Ragged stunt virus

• Infected plants severely stunted during early growth stages of the crop
• Leaves short and dark green with serrated edges
• Leaf blades twisted at the apex or base, which result in the spiral shape of the leaves
• Leaf edges uneven and the twisting give the leaves a ragged appearance
• Ragged portions of the leaves are yellow to yellow-brown
• Vein swellings develop on the leaf blades and sheaths
• Swellings pale yellow or white to dark brown
• Flag leaves twisted, malformed, and shortened at booting stage
• Flowering is delayed
• Incomplete panicle emergence
• Nodal branches produced at upper nodes
• Partially exserted panicles and unfilled grains
  

    The brown planthopper transmits the disease. The early instar nymphs of the insect are more efficient in transmitting the disease than older ones. Five-day-old nymphs are the most efficient transmitters. The virus is acquired within a feeding period of 24 hours.

    Viral particles are 63-65 nm in diameter and consist of five proteins. They are mostly found in phloem and gall cells. The genome consists of ten double-stranded RNA segments.
The virus is circulative and propagative in the insect vectors.

• 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.
• plouging and harrowing the field to destroy stubbles right after harvest in order to eradicate other hosts.
• Apply any one of the following to control vector BPH:

Phosphamidon 40 SL 1000 ml/ha (or) Phosalone 35 EC 1500 ml/ha (or) Carbaryl 10 D 25 kg/ha (or) (or) Acephate 75 SP 625 gm/ha (or) Chlorpyriphos 20 EC 1250 ml/ha.