Patent ID: 7737309

Claim:
A method for controlling a concentration of an aqueous agricultural chemical active ingredient solution, the method comprising: maintaining a concentration of an agricultural chemical active ingredient in water within a predetermined concentration range by including the agricultural chemical active ingredient having a saturated solubility in water at 25° C. of not less than 500 ppm in an interior space formed of a polymolecular host compound, wherein the polymolecular host compound is a tetrakisphenol compound represented by formula (I): where: X represents (CH 2 ) n or a phenylene group which may have a substituent; n represents an integer of 0 to 3; and R 1 to R 8 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms a phenyl group which may have a substituent, a halogen atom, or an alkoxyl group having 1 to 6 carbon atoms.