Question

Opuntia weed can be eradicated by

• A. Gambusia
• B. Cochineal insect
• C. Grass carp
• D. Both A and B

Answer 1

The correct option is B

Cochineal insect

The correct option is B

The explanation for the correct option:

1. Cochineal insects (Dactylopius spp.) cling to the outside of the host plant and (similar to how mosquitos function on people) take the plant's food and moisture out, killing it.
2. This method is used to limit the development of the Opuntia plant, often known as the prickly pear.
3. To warn off predators, cochineal insects emit a substance called carminic acid.

The explanation for the incorrect options:

Option A:

1. These gambusia fish, which are bred in ponds, wells, and smaller bodies of water, are believed to slow the spread of mosquito-borne diseases, including malaria and dengue fever.
2. Gambusia is the general name given to them because of their capacity to feed on mosquito larvae.
3. They're employed by health authorities all around the country to combat dengue fever and malaria.

Option C:

1. Triploid and diploid grass carp appear to consume similar amounts of aquatic vegetation and feed in similar ways, preferring succulent young plants.
2. The grass carp are commonly employed to reduce aquatic vegetation in ponds and lakes due to their high predilection for aquatic vegetation.

Option D:

1. Cochineal insects cling to the outside of the host plant and take the plant's food and moisture out, killing it.
2. This method is only used to limit the development of the Opuntia plant, often known as the prickly pear.
3. Hence only option A is correct.

Final Answer: Opuntia weed can be eradicated by Cochineal insect.