Cochineal insects have proved very useful for

Cochineal insects have proved very useful for Cactus prevention.
Cochineal insects are soft-bodied, flat, oval-shaped scale insects. The females, wingless and about 5 mm (0.20 in) long, cluster on cactus pads.
They penetrate the cactus with their beak-like mouthparts and feed on its juices, remaining immobile unless alarmed. Male nymphs feed on the cactus until they reach sexual maturity.