Question

Which of the following is not a viral disease?
(a) Red rot of sugarcane and citrus canker
(b) Leaf curl of papaya
(c) Potato leaf roll
(d) Tobacco mosaic

Answer 1

Hint: The viruses are the microorganisms that constitute genetic material either RNA or DNA which is covered by a protective layer of proteins. Viruses cause many infectious diseases in the plants. They invade the normal cells just like the kidnappers and use multiplication in those cells to produce another virus-like themselves.

Complete answer:
The most widespread infection caused by a virus is a viral disease. It causes generally the rolling of leaves and mosaic patterns on the leaves. The disease Red rot of sugarcane is caused by a fungus called Glomerella tucumanensis. This is a very severe disease found in the case of sugarcane. In this disease, the internodal tissues in the stem of the sugarcane will show reddish streaks and some white patches while the citrus canker is a bacterial disease caused by the bacterium Xanthomonas axonopodis. In this disease, the citrus fruits will show brownish-yellow spots or lesions on their fruits, stems, roots, and leaves.

Additional information:
-Leaf curl of papaya is a viral disease caused by the Papaya leaf curl virus and is transmitted through the whitefly. Its symptoms include leaf curling in an inward or outward direction, stunted growth of plants, thickening of veins, and distorted fruit development.
-Potato leaf roll is also a viral disease which is caused by the Potato leaf roll virus and is transmitted through Polerovirus. The symptoms include necrosis and chlorosis in leaves, leaf curling, stiff and hard leaves, etc.
-Tobacco mosaic is a viral disease caused by a Tobacco mosaic virus (TMV). Its symptoms include leaf curling, chlorosis, necrosis, the mosaic pattern on leaves, stunted plant growth, etc. They are transmitted through contaminated tools, hands, etc.

So, the correct answer is ‘Red rot of sugarcane and citrus canker’.

Note:
Dmitri Ivanowsky was the discoverer of viruses and the founder of virology and discovered the virus when he was investigating the cause of Tobacco Mosaic disease, which is an infection that causes tobacco leaves to discolor. Beijerinck called viruses living infectious fluids or contagium vivum fluidum. Adolf Meyer was a psychiatrist and was not related to viruses.