 10 cups water). I soak my daylilies for an hour or so and hose them off with water and let them soak in the water to rehydrate before planting.
Be observant -- and good luck!
Jumping Worm Information and Resources:
Video Shown is from Expedition Homestead