🌾 Rice Pests Part 1: The Six Major Enemies of Paddy

Walk into any paddy field in Tamil Nadu during the tillering stage and you may notice something alarming: circular patches of brown, dried-up plants that look as if someone set fire to them. This is "hopper burn" — caused by the Brown Plant Hopper (BPH) sucking sap from thousands of rice tillers. Rice is the staple food of over half of India's population, and it faces attack from more than 100 insect species, of which about 20 are economically important. In this lesson, we cover the six major pests that cause the most damage and appear most frequently in competitive exams.

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Rice Pests at a Glance

Rice Pests — Quick Reference Table

Pest	Scientific Name	Family	Order	Key Damage
Brown Plant Hopper (BPH)	Nilaparvata lugens	Delphacidae	Hemiptera	Hopper burn (circular patches)
Yellow Stem Borer	Scirpophaga incertulas	Pyralidae	Lepidoptera	Dead heart / white ear
Gall Midge	Orseolia oryzae	Cecidomyiidae	Diptera	Silver shoot (onion needle)
Green Leafhopper (GLH)	Nephotettix virescens	Cicadellidae	Hemiptera	Tungro virus vector
Thrips	Stenchaetothrips biformis	Thripidae	Thysanoptera	Silvery streaks on leaves
Rice Hispa	Dicladispa armigera	Chrysomelidae	Coleoptera	Transparent leaf blotches

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Understanding the Pest Categories

Before studying individual pests, note that rice pests fall into clear functional groups:

Category	Pests	Damage Type
Sap suckers	BPH, GLH, Thrips	Drain plant vitality; cause yellowing and drying
Stem borers	Yellow Stem Borer	Bore inside stem; cause dead heart and white ear
Gall makers	Gall Midge	Cause abnormal growth (silver shoots)
Leaf feeders	Rice Hispa	Mine leaves and scrape tissue

This grouping helps because exam questions often ask about damage types rather than specific pests.

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1. Brown Plant Hopper (BPH) — Nilaparvata lugens

Family: Delphacidae | Order: Hemiptera

Host range: Rice, sugarcane, grasses

BPH is arguably the most feared pest of irrigated rice in Asia. It caused the infamous "hopper burn" epidemics in the 1970s-80s that devastated rice production across Southeast Asia and India.

Damage Symptoms

• Nymphs and adults congregate at the base of the plant above the water level and suck sap from the tillers
• Affected plants dry up and give a scorched appearance called "hopper burn"
• Circular patches of drying and lodging of matured plants are the typical field symptom
• BPH is the vector of grassy stunt, ragged stunt, and wilted stunt diseases — the virus transmission makes it doubly dangerous

Management of BPH (also applies to WBPH and GLH)

• Spray Imidacloprid (a neonicotinoid)
• Avoid closer spacing — crowded canopy creates a humid microclimate that favours BPH
• Alternate wetting and drying of paddy fields — disrupts BPH habitat
• Adopt planting with alleys of 25 cm at intervals of 2 m to provide good aeration and sunlight
• Use light traps to monitor and mass-trap adults

Agricultural context: In the Cauvery delta of Tamil Nadu and the Godavari delta of Andhra Pradesh, BPH outbreaks are common during the samba and thaladi seasons. Extension workers advise farmers to check the base of plants (not the leaves) for BPH — because these hoppers hide at the stem base, they are often missed during casual field visits.

BPH was sporadic in 1958 and 1962 but has now become a key pest of irrigated rice. Wide spacing of transplanted seedlings reduces BPH buildup in endemic areas by improving aeration and reducing the humid microclimate that BPH prefers.

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2. Yellow Stem Borer — Scirpophaga incertulas

Family: Pyralidae | Order: Lepidoptera

Host range: Rice only — this is a monophagous pest (absolute pest), meaning it feeds exclusively on rice.

The yellow stem borer is the single most widespread and consistently damaging pest of rice across India. Every rice-growing state reports stem borer damage.

