Question

Which one of the following agents causes the necrotic ring spot disease in stone fruits?

• A. Fungi
• B. Bacteria
• C. Virus
• D. Nematodes

Hint:

When studying plant diseases, it is crucial to identify the pathogen type, whether it's a virus, bacterium, fungus, or nematode, as treatment methods and prevention strategies vary accordingly.

Answer 1

The Correct Option is C

Necrotic ring spot disease, affecting stone fruits like cherries, peaches, and apricots, is caused by a viral pathogen. Specifically, the necrotic ring spot virus (NRSV) is responsible for this disease. It is transmitted through infected plant material and can cause significant damage to fruit trees by inducing characteristic symptoms like ring-shaped lesions on leaves and fruits. Since this disease is viral, it does not result from fungi, bacteria, or nematodes, making option (C) the correct choice.
- (A): Fungi can cause a variety of plant diseases, but they are not responsible for necrotic ring spot disease. Fungal diseases in plants include powdery mildew, rusts, and blights, but necrotic ring spot is caused by a virus. Therefore, statement (A) is incorrect.
- (B): Bacteria cause diseases like bacterial leaf spot, bacterial wilt, and crown gall, but they are not the cause of necrotic ring spot disease in stone fruits. Hence, statement (B) is incorrect.
- (D): Nematodes are parasitic worms that affect plant roots, causing diseases like root knot nematode infection, but they do not cause necrotic ring spot disease. Thus, statement (D) is also incorrect.
Therefore, the correct answer is (C), as necrotic ring spot disease is caused by a virus.