Paddy Yellow stem borer: Scirpophaga incertulas
Pyralidae,Lepidoptera
Distribution : The pest is widely distributed in all Asian
countries, monophagous and is a major pest on rice in India
Host range: Rice
Appearance: The female moth has bright yellowish browno Frewings with a clear single black spot and the anal endhaving tuft of yellowish hair. The male is pale yellow and the spots on the forewings are not conspicuous. Male is smallert han female.
ETL
• 1 egg masses/ m2
• 5% dead hearts - Vegetative stage
• 1% white ear - Flowering stage
Life cycle:
Eggs are laid near the tip on the upper surface of tender leaf in
small masses, covered with a buff coloured mass of hair and scales.
Single female lays 2 or 3 clusters of eggs, each having 15-80 eggs.
Eggs hatch in about 5-8 days.
Newly hatched larvae which are pale white with dark brown head and prothoracic shield.
They hang down by silk thread, get blown off to other clumpso r land on water, swim freely and get to the plants.
Larval duration is 33-41 days. Before pupation, the larvap repares an exit hole with thin webbing.
Pupation takes place inside the stem near base in a white silkenc ocoon. Moth emerges in 6-10 days
Damage symptoms :
• “Dead-heart” at vegetative stage which turns brownish, curls and
dries off
• “White ears” at heading stage with empty, partially filled grains
• Presence of egg masses near the tips of tender leaf blades
• Activity of moths in the vicinity
• Frass at the feeding site
Whitehead or dead panicles at reproductive stage (IRRI)
MANAGEMENT:-
Monophagous nature and peculiar boring habits of yellow stem borer
make control with insecticides difficult.
Cultural control
Harvesting of crop close to soil surface, ploughing or flooding the
field after harvest to kill hibernating larvae in the stubbles
Selection of varieties resistant to yellow stem borer : Swarnamukhi
(NLR 145), Pothana (WGL 22245), Varsha (RDR 355)
Mechanical control
Clipping the tips of the seedlings prior to transplantation aids in the limination of egg masses
Setting light traps or pheromone traps for monitoring the pest
Collection and elimination of egg masses
Seedling root-dip with chlorpyriphos (0.02%) @ 200 ml in 200 litres of water. Seedling root-dip is effective for 30 days in the mainf ield against stem borer, gall midge, BPH and GLH.
Chemical control
Nursery:
5 days before pulling the nursery application of carbofuran 3G @200 g/cent of nursery in a little water (seedling root-dip not required)
Foliar sprays with monocrotophos 1.6 ml/l or chlorpyriphos 2.0 ml/la t 10 and 17 DAS Main field
Foliar sprays with chlorpyriphos 2.5 ml/l or phosphamidon 2.0 ml/lo r acephate 1.5 g/l or cartap hydrochloride 2.0 g/l or chlorantraniliprole 0.4 ml/l
At panicle initiation stage: cartap hydrochloride 4 g @ 8 kg/acre,
Carbofuran 3 g @ 10 kg/acre rice
Biological control
Egg parasitoids: Trichogramma chilonis
Larval parasitoids: Goniozus indicus
Pupal parasitoids: Elasmus albopictus
Predator: carabid beetles