Damage Symptoms

• The caterpillar bores into the stem (hibernates in rice stubbles between seasons) and causes two distinct symptoms depending on the crop stage:
  • Vegetative stage: Drying of the central shoot known as "dead heart" — the central leaf turns brown and can be pulled out easily
  • Reproductive stage: Drying of the panicle called "white ear" — the ear emerges but is completely empty
• Damage ranges from 30-80% in severe infestations
• Only the caterpillar is destructive — it bores and feeds inside the stem (Asked in IBPS PSB-2019)
• Affected panicles are devoid of grains

Management

• Grow resistant varieties: Ratna, Jaya, TKM 6, IR 20, IR 26, Sayasree, Saket
• Clip the tips of seedlings before transplanting — this removes egg masses laid on leaf tips
• Release the egg parasitoid Trichogramma japonicum twice (on 30 and 37 DAT) @ 5 cc/ha/release
• Apply Bacillus thuringiensis var kurstaki + neem seed kernel extract (2.5 g/L + 1%) to reduce oviposition
• Set up light traps to attract and kill moths

Agricultural context: Farmers in Punjab and Haryana are advised to destroy rice stubbles after harvest (by incorporation or composting, not burning) because stem borer larvae hibernate in the stubbles and emerge the following season.

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3. Gall Midge — Orseolia oryzae

Family: Cecidomyiidae | Order: Diptera

Host range: Rice, wild Oryza species, and grasses like Paspalum scrobiculatum, Panicum spp., Cynodon dactylon, and Eleusine indica

The gall midge is a tiny fly whose maggot causes a very distinctive and unusual symptom in rice.

Damage Symptoms

• The maggot feeds at the base of the growing shoot, causing the formation of a tube-like gall that looks like an "onion needle" or "silver-shoot"
• The silver shoot is hollow, elongated, and silvery-white in colour
• Infested tillers produce no panicles — each silver shoot represents a lost tiller
• Particularly severe in upland and semi-deep water rice

Management

• Use resistant varieties: IR 20, IR 50, CR 1009
• Apply neem cake @ 12.5 kg/800 m2 nursery as basal dose

Agricultural context: Gall midge is particularly damaging in the rain-fed rice areas of Odisha, Jharkhand, and Chhattisgarh. The silver shoots are easy to spot in the field — they stand out like silver tubes among the green tillers.

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4. Green Leafhopper (GLH) — Nephotettix virescens

Also: N. nigropictus and N. cincticeps

Family: Cicadellidae | Order: Hemiptera

Host range: Rice, millets, grasses

GLH is important not so much for its direct feeding damage but primarily as a virus vector.

Damage Symptoms

• Both nymphs and adults suck sap from leaves, causing "hopper burn" in heavy infestations
• Yellowing of leaves from tip downwards is the typical direct damage symptom
• Far more important as a vector for rice tungro virus, rice yellow dwarf, and transitory yellowing diseases
• Tungro is the most destructive viral disease of rice, causing stunting, yellowing, and drastic yield loss

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5. Thrips — Stenchaetothrips biformis

Family: Thripidae | Order: Thysanoptera

Host range: Echinochloa sp. and rice

Thrips are tiny, slender insects that are most damaging in the nursery stage.

Damage Symptoms

• Both nymphs and adults lacerate the tender leaves and suck plant sap
• Cause yellow or silvery streaks on the leaves of young seedlings
• Terminal rolling and drying of leaves from tip to base is the typical symptom
• Cause damage both in nursery and main field, but nursery damage is most critical

Management

• Grow resistant cultivars: PTB 12, PTB 20, PT 321, H 4

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6. Rice Hispa — Dicladispa armigera

Family: Chrysomelidae | Order: Coleoptera

Rice hispa is unique among rice pests because the larva is a leaf miner while the adult scrapes leaf tissue — two completely different feeding modes in the same species.

Damage Symptoms

• Larvae (leaf miners) produce transparent blotches on the upper surface of the leaf
• Adults feed on green matter and produce whitish streaks parallel to the midrib
• The field develops a white, dried-up appearance
• Serious pest of rice, particularly in eastern India

Management

• Larval parasitoid: Eulophus femoralis
• Clip off leaf tips before transplanting seedlings
• Flood nursery beds with water
• Chlorpyriphos @ 625 ml

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Field Diagnosis Decision Tree

When you walk into a damaged paddy field, follow this flowchart to identify the pest:

Step 1: Where is the damage?

