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Insect Pest Management in Rice Crop for a Bumper Harvest

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Insect Pest Management in Rice Crop for a Bumper Harvest

Insect Pest Management in Rice Crop for a Bumper Harvest;

Introduction;

Rice (Oryza sp.) is the major staple food of over half of the World’s population. Rice is consumed by more than 2 billion people across the globe for their daily dietary requirements.


The warm and humid environment under which rice is grown is very conducive to the proliferation of insects. Heavily fertilized, high tillering varieties and the practice of multi-cropping rice throughout the year are more inducive to the buildup of pest populations. On average rice yield loss due to various insect pests was estimated to be 31.5% in Asia and Pests are one of  the major reasons for the yield losses across India

 Various factors that influence the production losses are as follows;

a) Pest Causes = up to 33 % losses in production
a) Pest weed causes =  up to 12.5 % losses in production
b) Insect Causes =  up to 9.5 % losses in production 
c) Disease = up to 6.5% losses in production 
d) Other pests Causes = up to 4.5 % losses in production 
Therefore, minimizing pest losses can be the most important approach to increased productivity. 
As the rice crop is attacked by a large number of insect pests right from the nursery till the harvest of the crop. A brief description of the major insect pest, the nature of the damage, and appropriate control measures are given below:

1)  Rice Stem Borer; (Scirpophaga incertulas)

Insect Pest Management in Rice Crop for a Bumper Harvest

1) Damage caused by the larva of this insect results in a ‘Dead heart’ and “White head’.

2) Both types of damages resulting from the feeding of larvae within the stem. 
3) They bore and feed inside the stem. 
4) They cut the growing parts of the plant from the base causing the plant to die. 
5)The drying of the growing part of the plant is known as the ‘dead heart’. 
6) The dead heart is created in the early life of the plant before flowering and Whitehead occurs at flowering resulting in drying of the entire panicle. 
9)Moths may be seen flying around or floating on water in the field.

Control Measures;
1) Use pheromone traps with 5 mg lure @ 8 traps/ha for pest monitoring or 20 traps/ha for direct control through mass trapping. Replace lures at 25 to 30 days intervals during the crop period. 
2) Adopt clean cultivation practices and the destruction of stubbles.
3)  Clipping of rice plant leaf tips of the seedlings at the time of transplanting it will help in the destruction of egg masses.
4) Survey the field and if 5 % or more dead hearts are seen then immediate spraying is required
5) Apply Cartap 4G granules at the rate of 25 kg per hectare or Fipronil 0.3 G @ 25 kg/ha or Chlorpyriphos 10 G @ 10 kg/ha
6) Apply these granules at 20-25 days and again at 50-60 days after transplanting.
7) Inundative release of egg parasitoid, Trichogramma japonicum 5 to 6 times @ 100,000 adults/ha starting from 15 days after transplanting.

2) Gall Midge (Orseolia oryzae);

Insect Pest Management in Rice Crop for a Bumper Harvest

1) In midge-affected plants, regular tillers are transformed into a tubular gall resembling the leaf of an onion.

2) These are known onion Leaf 
3) This is a sucking type of insect and sometimes causes serious damage to the growing crop 
4) Tilters that have galls do not produce panicles
Control Measures;
If there are 5 % or more affected tillers per square mere adopt the same measures as suggested for the control of stem borer.

3) Rice Hispa (Dicladispa armigera) ;

Insect Pest Management in Rice Crop for a Bumper Harvest

The adults of rice hispa insects scrap on the epidermis or upper surface of the leaf blade, leaving only the lower epidermis the damaged areas can be seen with white streaks parallel to the midrib. Grubs mine between two epidermal layers producing irregular longitudinal white mines
Control Measures
It can be controlled by the spraying of insecticides; like; Triazophos 40 EC @ 400 ml/ha or Phosalone 35 EC @ 850 ml/ha or Chlorpyriphos 20 EC @ 1,500 ml/ha or Quinalphos 25 EC @ 1,200 ml/ha or Ethofenprox 10 EC @ 450 ml/ha or Fipronil 5 SC @ 600 ml/ha


4) Leaf Roller ; (Cnaphalocrocis mainsails / Marasmia patnalis)

Insect Pest Management in Rice Crop for a Bumper Harvest

1) Caterpillars of this pest cause damage by folding the leaf blades into tubular structures and feeding on the green leaf tissues within these structures.

