Question

Given below are two statements
Statement I: Phytoplasmas are mainly spread through Psyllids
Statement II: Phytoplasmas are mainly spread through Cicadellids
In the light of above statements, choose the correct answer from the options given below:

• A. Both Statement I and Statement II are correct
• B. Both Statement I and Statement II are incorrect
• C. Statement I is correct but Statement II is incorrect
• D. Statement I is incorrect but Statement II is correct

Hint:

While psyllids and planthoppers can transmit some phytoplasmas, leafhoppers (family Cicadellidae) are the most common and economically important vectors of these pathogens.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Phytoplasmas are specialized, wall-less, phloem-limited plant pathogenic prokaryotes.
Because they lack a cell wall and cannot survive outside a host, they rely on sap-sucking insect vectors that feed on phloem sap for transmission between plants.

Step 2: Detailed Explanation:
Let us analyze the vectors responsible for transmitting phytoplasmas:
1. Statement I: Psyllids (jumping plant lice, family Psyllidae) are known to transmit certain specific phytoplasma diseases.
For example, the pear decline phytoplasma is transmitted by Cacopsylla pyri.
However, psyllids are not the primary or most common vectors for the majority of phytoplasma diseases globally.
Therefore, Statement I is incorrect as a general rule of main spread.
2. Statement II: Leafhoppers (family Cicadellidae) are the most important and diverse vectors of phytoplasmas.
The vast majority of known phytoplasmas, including sesame phyllody, potato purple top, and aster yellows, are transmitted by cicadellids.
These insects possess piercing-sucking mouthparts that penetrate deep into the phloem tissues to feed, acquiring and transmitting the pathogens in a persistent-propagative manner.
Therefore, Statement II is correct.

Step 3: Final Answer:
Statement I is incorrect but Statement II is correct.