INSECT PESTS OF RICE

R. RegmiAssistant professor

Department of entomology

INSECT PEST OF RICE

• Rice (Oryza sativa L.) is the most important staple food crop of the world

• More than 60 % of worlds population depend on it for food.

• It is major crop of Nepal accounting 55% of total national cereal production.

• It is cultivated in 1,420,570 ha with production of 4,504,503 mt ton.

• Insect pests are responsible for average 25-30% loss in Nepal

Major insect pests

Brown Plant Hopper, Nilaparvata lugens (Homoptera: Delphacidae)

Yellow Rice Stem Borer, Scirpophaga incertulas (Lepidoptera: Pyralidae)

Rice Ear-head Bug, Leptocorisa oratorius (Hemiptera: Alydidae)

Rice Hispa, Dicladispa armigera (Coleoptera: Chrysomelidae)

Rice Grasshopper, Hieroglyphus banian (Orthoptera: Acrididae)

Minor insect pests Rice Mealybug, Brevennia rehi (Homoptera: Pseudococcidae)

Pink borer, Sesamia inferens (Lepidoptera: Noctuidae)

Rice Gall Midge, Orseolia oryzae (Diptera: Cecidomyiidae)

Whorl Maggot, Atherigonna oryzae (Diptera: Muscidae)

Mole Cricket, Gryllotalpa africana, (Orthoptera: Gryllotalpidae)

Seed Bed Beetle, Heteronychus lioderes (Coleoptera: Scarabaeidae)

Rice pollen Beetle, Chiloloba acuta (Coleoptera: Cetonidae)

Rice Brown semi-looper, Mocis frugalis (Lepidoptera: Nocutidae)

Rice semilooper, Chrysodeixis chalcites (Lepidoptera: Nocutidae)

Continue minor insects pest Yellow caterpillar, Psalis pennatula (Lepidoptera: Lymantridae)

Black hairy caterpillar, Amata sp. (Lepidoptera: Amatidae)

Rice Grasshopper, Hieroglyphus nigrorepletus/ Catantops pinguis/Attractomorpha burri/A. crenulata/Oxya adenttata/O. ebneri (Orthoptera: Acrididae)

Rice Field Cricket, Gryllus bimaculatus/ Teleogryllus occipitalis (Orthoptera: Gryllidae)

Rice Thrips, Stenochaetothrips biformis / Perrisothrips sp./ Haplothrips sp./ Chloethrips oryzae(Thysanoptera: Thripidae)

Stripped Rice Borer, Chilo partellus/ C. Polychrusus/ C. suppressalis (Lepidoptera: Pyralidae)

Rice aphid, Rhopalosiphum rufiabdominalis/Macrosiphum avenae (Homoptera: Aphididae)

Minor pests of rice

1. Pollen beetle 2. Rice semilopper 3.Green horned catterpilllar

4. Rice green leaf hopper 5. Mole cricket 6. Rice skipper

7. Rice mealy bug 8. Whorl Maggot 9. Pink borer

10. Rice Swarming caterpillar 11. Rice ear cutting caterpillar 12. Rice thrips

SCIRPOPHAGA INNOTATA (WHITE RICE STEM BORER)

Rice leaf folder, Cnaphlocrosis medinalis

Leaf feeding or leaf damaging insects Rice Ear- Cutting Caterpillar, Mythimna separata (Lepidoptera,

Noctuidae) Rice Swarming caterpillar, Spodoptera Mauritia (Lepidoptera,

Noctuidae) Rice caseworm, Nymphula depunctalis (Lepidoptera: Pyralidae) Rice leaf floder, Cnaphalocrocis medinalis (Lepidoptera: Pyralidae) Rice green horend caterpillar, Melanitis leda ismene (Lepidoptera:

