Question

Which disease is caused by phytoplasma?
A. Grapevine yellow disease
B. Sandal spike
C. Grassy shoot of sugarcane
D. All of the above

Answer 1

Phytoplasmas are pathogens of agriculturally essential plants, including coconut, sugarcane and sandalwood, which cause a wide range of symptoms, ranging from mild yellowing to death.

Complete Answer:
Phytoplasms are attaching bacterial parasites of plant phloem tissue and of the insect vectors engaged in plant-to - plant transmission. Phytoplasmas were discovered in 1967 by Japanese scientists who named them mycoplasma-like organisms. Phytoplasmas are distinguished by the lack of a cell wall, a filamentous or pleomorphic form, typically less than 1μm in diameter with a very small genome.
Grapevine yellows (GY) are phytoplasma associated diseases that occur in many grape growing regions of the world. Very similar signs of GY syndrome are caused by various phytoplasmas which occur on the stems, shoots of grapevine clusters. Typical signs include discoloration and necrosis of leaf veins and leaf edges, downward curling of leaves, absence or partial lignification of shoots, stunting and necrosis of shoots, inflorescence abortion and berry shrivelling.
Spike disease caused by phytoplasma is a major disease of sandalwood. The disease is present in all main sandal-growing states of India. Spike disease is characterised by a severe reduction in leaf size, followed by stiffening and reduction in internode length.
Phytoplasma-infected sugarcane plants are proliferation of tillers, giving it a common grassy appearance, hence the term Grassy Shoot Disease. The leaves of infected plants do not contain chlorophyll and therefore look white or creamy yellow.

Thus, the correct answer is option “D”. i.e., All of the above.

Note: Phytoplasmas are most common in tropical and subtropical areas. They are spread from plant to plant by vectors (usually sap-sucking insects like leafhoppers) in which they can reproduce and survive.