The most famous successful example was the introduction of the gray moth, Cactoblastis cactorum, into Australia to control the prickly pear, Opuntia inermis, which was overrunning vast tracts of land.
We stand in awe of the centuried Redwoods of the Pacific coast and the twisted, giant Saguaros of the high desert, but compared to the Chaparral bush they are mere infants.