Question

An insect whose feeding produces symtoms of disease is said to be

• A. Phytogenic
• B. Toxicogenic
• C. Allogenic
• D. Pyrogenic

Hint:

Toxicogenic = Toxin producer. The insect itself is the cause of the pathology, not a virus it is carrying.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Sometimes insect damage is not just about the tissue they remove. It is about the chemicals they inject into the plant.
Detailed Explanation:
When an insect feeds, it injects saliva into the plant tissue.
In some insects, this saliva contains potent toxins or enzymes that interfere with the plant's normal physiology.
The resulting symptoms—such as yellowing (chlorosis), stunting, leaf curling, or gall formation—look exactly like a viral or bacterial disease.
An insect that causes such disease-like symptoms through its own salivary toxins is called a "toxicogenic" insect.
A classic example is "Hopper burn" caused by leafhoppers (Empoasca spp.). The insect's saliva blocks the movement of nutrients in the plant's phloem, leading to the yellowing and drying of leaves.
This is different from an insect being a "vector" of a virus. In toxicogenesis, if you remove the insect, the symptoms stop appearing in new growth.

Step 2: Final Answer:
Insects whose feeding induces disease-like states are called toxicogenic.