What scenario can lead to pest infestation?

Storing recyclables in paper bags by the back door can indeed lead to pest infestation. This scenario is problematic because it can create an inviting environment for pests. Paper bags, especially those containing food residues or materials that attract pests, can provide both shelter and a food source. When recyclables are left in an accessible area, especially near entry points like a back door, they become easy targets for insects and rodents looking for places to nest and feed.

In contrast, the other scenarios all involve practices that actively contribute to pest control. Cleaning up spills around garbage containers reduces food and moisture that attract pests. Sealing cracks in floors and walls and around pipes prevents pests from entering the premises, effectively acting as a barrier to infestations. Installing air curtains above doors provides a physical barrier that helps prevent pests from entering when doors are opened. These measures are all essential components of an effective integrated pest management strategy, reinforcing the importance of maintaining cleanliness and proper storage to prevent pest problems.