Jepson, F.P. 1930 Present position in regard to the control of prickly-pear (Opuntia dellenii, Haw) in Ceylon by the introduced cochineal insect Dactylopius tomentosus Lamk.. Tropical Agriculture 75: 63-72.

Notes: The history of biological control of this weed by C. tomentosus is discussed. Previously, the inability of the established cochineal insect, Dactylopius indicus, to exercise any controlling influence on O. dillenii in the northern province was one factor which led to the introduction of D. tomentosus into Ceylon in 1924.