Fusilade or Ornamec have a very narrow safety margin when applied to zoysia. When the label says 4 oz per acre, they mean it. If you are applying it solo, without triclopyr to safen it, it is even hotter. A zoysia lawn not on irrigation and thatchy because it is not cut with a reel is even more sensitive. Spot spraying through your normal backpack or hand sprayer with the stock adjustable nozzle is capable of applying an 8x overdose very easily. Let me explain: If someone adds the suggested rate to treat 1000 sq ft to a gallon and dispenses it through a backpack sprayer, he can apply up to 8 gallons of solution to 1000 sq ft. Even if the error applies 3 gallons or 4 gallons to 1000 sq ft, that is still too much. Fluzafop is to be applied at a set dosage per area covered. If you only covered 100 or so sq ft with a solution intended to treat 1000 sq ft. There will be a problem. An 8 x overage is the rate to remove all grasses from areas intended to be shrubs or ground covers. My idea of a "spot treatment" consists of a fixed output AI nozzle on the end of a wand fitted with a regulator to monitor and limit pressure. This apparatus is used by triggering the wand when walking past a patch of weeds at approximately 2 MPH. The nozzle and pressure is match to apply the equivalent of 1 gallon per 1000 sq ft.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety.
Benjamin Franklin 1775
Sell not virtue to purchase wealth, nor Liberty to purchase power.
Benjamin Franklin Poor Richard's Almanac1738