Githure, C.W., Zimmermann, H.G., & Hoffmann, J.H. 1999 Host specificity of biotypes of Dactylopius opuntiae (Cockerell) (Hemiptera : Dactylopiidae): prospects for biological control of Opuntia stricta (Haworth) Haworth (Cactaceae) in Africa.. African Entomology 7(1): 43-48.

Notes: Opuntia stricta (Haworth) Haworth and Opuntia ficus-indica (L.) Miller are the most prominent of the cactus weeds that have become invasive in several countries in Africa. Recent confirmation that there are at least two distinct biotypes of Dactylopius opuntiae (Cockerell), each specific to particular groups of Opuntia species, has enhanced prospects of O. stricta being controlled biologically with no threat to O. ficus-indica. The 'stricta' biotype has been used with considerable success for biological control of O. stricta in Australia for over 60 years. To corroborate the contention that the 'stricta' biotype of D. opuntiae could be used specifically to control O. stricta, with no threat to tree-like opuntias, the development and survival of the insects was monitored on several cultivars of O. ficus-indica.