For study

1. GRASSY STUNT
VIRUS

2. Generally rice grassy stunt virus occurrence is
not widespread. The disease can become a serious
problem of limited rice growing areas when there are
brown planthopper outbreaks.
Rice grassy stunt virus affects rice crops in areas
where continuous, year-round rice growing is practiced.
The virus is transmitted between plants by insect
vectors. Nymph and adult stage plant hoppers are
common vectors for rice grassy stunt virus. The plant
hoppers need to feed on an infected plant for at least 30
minutes to pick-up the virus.
Grassy stunt virus (RGSV) is a member of the
Tenuivirus group.

3. Symptoms
 Diseased hills are severely stunted with excessive tillering
and a very upright growth habit
 Diseased hills has a grassy and rosette appearance
 Leaves short, narrow, and yellowish green with numerous
small rusty spots or patches, which form blotches
 Retention of green coloration of the leaves after application
of sufficient nitrogenous fertilizers
 Infected plants usually survive until maturity, but produce
no panicles
 The symptom develops 10-20 days after infection.

4.  severely stunted plants
 excessive tillering
 very upright plant growth
 grassy and rosette appearance of plants
 yellowish green leaves that are shorter and narrower than normal
 leaves that remain yellow even after application of sufficient
nitrogen fertilizers
 numerous small rusty spots or patches on leaves, which merge
into blotches
 leaves have a mottled appearance
 plants that fail to produce panicles

7. Identification of pathogen
 The virus exists in the vector and in the rice crop.
Brown planthopper nymphs and adults transmit it
where rice is grown year-round.
 The macropterous forms or the long winged adults of the
insect are important in spreading the disease than the short
winged forms
 They feed on the diseased plant for at least 30 minutes
to pick-up the virus. Higher infection is attained after
prolonged inoculation feeding periods of up to 24 hours.
 The availability of the vector encourages the damage.
Rice grassy stunt virus (RGSV) is a member of the
Tenuiviruses.

8. At a population density of 400−500
nymphs or 200 adults per plant.
crescent-shaped white eggs inserted
into the midrib or leaf sheath
white to brown nymphs
brown or white adults feeding near the
base of tillers

12. Management Strategies
•Avoid close planting and provide 30
cm rogue spacing at every 2.5 to 3.0 m
to reduce the pest incidence.
•There are varieties released by IRRI,
which contain genes for BPH resistance,
like IR26, IR64, IR36, IR56, and IR72.

13. THIS CAN BE DONE EITHER THROUGH THE USE OF INSECTICIDES, BROWN
PLANT HOPPER-RESISTANT VARIETIES, OR SYNCHRONIZED CROP ESTABLISHMENT.
INFECTED STUBBLE NEEDS TO BE PLOWED UNDER AFTER HARVEST TO REDUCE THE
VIRUS SOURCE.

14. • PLOUGING AND HARROWING THE FIELD TO DESTROY STUBBLES
RIGHT AFTER HARVEST IN ORDER TO ERADICATE OTHER HOSTS.