To avoid the introduction of pests, quarantine and treat all newly acquired Haworthias before bringing them into the collection.
For a new plant, clean as much of the growing medium out of the roots and completely discard it. Some roots may be torn off but the plant will be fine. Treat the plant with potassium fatty acids soaking and then hydrogen peroxide soaking, and rinse after each soaking round. This kills any pests and fungus. Hydrogen peroxide also promotes faster healing of any damaged roots. Let the plant dry out in a shaded place before planting it in a fresh growing medium, and prioritize the application of Imidacloprid in the next waterings.
After potting, wait for ~2 days before the first watering so that any small wounds on the roots can heal. Keep putting the plant in the shaded place for the next ~2 weeks. This helps the plant establish the roots in the growing medium, because strong sunlights move auxins to the top part of a plant and discourage root growth.