Abstract: A pulsating release composition comprising natural microspheres, such as pollen grains or spores, into which are loaded a biologically active is subsequently releasable therefrom in a predetermined location in or on a plant or animal in a series (generally 3 or more) of pulses. In one preferred embodiment, the composition comprises a group of substantially similar loaded micropheres coated with multiple barrier layers alternating with multiple active substance layers in a concentric onion-like structure, the barrier layers being slowly soluble to delay release of active substance from the underlying layer thereof until after the pulse of active substance provided by the overlying layer has subsided.