Rice yellow dwarf: Candidatus phytoplasma

Symptoms:

• The infected plants are stunted and have yellowish green to whitish green leaves.
• There is excessive tillering and leaves became soft and droop slightly.
• Root growth is also reduced significantly.
• Chlorosis occurs on the leaves occasionally even spreading to the leaf sheaths.
• Streaks may also form parallel to the leaf veins.
• If plants are infected early they usually die before maturity and even if they do survive no panicles are produced or only a small number with no grains.

Mode of spread: 

• It is transmitted by Nephotettix virescens and N. nigropictus with a latent period of 25-30 days.
• It survives on several grass weeds.

Management:

• Deep ploughing during summer and burning of stubbles.
• Rice varieties like IR62 and IR64 are resistant to the disease.
• The management practices followed for Rice Tungro Disease(RTD) may be adopted for this disease also.
• Avoiding early planted rice will prevent an increase in vector density and proportion of virus acquired vectors.
• Planting fallow rice fields with non vector hosts, ploughing fallow paddy fields and late-planting,
  synchronous planting or avoiding an overlap of early and late planted rice crops.
• Remove weed hosts periodically. .
• Crop rotation .
• The vegetation on the bunds should also be sprayed with the insecticides.
• Chemical Method: Vector control with any one of the following insecticides .
• Thiamethoxam 25 WDG 40g/acre (or) Imidacloprid 17.8 SL 40 ml/acre spray at 15 and 30 days after transplanting .