Question

The prodigious spread of prickly pear (Opuntia) in South India was controlled by
A. Cochineal insect
B. Colchicine
C. DDT
D. 2,4-D

Answer 1

Hint: The biocontrol agents that are able to penetrate the cactus with their beak-like mouthparts and feed on its juices. It is a source of cochineal dye. They belong to the Coccidia family and are native to tropical and subtropical America.

Complete answer: Opuntia stricta is a native species of cactus in America. It is introduced worldwide as a popular ornamental plant. This species has escaped from cultivation and became invasive in many countries across Australia and Africa, and recently in the Mediterranean basin. Serious and large invasions have been reported in Srilanka, India, Namibia, Yemen, South Africa, Australia, Spain, Madagascar, and some North African countries. Various biological control programs have been initiated to severely reduce the spread of this species. Dactylopius coccus commonly known as cochineal insect is successfully used to control Opuntia. They have the ability to kill only small prickly pear plants. They are small-red cactus feeding scale insects. Their females are the source of cochineal dye. They usually live in colonies or clusters of individuals.
Hence, the correct option is (A)-Cochineal insect.
Note: Cochineal insects are usually grouped together on the surface of the cactus plants. They have a waxy coat that protects them from heat, cold, and predation. They have a high concentration of carminic acid which makes them economically important. They are regarded as a biocontrol agent.