That is correct, according to the product label, Prentox PBO-8 Synergist cannot be applied higher than 10 feet above the ground or crop canopy, so if the application you need to do requires application above that height limit then I would reconsider using this product. The Phytotoxicity Notice on the product states, "Prior to tank mixing, do a compatibility test using the proper proportions of pesticide, synergist and water to ensure physical compatibility of the mixture. Mix at a rate of 2 to 8 fl. oz. of this product per acre, based on the amount of active ingredient. In the absence of specific data or prior experience on growing crops and ornamentals (outdoors, in greenhouses or indoors), test tank mixes on a small sample of the plants to be treated prior to use and observe for any phytotoxic injury."