Has anyone used a Defendor in a backpack sprayer? If so, did you spot treat or spray wall to wall? I won't have my Z spray until the spring but would still like to use Defendor when it cools down this fall. My question is, if it can be effective in a back pack? My sales rep was concerned about it being too sensitive for a backpack sprayer because you can't get the even coverage you can from a broadcast application on a Z spray. Any advice?