• Damage at stem base → Go to Step 2A
• Damage on leaves → Go to Step 2B
• Damage on panicle/ear → Likely Yellow Stem Borer (white ear — empty panicle, pull test positive)

Step 2A: Stem base damage

• Circular brown dried patches (hopper burn)? → BPH — check for tiny brown hoppers at stem base above water level. ETL: 8-10/hill
• Central shoot dries and pulls out easily (dead heart)? → Yellow Stem Borer — look for bore hole on stem with frass. ETL: 2 egg masses/m²
• Silver tubular hollow galls replacing tillers? → Gall Midge — break open the silver shoot, look for pink/orange maggot inside. ETL: 10% silver shoots

Step 2B: Leaf damage

• Silvery/yellow streaks + rolled leaf tips (nursery)? → Thrips — shake seedlings over white paper, tiny insects visible. ETL: 60/12 sweeps
• Yellowing from leaf tip downward + stunted plants? → GLH — tap plants, small green wedge-shaped hoppers jump. Check for tungro (orange-yellow stunting). ETL: 2-10/hill
• White streaks parallel to midrib OR transparent blotches? → Rice Hispa — look for spiny blue-black beetles on leaves. Blotches = larval mining, streaks = adult scraping

Pro tip for IBPS AFO aspirants: Always check stem base first (part the canopy and look at water level) — BPH and stem borer cause the most economic damage but are easily missed because they hide inside or at the base of the plant.

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Comparing the Big Six — Damage Pattern Table

Pest	Symptom Name	What to Look For in the Field	Plant Part Affected
BPH	Hopper burn	Circular brown patches; insects at stem base	Stem base
Stem Borer	Dead heart / White ear	Central shoot pulled out easily; empty panicles	Stem
Gall Midge	Silver shoot	Silver tubular galls replacing tillers	Growing point
GLH	Yellowing / Tungro	Leaf tips yellowing; stunted orange-yellow plants	Leaves (+ virus)
Thrips	Silvery streaks	Rolled, dried leaf tips in nursery	Young leaves
Hispa	Transparent blotches	White streaks and mined patches on leaves	Leaves

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Exam Tips and Mnemonics

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ETL Summary Table

Pest	ETL
BPH (Nilaparvata lugens)	8-10 Nos./hill (20 Nos./hill if spider present)
Yellow Stem Borer (Scirpophaga incertulas)	2 egg masses/m2
Gall Midge (Orseolia oryzae)	10% silver shoots
GLH (Nephotettix virescens) — Nursery	60 Nos./25 sweeps
GLH — Vegetative stage	5 Nos./hill
GLH — Flowering stage	10 Nos./hill
GLH — Tungro endemic area	2 Nos./hill
Thrips (Stenchaetothrips biformis)	60 Nos./12 wet hand sweeps (nursery)

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Summary Cheat Sheet

Concept / Topic	Key Details
BPH (Nilaparvata lugens)	Delphacidae, Hemiptera; sucks sap at stem base above water
BPH symptom	Hopper burn — circular brown patches of dried plants
BPH ETL	8-10 insects/hill (20/hill if spider present)
BPH transmits	Grassy stunt, ragged stunt, wilted stunt viruses
BPH management	Imidacloprid; alternate wetting-drying; avoid close spacing
Yellow Stem Borer (S. incertulas)	Pyralidae, Lepidoptera; monophagous (rice only) = absolute pest
Stem borer symptoms	Dead heart (vegetative) + White ear (reproductive)
Stem borer ETL	2 egg masses/m²
Stem borer damage	30-80% in severe infestations
Stem borer biocontrol	Trichogramma japonicum (egg parasitoid); clip seedling tips
Resistant varieties (stem borer)	Ratna, Jaya, TKM 6, IR 20, IR 26
Gall Midge (Orseolia oryzae)	Cecidomyiidae, Diptera; maggot causes tube-like gall
Gall midge symptom	Silver shoot / Onion needle — hollow, silvery-white tube
Gall midge ETL	10% silver shoots
GLH (Nephotettix virescens)	Cicadellidae, Hemiptera; vector of rice tungro virus
GLH ETL	Nursery: 60/25 sweeps; vegetative: 5/hill; tungro area: 2/hill
Thrips (S. biformis)	Thripidae, Thysanoptera; silvery streaks; leaf rolling from tip
Thrips ETL	60/12 wet hand sweeps (nursery) — most important nursery pest
Rice Hispa (Dicladispa armigera)	Chrysomelidae, Coleoptera; larva = leaf miner, adult = scraper
Hispa symptoms	Larva: transparent blotches; Adult: white streaks parallel to midrib
Hispa parasitoid	Eulophus femoralis