The Disney parks are almost obsessive about keeping the park clean. The trash cans are emptied on a regular schedule, and any spills of food are cleaned up almost immediately. Cleanliness is the best way to keep flies away.

The absence of flies and mosquitoes at Disneyland is the result of a massive, multi-layered "Pest Management Program." First, there is zero stagnant water; every body of water in the park is either constantly moving, chemically treated, or "dyed" to prevent insect breeding. A supportive peer "engineering" secret: Disney uses "Sentinel Chickens" around the property to monitor for West Nile virus; if a chicken’s blood shows antibodies, they know exactly where to increase their targeted, non-toxic spraying. Additionally, the park is designed with "Garbage Engineering"—trash cans are never more than 30 feet apart and are emptied almost constantly to eliminate food sources. They also use natural predators, such as releasing thousands of ladybugs and maintaining a "feral cat" population to hunt rodents. Finally, Disney plants "pest-repellent" flora and avoids sweet-smelling flowers near high-traffic areas, creating a "natural" barrier that keeps the park feeling like a bug-free fantasy.