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Context

• THE INDIAN Agricultural Research Institute (IARI) has confirmed that the mysterious disease resulting in “dwarfing” of rice plants, reported mainly from Punjab and Haryana, has been caused by the Southern Rice Black-Streaked Dwarf Virus (SRBSDV).

Background

• Southern rice black-streaked dwarf virus (SRBSDV), sometimes known as rice black-streaked dwarf virus 2 (RBSDV-2), is a novel virus threatening crop production in eastern Asia.
• It naturally infects rice, maize, sorghum and other grassy weeds
• Southern rice black-streaked dwarf virus (SRBSDV) was first reported in southern China in 2001.
• It causes a striking disease on rice and maize that leads to serious yield losses in several East Asian countries, such as China, Vietnam and Japan. Now, it has been observed in India as well.

Infection

• Southern Rice Black-Streaked Dwarf Virus (SRBSDV) is spread by the white-backed plant hopper, an insect pest, which injects it while sucking the sap from mostly young plants.
• The presence of the virus was detected both in the infected plants and the body of the vector insect, whose RNA was isolated. But the virus was not found in the seeds collected from the infected plants. The virus is specific to the phloem (plant tissues that transport sugar and organic nutrients from the leaves to other parts) and is not transmitted by seed or grain.
• Typical symptoms on rice include pronounced stunting, darkening of leaves, and white waxy or black-streaked swellings along the veins on stems.

Disease Management

• In recent years, both chemical and ecological controls have been attempted in many rice-growing areas, both in the source or overwintering areas and in migratory regions. Such pest management has certainly been proved effective in alleviating disease. In addition, to help minimize the use of pesticides or other chemicals, some practical cultivation countermeasures have been developed, including covering the seedlings with insect-proof nylon mesh or plastic film to protect them or changing the sowing date to avoid the peak of the vector migratory population, and these can provide effective control of SRBSDV and other insect-borne viral diseases.
• The development of resistant cultivars has been proved to be one of the most economical, effective and environmentally friendly strategies for control of many diseases. India can adopt these measures to control the disease.

https://indianexpress.com/article/india/iari-new-virus-behind-mystery-dwarfing-of-rice-8117779/

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