Which Backpack or Handheld Sprayers are the Best?  

This depends, of course, on what type of application is desired. Handheld B&G type sprayers are often the preferred choice for spot, targeted, and/or interior pesticide applications. B&Gs are rugged, industry-standard sprayers that have withstood the test of time. Pressurized backpack sprayers are often used for exterior perimeter pest control applications along with certain applications for turf and ornamental pests. Gas powered backpack mister / blowers are typically used for larger scale exterior applications for control of insects such as mosquitoes. 

When comparing sprayer devices, consider what types of applications are desired and which insects will be targeted in order to determine which type of sprayer might be most suitable. Differences in quality can make a significant difference in the quality of the applications as well as the longevity of the sprayer itself.