Prickly pear weed has been effectively controlled by

Answer: Option C

Prickly pear weed has been effectively controlled by Dactylopious tomentosus.
Prickly pear is a general term used to describe the Opuntia species, members of the Cactaceae family. Native to the Americas, prickly pear is a spiny, drought-resistant succulent that rapidly invades pastures and natural areas and overwhelms other vegetation.
Dactylopius tomentosus is a cochineal insect whose host range is restricted to Cylindropuntia species. This insect has been utilized successfully for biological control.