What it does

Rice grassy stunt virus reduces yields by inhibiting panicle production.

Why and where it occurs

Rice grassy stunt virus affects rice crops in areas where continuous all-year around rice growing is practiced.

The virus is transmitted between plants by insect vectors. The vectors for rice grassy stunt virus can be plant hoppers at nymph and adult stages. The plant hoppers need to feed on a diseases plant for at least 30 minutes to pick-up the virus.

Plants off all growth stages can be infected. At tillering plants are most vulnerable to rice grassy stunt virus infection. Rice grassy stunt virus symptoms develop 10-12 days after infection. The virus is not transmitted via the brown planthopper eggs. Infected stubble and volunteer rice are sources of rice grassy stunt virus.

How to identify

To identify hills of Rice Grassy Stunt Virus infected plants check for the following symptoms:

• 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 blotches have a mottled appearance
• plants that fail to produce panicles

The stunting and excessive tillering symptoms of rice grassy stunt can be confused for symptoms of rice yellow dwarf and rice dwarf virus. To confirm Rice Grassy Stunt, check for grassy or rosette appearance of plants and prominent rusty spots on the leaves.

How to manage

To control rice grassy stunt virus the brown planthopper vectors need to be controlled. This can be done either through the use of insecticides, brown plant hopper resistant varieties, or synchronized crop establishment. Infected stubble need to be ploughed- under after harvest to reduce the virus source.

Learn more

View full fact sheet:
Grassy stunton IRRI Rice Knowledge Bank