a method and apparatus for dispensing pheromones , semiochemicals , and other materials that can control the behavior or physiology of insects and other pests are described . the dispensers use electronic dispensing technology such as that used in ink jet printing . the units have a self - containing reservoir for the to - be - dispensed chemical , and they are capable of being activated to dispense by an electromagnetic signal from a broadcasting controller unit . picoliter volumes of pheromones and semiochemicals can be dispensed in drop - on - demand mode . the units for dispensing shall be powered by battery and / or solar energy for hands - off operation in remote sites . the units may also have weather monitoring devices , and such climactic information can be transmitted to central receiving stations and / or used locally in the agjet device to control chemical dispensing .