Which of the following practices can help avoid European Foulbrood?

Discouraging drifting and robbing is essential in preventing European Foulbrood because these practices can facilitate the spread of the disease among colonies. Drifting occurs when bees from one colony enter another, potentially bringing pathogens with them. Robbing, where bees from one hive invade another to steal honey, can similarly introduce harmful bacteria into a healthy colony. By minimizing these activities, beekeepers can reduce the risk of transmitting the bacteria that cause European Foulbrood, ultimately helping to protect the health of their hives.

The other options, while they might have their own merits in terms of managing bee colonies, do not specifically address the primary transmission pathways for European Foulbrood as effectively as controlling drifting and robbing does. For instance, sharing equipment may share pathogens rather than mitigate their spread, and using untreated equipment or neglecting to regularly re-queen does not directly focus on the interaction between colonies that facilitates disease transmission.