Question

Phytotoxemia include the following symtoms:
(A) Leaf curling, whitches broom
(B) Localised lesions
(C) Wilting of leaves
(D) Irregular white leaf spots

• A. A only
• B. (A), (B) and (D) only
• C. C only
• D. (A) and (D) only

Hint:

Phytotoxemia symptoms often look identical to viral diseases. The key difference is that phytotoxemia is non-systemic and stops when the insect is removed.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Phytotoxemia is the name of the pathological condition in plants caused by the toxins injected by toxicogenic insects.
Detailed Explanation:
The toxins in insect saliva can cause a variety of physiological disruptions:
1. Growth Distortions (A): Leaf curling, twisting, and "witches' broom" (abnormal brush-like growth of branches) are common because toxins can mimic or inhibit plant growth hormones.
2. Localized Lesions (B): At the point of feeding, the saliva may kill the plant cells, creating necrotic spots or lesions.
3. Pigment Changes (D): Toxins can interfere with chlorophyll production, leading to irregular white or yellow spots on the leaves.
Wilting (C) is generally a symptom of vascular diseases or water stress (though it can occur in extreme toxicosis), but the primary diagnostic symptoms of phytotoxemia are growth distortions and pigment localized damage.
Common pests causing these include aphids, leafhoppers, and some bugs.

Step 2: Final Answer:
Phytotoxemia symptoms include (A), (B), and (D).