Question

Most of the non-persistent viruses are transmitted by:

• A. Weevils
• B. Leaf beetles
• C. Carrion Beetles
• D. Aphids

Hint:

Non-persistent = "stylet-borne" viruses; Persistent = "circulative" viruses in insect vectors.

Answer 1

The Correct Option is A

Non-persistent viruses:
Don't circulate in the insect body
Don't require incubation period
Transmitted during brief probing
Aphids (option 4) account for >50% of non-persistent virus transmissions
Beetles (options 1-3) typically transmit persistent viruses

Answer 2

Reasoning from the biology of stylet-borne transmission:
Non-persistent viruses are picked up and inoculated within seconds during brief, superficial "test" probes of the plant epidermis, the virus adheres only to the tip of the piercing-sucking stylet, with no circulation, incubation or retention period involved.
Aphids show exactly this stylet-probing feeding behaviour, repeatedly sampling many plants with brief probes while searching for a suitable host, picking up and depositing virus particles at the stylet tip each time, which is why they are responsible for spreading the overwhelming majority of non-persistent plant viruses.
Weevils, leaf beetles and carrion beetles feed by chewing rather than by brief stylet probing, and beetle-transmitted viruses follow a different, far less prevalent transmission pattern.
This stylet-probing feeding mechanism is what makes Aphids the correct answer.