Question

Biological control of wooly aphid is achieved by:

• A. Epiricania melanoleuca
• B. Encarsia hispida
• C. Aphelinus mali
• D. Coccinellid predators

Hint:

Associate the woolly apple aphid (Eriosoma lanigerum) directly with its primary host-specific parasitoid Aphelinus mali.
This is an outstanding, classic example of successful importation biological control in horticulture.

Answer 1

The Correct Option is C

Biological control is the method of controlling pests using other living organisms, such as predators, parasitoids, or pathogens.
Classical biological control often involves introducing a highly host-specific natural enemy from the pest's native region to manage its population in an area where it has become invasive.

Step 2: Detailed Explanation:
The woolly apple aphid (Eriosoma lanigerum) is a serious pest of apple orchards worldwide.
It feeds on the sap of twigs, branches, and roots, forming galls and secreting a dense, white, cottony wax that protects it from chemical insecticides.
To manage this pest, the chalcid wasp Aphelinus mali was introduced as a biological control agent.
Aphelinus mali is a highly specific endoparasitoid.
The adult female wasp inserts its eggs directly into the body of the woolly aphid.
The developing parasitoid larva feeds on the internal tissues of the aphid, eventually killing it.
The dead aphid's body turns into a hard, black, mummy-like shell.
The adult wasp then emerges through a circular hole cut in the back of the dead host.
This biological control agent has provided highly effective and sustainable suppression of woolly apple aphid populations globally.
Let us review the roles of the other options:
- Epiricania melanoleuca is an ectoparasitoid specifically used for the biological control of the sugarcane leafhopper (Pyrilla perpusilla).
- Encarsia hispida is a parasitic wasp used primarily to control whiteflies, such as the spiralling whitefly.
- While general Coccinellid predators (ladybird beetles) do feed on woolly aphids, they are generalist predators and are not as host-specific or consistently effective at controlling woolly aphids as Aphelinus mali.

Step 3: Final Answer:
The biological control of woolly apple aphid is specifically and successfully achieved by the parasitoid Aphelinus mali.