Question

Non persistant, semi-persistent and persistent type of transmission is common in:

• A. Aphids
• B. Thrips
• C. Flea beetles
• D. Grasshoppers

Hint:

Aphids are the most versatile vectors of plant viruses. They are the only group capable of transmitting viruses through all three main pathways: non-persistent, semi-persistent, and persistent.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Different groups of insect vectors have evolved distinct relationships with the plant viruses they transmit.
The main vector groups include aphids, whiteflies, leafhoppers, thrips, and beetles.
Among these, some groups are highly versatile, capable of transmitting different viruses through different pathways.

Step 2: Detailed Explanation:
Aphids (family Aphididae) are the most important and versatile group of plant virus vectors, transmitting over 50% of all insect-vectored plant viruses.
Depending on the virus species, aphids can transmit viruses through three major pathways:
1. Non-persistent (stylet-borne) transmission: The virus adheres to the mouthparts during brief probes and is transmitted immediately (e.g., Potyviruses, Cucumoviruses).
2. Semi-persistent (foregut-borne) transmission: The virus binds to the cuticular lining of the foregut, requiring longer feeding times to acquire and transmit, with the vector remaining infective for days (e.g., Closteroviruses).
3. Persistent (circulative/propagative) transmission: The virus is ingested, passes through the hemolymph to the salivary glands, and is secreted during feeding, with the vector remaining infective for its entire life (e.g., Luteoviruses).
No other vector group (such as thrips, beetles, or grasshoppers) exhibits this complete range of transmission mechanisms across different virus families.
Therefore, aphids are the correct choice.

Step 3: Final Answer
The group of vectors in which non-persistent, semi-persistent, and persistent transmission are all common is aphids.