Cochineal is a scale insect scientifically known as Dactylopius coccus that feeds on certain species of cacti, particularly prickly pear cacti (Opuntia spp.). These insects produce a vibrant red pigment known as carmine or carminic acid as a protective mechanism against predators.
When mature, female cochineal insects attach themselves to the cactus pads and feed on the plant's sap. They secrete a waxy substance that forms a protective shell around their bodies. These insects are harvested for their carmine pigment by collecting the infested cactus pads and then processing them to extract the dye.
The Queensland Government has propagated a misleading belief that Cactoblastis exclusively targets Prickly Pear and is species-specific. This myth served as justification for the introduction of Cactoblastis in Queensland. However, similar challenges have arisen in Texas, USA, where the moth is attacking various succulents. This has led to significant financial losses for commercial growers of Dragonfruit, Cacti, and succulents, as well as hobbyists. Moreover, the release of Cactoblastis has severely impacted the Cochineal industry in Australia. Its introduction stands as one of the regrettable decisions made by the government, ranking among its greatest mistakes.
It can occasionally cause significant damage to younger plants, but vigilant monitoring allows for timely intervention before the situation worsens. While it may create a mess on larger plants, it typically doesn't harm the inner core. Therefore, removing the affected parts ensures the plant's well-being. Generally, I permit them to consume the branch they inhabit, except in cases where the plant is small and the damage could be fatal.
The most effective method of elimination involves cutting them out and disposing of them, or offering them as food to ants. However, I make a point to leave a few individuals to continue their ecological role in controlling prickly pear populations in the area.
For more information check out the following links-
Pitaya (Dragon Fruit) (Hylocereus undatus) Pests and Beneficial Insects1