Alison James, Simon’s Town
I read with horror the suggestion that cochineal insects should be poisoned if they occur on cacti, specifically the prickly pear (“What to do about cochineal on cacti and prickly pear plants,” Echo July 15).
These insects are very beneficial and are used by the City of Cape Town as a biological control for these invasive plants. There is no place for an opuntia cactus on the Cape Peninsula, or indeed South Africa. They are all classed as Category 1 invaders, meaning that they must be removed and destroyed. No trade of these plants is allowed.
Here in Simon’s Town the lanes criss-crossing the upper and lower sections were full of very prickly stands of opuntia plants. They have largely disappeared now thanks to the work of the cochineal beetles, and what interesting insects they are. If you get under their white cover, their body sap is a beautiful carmine colour which is still farmed in Peru to this day. The dye is considered far superior to any artificial one. My advice would be to spread the beetles as much as possible so that all the prickly pears and their close family are obliterated.