PESTS OF PADDY
More than 100 insect species are associated with the rice crop at one stage or the other and 20 of these are pests of major economic significance.
Yellow Stem Borer
Scirpophaga (Tryporyza) incertulas (Walker) (Lepidoptera : Pyralidae)
Distribution and Status: Afghanistan, Bangladesh, Burma, Cambodia, China, India, Sri Lanka and Indonesia.
Marks of identification:
The female moth has yellowish forewings with a black spot on each and an anal tuft of yellowish hairs at the tip of abdomen. The male is smaller and without the black spots on forewings.
Larva is pale yellowish with dark brown head.
Host plants:
Paddy, Dharo, Kodra and Chidho.
Nature of damage:
The newly hatched larva enters the leaf sheath and feeds for two to three days and bores into stem near the nodal region. The larva feeds inside the stem causing drying of the central shoot or 'dead heart' in young plant and drying of the panicle or 'white ear' in older plant.
Life history:
The female lays eggs in a mass near the tip of tender leaf blade and covers them with yellowish hairs. Egg period - 5 to 8 days, Larval period - 4 to 5 weeks, Pupation take place in to stem, Pupal
period - 8 to 10 days, Adult longevity - 2 to 6 days, Total life cycle is completed in 43 to 58 days. The hibernating larvae remains in the stems or stubble when the crop is harvested (Nov. to March).
Management:
- Stubble should be destroyed immediately after harvesting to kill the hibernating larva of SB
- Crop rotation
- Selection of resistant variety viz., Narmada, GR - 101, IR - 22, IR - 66, Gurjari, C.R. 138-928.
- Early sowing i.e. third week of Jun to first week of July.
Nursery management:
- Apply carbofuran 3% G OR Cartep hydrochloride 4% G @ 1 kg or
Neemark 15 % G @200 gm OR Phorat 10 % G @400 gm - twice, five days after sowing and five days before
uprooting the plant.
- Dipping the seedlings in the solution of chlorpyriphos 0.1 % for 30 minutes.
- Clipping the tip of seedling before transplantation helps in the elimination of egg masses.
- Install pheromone traps with Scirpo lures equidistantly in the field one month after the transplanting of the crop @ 30 traps/ha. Lure should be changed at 3 weeks interval.
-Install the light traps pheromone traps (Scirpo lure) or for monitoring the population
- Collection and destruction of egg masses or keep the egg masses in wire cage box for conservation of egg parasitoids.
- Collection and destruction of dead hearts or white ears along with larvae to minimize the incidence.
ETL: 10 dead hearts/ 20 clumps, 1 adult or 1 egg mass / 1 sq.mt.
- Granular application of Cartaphydrochloride 4 % G - 20 kg carbofuran 3 % G 25 kg/ha, First – 20 to 25 DATP and second - 15 to 20 days after first application.
Foliar spray with monocrotophos 36 % WSC 0.04% - 10 ml or quinalphos 25 EC 20 ml or triazophos 40 % EC 10 ml or cartap hydrochloride 50 % SP 0.05% 10 gm or bifenthrin 10 EC 10 ml or fipronil 5 SC 20 ml or flubendiamide 20 WG 3 gm or chlorantraniliprole 18.5 SC 3 ml in 10 liter water
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