Satyridae) Rice skipper, Pelopidas mathias (Lepidoptera: Hesperiidae) Rice Hispa, Dicladispa armigera (Coleoptera: Chrysomelidae) Rice Grasshopper, Hieroglyphus nigrorepletus/ Catantops

pinguis/Attractomorpha burri/A. crenulata/Oxya adenttata/O. ebneri (Orthoptera: Acrididae)

Rice Field Cricket, Gryllus bimaculatus/ Teleogryllus occipitalis (Orthoptera: Gryllidae)

Sap sucker from leaf and leaf sheath Rice leafhoppers, Nephotettix nigropictus (Homoptera: Cicadellidae)

Green rice leafhoppers, N. Virescens (Homoptera: Cicadellidae)

Zig Zag leaf hopper, Recilia dorsalis (Homoptera: Cicadellidae)

White rice leaf hopper (Homoptera: Cicadellidae)

Brown plant hopper, Nilaparvata lugens (Homoptera: Delphacidae)

White back plant hopper, Sogatella furcifera (Homoptera: Delphacidae)

Rice Mealybug, Brevennia rehi (Homoptera: Pseudococcidae)

Rice aphid, Rhopalosiphum rufiabdominalis/Macrosiphum avenae (Homoptera: Aphididae)

Rice Thrips, Stenochaetothrips biformis / Perrisothrips sp./ Haplothrips sp./ Chloethrips oryzae(Thysanoptera: Thripidae)

Stem and heart damaging insects Yellow Rice Stem Borer, Scirpophaga incertulas

(Lepidoptera: Pyralidae)

White Rice Stem Borer, S. innotata (Lepidoptera: Pyralidae)

Pink borer, Sesamia inferens (Lepidoptera: Noctuidae)

Rice Gall Midge, Orseolia oryzae (Diptera: Cecidomyiidae)

Whorl Maggot, Atherigonna oryzae (Diptera: Muscidae)

Stripped Rice Borer, Chilo partellus/ C. Polychrusus/ C. suppressalis (Lepidoptera: Pyralidae)

Root damaging insects

Mole Cricket, Gryllotalpa africana, (Orthoptera: Gryllotalpidae)

Seed Bed Beetle, Heteronychus lioderes (Coleoptera: Scarabaeidae)

Flower and grain damaging insects

Rice Ear-head Bug, Leptocorisa oratorius (Hemiptera: Alydidae)

Rice pollen Beetle, Chiloloba acuta (Coleoptera: Cetonidae)

1. Brown Plant hopper, Nilaparavata lugens (Homoptera: Delphacidae)

• It is most destructive pest.• Both nymph and adult feed on paddy,

sugarcane and grasses by sucking cell sap.• The brownish adults with brown eyes are

3.5 – 4.5 mm in length.• Their legs are light brown and the tarsal

claw are black.• The wings are hyaline with brown marking

and dark vein.• The nymphs are brownish black in colour

and have grayish blue eyes.

Life cycle of BPH• The adult remain most active from 10 to 32 degree C.• The females start laying eggs within 3-10 days of their emergence

& deposit eggs in masses, by lacerating the parenchymal tissue. • The number of eggs per mass varies from 2 to 11 and female lays

on an average 124 egg masses.• The eggs are somewhat dark and cylindrical having two distinct

spots.• The incubation period ranges between 4 to 8 days.• The nymphs on emergence start feeding on young leaves and

after moulting 5 times, they become adults in 2-3 weeks.• The life cycle is completed in 18-24 days during June-October,

38-44 days during November – January and 18-35 days during February -April.

Damage• Both nymph and adults cause damage by sucking cell sap from

the leaves which turn yellow.

• A heavy infestation produce symptoms of “ hopper burn” i.e. leaves become dry and brown after insect feeding and patches of burned plants are often lodged.

• It has been noticed that even at low infestation the tillering is adversely affected and there diminished vigor and decreases in plant height.

• Under the favorable condition of high humidity, optimum temperature, high nitrogen application and no wind the population increases very rapidly.

• The insect is known to transmit the grassy stunt virus disease of rice.