2) Usually only one caterpillar is found within a fold. 
3) The larvas feed within this portion of the leaf causing typical white streaks by consuming all but the epidermis of the inside of the leaf Pupation occurs within the rolled portion.
Control Measures
1) one damaged leaf is seen in each hill, protect the crop by spraying Phosalone 35 EC 1500 ml/ha or Chlorpyriphos 20 EC 1250 ml/ha or Carbaryl 50 WP 1.0 kg/ha or Acephate 75 % SP 666-1000 ml/ha or Chlorantraniliprole 18.5% SC 150 g/ha or Chlorantraniliprole 0.4% G 10 kg/ha or ronil 80%WG 50-62.5 g/ha or Flubendiamide 39.35% M/M SC 50 g/ha
2) Inundative release of egg parasitoid, Trichogramma chilonis five to six times @ 100,000 adults/ha starting from 15 days after transplanting
3) Avoid excessive use of  nitrogenous fertilizers
4) Keep the bunds clean

5) Swarming Caterpillar; (Spodoptera mauritia )

Insect Pest Management in Rice Crop for a Bumper Harvest

This pest causes severe damage in nursery heds. Newly hatched larvae cut leaves and cause plants to look sickly with withered tips. Older larvae feed voraciously and cause almost complete defoliation. These larvae migrate from fields and do damage at night.
Control Measures
In case of moderate to severe damage, Drain the water from the nursery and spray chlorpyriphos 20 EC 80 ml during the late evening

6) Army Worm or  Earhead Cutting Caterpillar; (Mythimna separate )

Insect Pest Management in Rice Crop for a Bumper Harvest

The caterpillars are greenish-brown in color with a pair of prominent dorsolateral stripes on the body. Larvae feed voraciously on leaves, resulting in skeletonizing of leaf blades. They have a climbing habit and cut panicles from the base and do damage at night. The insect migrates from one field to another.
Control Measures
Spray any of the given insecticide like Quinalphos 25 EC @ 1,600 ml/ha or Chlorpyriphos 20 EC @ 2,000 ml/ha or Carbaryl 50 WP @ 1,500 g/ha or Phosalone 35 EC @ 1,100 ml/ha

7) Gundhi Bug; (Leptocorisa oratorio )

Insect Pest Management in Rice Crop for a Bumper Harvest

Both nymphs and adults cause damage by sucking the plant sap and particularly the milky juice of the developing grains in the early morning hours or at dusk. The grains are then either empty or partly filled and shriveled
This pest is popularly known as Gundhi bug because it produces a pleasant smell when touched or disturbed.
Control Measures
In this case, there are five or more insects per metre row length, as a control measure apply Carbaryl 50 WP @ 1,500 g/ha during afternoon hours. or Dust Malathion or Carbaryl @ 30 kg of the formulation/ha

8) Mole Cricket ( Gryllotalpidae )

Insect Pest Management in Rice Crop for a Bumper Harvest

This is a problem with raised nursery beds and in upland fields. Flooded rice becomes infested only when water is removed from the field. The adults of this pest feeds on the tender roots and lower portions of the plant below the ground. They may kill the plant by cutting at the base.
Control Measures

1) Maintain standing water
2) Encourage biological control agents: sphecid wasp, carabid beetle, nematodes, and fungus; mole crickets eat each other when they are together because of their cannibalistic behavior
3) It can be control by the poisinous insects by baits that are made by mixing moistened rice bran and insecticide and placing it along the entire bunds of the rice field or drier areas of the field
4) Apply Furadan 3 percent G at the rate of 33 kg per hectare or Thimet 10 percent G at the rate of 10 kg per hectare for the control of this pest.

9) Green Leaf Hopper ( Nephotettix virescens )

Insect Pest Management in Rice Crop for a Bumper Harvest

Generally, leafhoppers feed on leaves and upper parts of plants by sucking cell sap. It also transmits tungro virus disease. The disease is Characterised by slight stunting and reduced tillering. Young leaves are often mottled with pale-green to whitish stripes. Infected plants posses only few light spikelets.
Control Measures;
It can be control by the application of the insecticides like Imidacloprid 200 SL @ 125 ml/ha or Thiamethoxam 25 WG @ 100 g/ha or Ethofenprox 10 EC @ 500 ml/ha or Acephate 50 WP @ 950 g/ha or  Carbaryl 50 WP @ 900 g/ha

10) Brown Plant Hopper ; (Nilaparvata lugens)

1) These are of two types-white backed plant hopper and brown plant hopper (BPH)

2) White-backed plant hopper is common in the early crop season (July -August) whereas brown plant hopper appears during the later part of the crop season (October November). 3) Both the plant hoppers cause ever damage by sucking plant sap. This serious damage is called as the Hopper burn
4) A large number of plant hoppers are confined to the basal portion of the plant. Due to sucking plant sap by these pest there is yellowing of plants followed by rapid drying. 
5) Brown plant hopper in addition to cause direct damage also transmits “grassy stunt virus disease.” The disease is characterized by narrow, erect leaves which are usually yellow to yellowish-green with numerous dark spots. If the plant produces panicles they are small and have dark brown unfilled grain
Control Measures;
In case plant happens population reaches five to ten per bill, treat the stop with Spray of  Imidacloprid 200 SL @ 125 ml/ha or Thiamethoxam 25 WG @ 100 g/ha or Ethofenprox 10 EC @ 500 ml/ha or Acephate 50 WP @ 950 g/ha  Carbaryl 50 WP @ 900 g/h  Care should be taken to direct the sprays towards the base of the plants, particularly for the control of plant hoppers as they remain on husal part of the plants.

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