Rice Insect Pest Management


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(i)Stem Borers : There are different types of stem borers. Caterpillars that bore into stem cause the damage and feed internally causing the death of central shoot known as “Dead Heart”. Affected plants produce white chaffy earhead at flowering stage. Just after hatching larvae migrates between the leaf sheaths where they are protected from natural enemies and insecticidal sprays.

Management :

* Plough and destroy the stubbles after harvest, collect and destroy egg masses in nursery plants.
* Clip off the leaf tips and burn to kill eggs or larvae preventing them from carrying into the main field.

Chemical Control :

* Dip the root of seedlings before transplanting in a solution of chlorpyriphos 1 ml in 1 litre of water for four hours.
* Apply carbofuran 3G @ 20-25 kgs per hectare at 20 and 40 days after transplanting. If the pest appears spray the crop with endosulfan (20 ml) or Carbaryl (36gm) or Quinalphos (27ml) in 18 litre water.

(ii)Army Worms: A full grown caterpillar is dull green in colour with four longitudinal stripes and an orange or brown head . Caterpillars feed on the leaves and in severe infestation entire seed beds and fields are destroyed and the fields appears as if it has been grazed by animals /cattles. The larvae feed voraciously in the night and hide in the soil during the day time.

Management :

* Regular survey of crop at and before maturity. Keep the field under water through proper water management.
* Place straw beds in the fields at several locations. Collect /destroy hiding caterpillars.
* Spray the Bunds with pesticides to prevent migration of pest from one plot to another.

Chemical Control : Spray the crops with any of the chemicals as mentioned in the spray schedule under stem borers.

(iii)Rice Hispa: The insect has attained the status of major pest in bordering areas of Assam and Bangladesh . Both adults and grubs do damage. The adults are small blue green beetle with spines all over the body. The grubs enter and mine the leaf between the epidermal layers creating irregular translucent patches. The adults scrap the upper surface of the leaf blade leaving only the lower epidermis. The damaged plant parts appear as white streaks parallel to the mid ribs.

Management : Check up at the nursery stage, clip affected leaves to prevent carry over grub population. Remove weeds from the nearby fields, which serve as alternate host of the pest.

Chemical Control :

* Dip the seedlings in Chlorpyriphos (0.02 %) for 30 minutes before transplanting.
* Apply Carbofuran 3G @ 20-25 kg per hectare at 20 to 40 days after transplanting. If the pest appear spray the crop with the same chemicals as per spray schedule under stem borers.

(iv)Leaf Folders : The adult moths are brownish orange in colour 8-10 mm long with a wing span of 12-20mm. The larva infests the leaves, roll them longitudinally, live inside and feed on the green matter.

Management : Remove grasses and weeds from the nearby field which are alternate host of the pest.

Chemical Control : When Infestation is observed spray the crop with the chemicals as recommended earlier.

(v)Case Worm : Adults are 6mm long with wing span of 15mm. Slender green coloured caterpillars cut leaf blades into length of about ½” out of which they make tubular cases with which they feed. Several tubes are seen hanging from the plants. The caterpillars often drop suddenly on the surface of water and paddle along till it reaches another plants. During heavy damage, leaves are skeletonised and appear whitish in colour.

Management : Drain water from the field to flush out the insects and tubular cases floating in the field.

Chemical Control : Spray the crop with Quinalphos or Endosulphan solution @ 27ml either one of the chemicals in 18 litres of water.

(vi)Gundhi Bug : It is a major problem in upland as well as in lowland where paddy is grown continuously. The adult is about 15mm long, slender and brownish green in colour, which emits an offensive odour. Both nymphs and adults suck the sap from the developing grains by which grains becomes empty (chaffy), lower in quality and break during milling.

Management : Use pheromone traps.

Chemical Control : Dust the crop with Carbaryl 5% or Malathion 5% dust or Chlorpyriphos 2% dust @ 20kg/ha in the morning hours with dusters.
OR
Spray the crop with Monocrotophos or Endosulphan or Quinalphos @ 27ml/18litres water to reduce the population.

(vii)Plant Hopper : The adult hopper is light to dark brown in colour measuring about 3-4mm in body length. Both nymphs and adults damage the plants by sucking the sap. During the early stage of plant growth reduces height, general vigour and infested plants turn yellow and dries up. At later stages, crop dries up in patches known as hopper burn. The pest also transmits virus disease called “grassy stunt”.

Management : Drain water from the field to flush out the insects and tubular cases floating in the field.

a. Clean cultivation by timely weeding to reduce pest population.
b. Adopt spacing as recommended.
c. Use resistant varieties.

Chemical Control : Spray the crop with Quinalphos or Endosulphan solution @ 27ml either one of the chemicals in 18 litres of water.

(viii)Root Knot Nematodes : Those are tiny worms like living bodies. Causes formation of galls on the roots. It attacks the crops during early growth stages and is severe in uplands. The infected plants look stunted with orange yellow leaves and highly reduced yield.

Management :

* Use resistant varieties.
* Provide staking for perching birds.
* Seed/ Seedlings treatment to reduce field protection.
* Place straw on bunds and in fields at several locations collect/destroy hiding caterpillars.
* Check the nursery, clip off affected leaves if infestation is noticed.

Chemical Control : Apply Carbofuran Granules @ 20-25 Kg in nursery at 7 and 50 days after transplanting help control the destruction by root knot nematodes.

I.P.M Strategy for Management of Insect Pest

* Regularly check the insect pest population and its build up.
* Collect egg masses by hand and kill.
* Conserve and encourage parasites and predators.
* Use selective insecticide.
* Clean cultivation-timely weeding.
* Avoid chemical control even at minor loss. Use chemical when only needed.
* Use chemical safe to environment.
* Use balance fertilizers.
* Go for resistance and tolerance varieties.

(Source – http://megagriculture.gov.in/PUBLIC/package_of_practice/rice.aspx#manures_fertilizers)

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