GUNDHI BUG OF PADDY

GUNDHI BUG OF PADDY

(   Leptocorisa oratorius )

Order:  Hemiptera

Family: Alydidae

1. Name of Pest: Gundhi Bug or Rice bug or stink bugs or Ear head bug.

2. Host plants: Paddy  

3.When its occur:

• The maximum population is usually observed during September to November months.
• Favorable Temperature 27° 28°C Relative Humidity 80-82%.
• The population of the rice bug increases at the end of the rainy season.
• They are less active during the dry season.
• Adults are active during the late afternoon and early morning. Under bright sunlight, they hide in grassy areas.
• They are more common in rainfed and upland rice and prefer the flowering to milky stages of the rice crop.
• The bugs prefer to attack milk stage grains.

4. How to identify insect pest:

• Eggs: oval, shiny, and reddish brown eggs.Female lay 250-300 eggs in two or three straight rows alongside mid rib on upper surface of leaf blade.

• Nymphs: Newly hatched nymphs are green but turn brown as they grow.2 mm long,Nymphs feed gregariously.

• Adult : Adults are greenish yellow.long and slender and measures about 16-19 mm long .Diurnal(Daytime) in habit but active during early morning and evening.feeding on endosperm of rice grains.

🔺 Rice fields severely affected by the bug emit a repugnant smell, hence the name gundhi bug.

5. What does it do :

Damage Symptoms of Gundhi bug in Paddy

Both adults and nymphs damage rice by sucking out the contents of developing grains from Pre-flowering spikelets to soft dough stage, therefore causing whitish spots appear at the site of feeding. Black or brown spots appear around the holes made by the bugs on which sooty mould may develop. Unfilled or empty grains and discoloration. The infested grains easily break during milling. Immature and adult rice bugs both feed on rice grains.

6. Damage Symptoms:

• The nymphs and adults suck the milk from the developing grains and stem in the early stage of grain formation.

• Due to de-sapping, grains show brownish discolored patches on the husk.

• Black spots on the grains at the site of feeding puncture.

• Discoloration of panicles as well as the presence of some empty or ill filled grains in the panicles.

• In the case of heavy infestation, the whole ear head may become devoid of mature grains.

• Infested paddy straw contains foul smell during milky stage.

7.Management Practice:

     A. Cultural Methods:

• Careful observation during milking stage.
• The removal of alternate hosts such as weeds and grasses in and out of paddy fields to prevent population build-up of rice bugs.

keep the field weed free 

• Cultural control measures include early planting, and the use of late-maturing variety.(Anamika, Dharitri,CR Dhan 304,CR Dhan 407, CR Dhan 507 etc (130-150 days).

Avoid of chemical spray

• Avoid the use of chemical pesticides so that the field is a suitable environment for natural predators of rice bugs, such as tiger beetles.

     B. Biological Methods:

• Small wasps Parasitize the eggs and the Meadow grasshoppers prey on (Kill) them.

                                                        

• Both the adults and nymphs are prey to   spiders,  Coccinellid beetles,   dragonflies.

     C. Mechanical and Physical Methods:(Trap Methods):

• Collection of the bugs by hand netting is suggested. Sweeping of rice plants with winnows smeared with sticky material like castor oil.

• Trap adult bugs using a light trap @ 1-2 no/acre, sweep net and dirty trap of cattle urine/dung and then destroy the traps by suitable means.
  

• Keep on hanging the cattle urine soaked gunny bag or cow dung wrapped cloth in the field, just at the height of the crop to attract the bugs.

• Use of 100 gms of oyster, snail or earthworm meat mixed with 8-10 drops of Chlorpyriphos 20% EC OR Fipronil 5 % SC @ 1 ml can be tied in a cloth bundle and the level of the sheaf in the paddy field can be tied in a stick. ( use 20 No cloth bundle per acre.)

     D. Chemical Methods: 

      👉 bug population observed during flowering stage, application of the insecticide may be done either before 9 a.m. or after 3 p.m. so that fertilization of the flowers is not adversely affected.

• 🚫 Spraying of Monocrotophos 1.6 ml or Endosulfan 2 ml per litre of water once at flowering and another at grain hardening stage or dusting of Endosulfan 4 % or Carbaryl 5 % @ 25 kg/ha in evening hours. If needed application has to be repeated after 10 days. 

• 🚫 Dusting of Malathion @ 30 kg/ha or spraying malathion 50% EC @ 2 ml/l of water or

• Spray Chlorpyriphos 20% EC @ 3 Ml/lit Of Water.

• Spray Imidacloprid 6 % +Lambda Cyhalothrin 4 % S.L @ 0.6 ml/ Liter of water or 300 ml/ha (500 Lit. of water)(INOVEXIA).

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