When Walt Disney first began to develop his plan for Walt Disney World, he wanted to buy enough land that he would have complete control over the space. He found the perfect location near Orlando, Florida. In many ways it was the perfect place to put a massive theme park along with all the other ideas Disney had planned. The only problem was, the land was essentially a massive swamp. So then, why isn't Walt Disney World full of mosquitoes?
The short answer, of course, is that the Walt Disney World Resort has just as many mosquitoes as any place else in Florida, which is a lot. The difference is, that the Reedy Creek Improvement District, the municipality that governs Walt Disney World, goes to great lengths to keep the mosquito population under control in order to make sure that guests have a positive experience that isn't ruined by bugs, or the diseases they can potentially carry.
In the mid-1960's Walt Disney hired Retired Army Major General William E. "Joe" Potter, who had previously worked on the Panama Canal project for his expertise in dealing with mosquitoes. Potter knew that stagnant water was where the insects laid their eggs, and that's why he oversaw the construction of ditches that would remove any water before it had a chance to pool. These took on the nickname "Joe's ditches." Even water in the park that appears to be staying still is always moving. Buildings on the property have their roofs constructed so that rain water always runs completely off and never leaves a pool of water. Even plants that might leave standing water on their leaves are avoided.
The most obvious way to stop insects is with insecticide, and to be sure, Walt Disney World uses insecticide, but spraying the entire Walt Disney World property would be time consuming, expensive, and incredibly inefficient. This is why, the park maintains dozens of traps all over the property which use carbon dioxide to lure in and trap mosquitoes. Again, the goal isn't to trap all the bugs. Rather, the trapped mosquitoes are frozen and analyzed. This reveals their species, their concentration, and other details that allow Reedy Creek to know how best to deal with them.
Animals are a big way to keep insects under control. Natural mosquito predators can be found all over Walt Disney World, but you'll also find chickens. Yes, chickens. Walt Disney World keeps multiple coops of what are called "sentinel chickens" at various places on property. The sole job of these chickens is to be bitten by mosquitoes. Chickens can become carriers for the various viruses that mosquitoes can carry, but they rarely become sick because of them. The blood of the chickens is regularly analyzed to see if area mosquitoes are carrying anything dangerous, such as West Nile virus.
With the combined data from the traps and the chickens, now Reedy Creek Improvement District knows where on the property is in the greatest need of mosquito population control and the best way to provide that. Insecticide is sprayed on the property twice a day from a fleet of trucks, once early in the morning and once in the evening, the times when mosquitoes are most prevalent, in order to catch as many as possible. The park also sprays with mosquito growth regulators, which reduce the lifespan of the insects.
These methods aren't entirely perfect, of course, complete mosquito eradication is essentially impossible. Some places on property, like the Fort Wilderness campground, where guests are frequently outdoors, don't get sprayed as often to avoid disrupting the guest experience. Still, the resort does a remarkably good job with mosquito control. You'd never know the place you were standing was the middle of a swamp 50 years ago.