NILAPARVATA LUGENS (BROWN PLANTHOPPER)

Management

• Avoid closer spacing of planting

• Alternate drying and wetting the fields during peak infestation and draining out the standing water from the field 2-3 times.

• Alleys 30 cm wide after every 3 meters of rice planting provide proper aeration to the crop which ultimately restricts the multiplication of the pest.

• Grow resistant varieties IR26, IR36, IR56, IR56, IR64, & IR72

• Spray at economic threshold 5-10 insects per hill, 100 ml imidachloroprid or 625 g of Carbaryl 50WP or 2.0 lit of Quinalphos 25EC in 250 liter of water and repeat if hopper population is persist

2. Yellow Rice Stem Borer, Scirpophaga incertulas (Lepidoptera: Pyralidae)

• The yellow stem borer is a specific pest of rice.

• The caterpillar alone are destructive, when full grown, they measure about 20mm and are dirty white or greenish yellow having brown head and pronotum.

• The adult have a wing span of 25- 45 mm and are yellowish white with orange yellow front wings.

• The female moth is bigger than the male and has a centrally situated black spot on each of the forewing.

• The female have prominent tuft of brownish yellow silken hair at the tip of their abdomen.

Life cycle of YSB The moth becomes active after dusk when they mate and lay

about 120- 150 eggs on underside of the leaves in 2-5 cluster of 60-100 eggs each.

The eggs are covered with yellowish brown hair of the female tuft.

The eggs are oval flattened pearly white at the times these are laid, but turns black before hatching.

They hatch in 6-7 days and the tiny black headed caterpillar soon bore into the stem from the growing point downward.

When a tiller is killed, the caterpillar inside migrates to another tiller of the same or of different plant.

The larva grows in 6 stages and is full fed in 16-27 days. It then constructs an emergence hole which is always located

above the water level and pupates inside the attacked plant. Within 9-12 days it emerge as a moth. The life cycle is completed in 31-46 days.

Damage of YSB

• The larval feeding damage may cause death of the central leaf whorl at the vegetative stage, which is known as dead heart.

• Damage at the reproductive stage causes ear devoid of grain, which is known as white head.

SCIRPOPHAGA INCERTULAS (YELLOW RICE STEM BORER)

Management of YSB:

• The removal and destruction of stubble at the time of the first ploughing after harvesting the crop.

• Ploughing and flooding the field is also effective in killing the larvae

• Clipping of tips of seedling before transplanting can reduce the carryover of eggs to the field.

• Use trichocard with 50,000-1,00,000 Trichogramma per ha after 3-4 weeks

• The field showing more than 5% dead hearts should be sprayed 25kg of Cartap hydrochloride 4G or 15 kg of Fipronil 0.3 G per ha in standing water in the field.

3. Rice ear- head bug, Leptocorisa oratorius/ L. acuta (Hemiptera: Alydidae)

• The adult of Leptocorisa oratorius is green, light brown or mixed yellow in color.

• The adult are slender and about 20mm long.• Males and female are 13-14mm and 16-19mm long

respectively. • The head is triangular. • The antennae consist of four segments. • They have long legs.• The abdomen of both male and female is constricted slightly

in the middle. • The abdomen of females is somehow inflated(magnified).• There are stink gland on either side of the abdomen that

emit foul odour, hence called stink bug or Gandhi bug. • The grown up nymph are very similar to the adult in color

and size, but they are wingless.

Life cycle of REHB: • The rice earhead bug breeds all the year round

• Generally most active from August to November.

• The female lay 250-300 eggs at night in 2-3 straight row consisting of 20-30 round yellow eggs along the midrib on the upper surface of the leaf blade.

• The eggs are 2 mm long disc shaped or dorsally flat and elliptical, with a slightly granulated and shiny surface.

• The egg hatch within 6-7 days and the nymph grow to maturity over six instars within 2-3 weeks.

• The first instar nymph is very small 2 mm long and pale green which turns into deep green during the following instar.

