Do fake wasp nests actually fool wasps?
Wasps are extremely territorial creatures. They also have great sight. Wasp colonies will send out foragers and scouts to look for uninhabited areas with food in which they can build a nest. Because wasps are so fiercely territorial, a scout wasp will generally stay away from an area with another colony already in it. 

Because of this fact fake wasps nest works!! 



Source: http://www.environmentalsociety.ca/main/wp-content/uploads/2011/05/Fact-Sheet-Wasps.pdf