Vector control treatments conducted by the U.S. Air Force Reserve (USAFR) are only a request. The USAFR has the ability cancel or change their plans with little prior notice. Spray requests are scheduled 2 years in advance. This makes targeting their arrival date very difficult. Some years all the pieces come together and others it does not. Additionally, there are several state and federal regulations that must be addressed before they are able to spray, and when the regulatory landscape changes, USAFR sprays may be canceled. Williston Vector Control actively works with the USAFR to anticipate these changes, but it can take months before a resolution is found.
The USAFR only sprays a small proportion of the total annual spray acreages that the Williston Vector Control District does. The rest is treated through an aerial contractor using much smaller and more versatile aircraft.