The Insecto Wasp Traps are rather versatile traps that can be used on a flat surface or may be suspended from a bush or tree, or post and hook.
These traps do come with liquid bait.
Can also be baited with beer, fruit juice, sugar solution or water and honey. Adding a few drops of detergent can help stop escapees!!!
Place in a quiet sunny area if possible, away from where people are congregating in order that wasps are not attracted to where you don't really want them.
You will probably not clear a wasp problem with trapping but you should be able to strategically place the traps so that any stray wasps are attrected to the traps, rather than where you are having a barbecue!!