• The adult bug live for 33-35 days.

• Breeding also take place during winter though at slower rate.

Damage of REHB

• The pest is essentially diurnal with highest activities in the morning and in the evening, seeking shelter during hoter parts of day.

• Many generation are completed in a year.

• Adult and nymph both suck the sap of developing rice grains at the milking stage and cause considerable yield loss.

• Sucking of the grain sap causes empty or partially filled and chaffy grains and enhances subsequent fungal and bacterial infection.

Management:• The population can be suppressed by killing the bug by using light

traps.

• Collection of adult bug using net

• Destroy weed to remove alternate host

• Keep on hanging the cattle urine soaked gunny bags or cow dung wrapped cloth in the field to attract the bug.

• Synchronize rice planting to maintain simultaneous crop maturity in the field in an area for equal distribution of bugs in all fields

• Conserve predator of rice bug like tiger beetle, Cicindela sexpunctata by using chemical pesticide judiciously.

• Spray after at least 10 bug per 100 panicles with pesticide like carbaryl (Carbaryl 5% dust@25kg/ha)

• Spray Fenvalerate 20 EC 0.5ml/liter of water

4. Rice Hispa, Dicladispa armigera (Coleoptera: Chrysomelidae)

• The adult is a small bluish black beetle

• Measuring 5mm in length and is recognized by numerous short spines on the body, which give it a characteristics appearance.

• The legless creamy white larvae are not easily seen because they are concealed inside the leaves tissue.

Life cycle RH• This pest breeds actively from May to October and hibernates

during winter probably in the adult stage.

• In May, the beetle starts laying eggs on nursery plants.

• The eggs are embedded in the leaf tissue towards the tip.

• On hatching the young grubs feed as leaf miner, between the upper and lower epidermis.

• The attacked leaves turn membranous showing characteristics blisters or blotches.

• Later on, the attacked leaves wither and die.

• When the larva are full grown, they pupate inside and finally emerge as black beetle.

Damage:

Larvae cause damaged like leafminer.

The adults also feed on green matter and produce parallel whitish streaks on the leaves.

The damage starts in nurseries and spread to the rice fields.

Management:

• Clipping the infested leaf tip during transplanting • Nursery bed is flooded and damaged beetles

flooded in water.• Spray start at economic threshold level(1 adult

per hill). • Spay 2-5 liter Chlorpyriphos 20EC or 2. 0 lit of

Quinalphos 25 EC in 250 liter of water per ha and repeat spray after 2 weeks if attack continue.

5. Rice Grass hopper, Hieroglyphus banian/ H. nigrorepletus(Orthoptera: Acrididae)

• Various species of grasshopper are widely distributed in Nepal.

• They are polyphagous and feed on leaves of rice, maize, millets, sugarcane, grasses etc.

• The adult are 40-50 mm long and are shining greenish yellow, having 3 black lines running across the pronotum.

• Nymph are yellowish with many reddish brown spot in the early stages but become greenish as they grow older.

Life cycle GH• Hieroglyphus spp.have one generation in a year and pass the

winter & dry part of summer in egg stage. • The eggs are found in the soil and they hatch in June or in early

July, a few days after the first shower of the monsoon.• On emergence, the nymphs start feeding actively and complete

their development in seven stages within 3 weeks. • The adult are seen feeding voraciously during August and

September. • When they are 2 month old, they mate. • The female starts laying eggs by inserting her abdomen in the

soil.• The egg are laid 5-8 cm deep in pod, each containing 30-40 eggs.

Damage GH

• Both adult and Nymph cause damage causing defoliating.

Management:

• Fish cum Rice farming • Larva of the banded blister beetle (Mylabris

phalerata) attack the eggs of the rice grasshopper.

• Trimming the bund and field sanitation reduces the grasshopper population.

• Spray chlorpyriphos 2.5 lit Chlorpyriphos 20EC in 250 liter of water per ha.

Thank you