1. Identification of major insect pests of
Paddy and their damage symptoms
Dr. M. Thippaiah
professor
Dept. of Entomology
College of Agriculture
GKVK, UAS
Bangalore- 65
2. Rice, Oryza sativa is the most important and staple food crop for
more than two third of the population of India and more than 65 %
of the world population.
More than 100 Insect species are associated with rice crop at one
stage or the other stage
20 of these are pests of major economic significance and these
pests are classified as
Borer pests
Sucking pests
Defoliator pests
Non Insect pests
3. Insect PESTS OF PADDY
Yellow stem borer
Brown Plant hopper(BPH)
Earhead bug
Gall midge or Gall fly
Thrips
Green leaf hoppers (GLH)
Mealybugs
Borer pests of paddy
Scirpophaga incertulas
Orseolia oryzae
Sucking pests of paddy
1. Nephotettix nigropictus
2. N. virescens
White leaf hopper(WLH)
Cofana spectra
Nilaparvatha lugens
Leptocorisa oratoria
Stenchaetothrips biformis
Brevennia rehi
6. Panicle rice mite: Steneotarsonemus spinki
Non insect pests on paddy crop
Paddy mite : Oligonychus oryzae
Rice field crab : Paratelphusa hydrodromus
Field rat : Bandicota bengalensis
7.
8. Paddy stem borer : Scirpophaga incertulas (Walker)
(Pyralidae : Lepidoptera)
The adults are yellowish white with orange yellow front wings and they
have sexual dimorphism
The female moth is bigger than the male and has a centrally situated
black spot on each of the fore wings
The females also have a prominent tuft of brownish silken hair at the tip
of their abdomen
Moths are attracted to light in the night during March-April and
October-November
9. Male moths are small with Female moths are bigger
pale yellow fore wings and fore wings are bright yellow
without black spot in the and a prominent black spot
centre and abdomen slender in the centre of each and the
with out tuft of hairs anal end with tuft of yellowish hairs
10. Eggs are creamy coloured
, flat, oval, laid in masses
and covered with buff
coloured hairs on the tip
of the leaf
The body of the larva is cream or
Pale white or yellow colored and
the head is reddish brown
Pupa turns dark brown just
before adult emergence Adult moth
Pupate at the base
of the plant
12. Young larva, bore into
the central shoots of
young seedlings and
tillers, and feeds internally
on growing shoot causing
‘dead hearts’ symptom i.e
drying of the central shoots
and interrupting movement
water and nutrients
At boot leaf stage or ear
head stage – the larva
bores in to the top most
node and feed at the
base of the ear head and
succulent ear head dries
and becomes white ear or
chaffy ear head and such ear
heads are easily come out
when they are pulled out
Nature and symptoms
of damage
14. Symptoms
The pest can be identified with the following symptoms
Dead heart at vegetative stage which turns brownish, curls and dries
White ears at ear heading stage with empty, partially filled grains
Presence of egg masses near the tips of tender leaf blades
Activity of moths in the vicinity
Frass at the feeding site
15. Reasons for attaining major pest status
Expansion of rice area to new irrigation system
Multiple rice cropping system
High yielding varieties
Application of higher dose of nitrogen
Optimum temp.- 17- 300 C for all the stage
If more than 350 C are not congenial
Warm humid condition i.e RH 80-90% are
more suitable for population growth
16. Paddy case worm : Nymphula depunctalis
(Pryalidae : Lepidoptera)
Adult is a tiny delicate moth measuring
about 1.5cm in length
Wings are white and speckled with pale
brown markings
pale brown
markings
17. Eggs are laid singly
or arranged in rows
at the tip of leaves
I.P- 5-6 days
• The caterpillar under
goes 6 instars and is
characterized by the
presence of tubular
gills on the body
• The larval length 11-12mm
and case length of 20-25mm
L.P – 18-22 days
Pupation takes place inside
last larval case after attaching
the leaf sheath above the
water level and closing two ends
PP – 5-6 days
Adult is a tiny delicate
moth measuring about
1.5cm in length
Wings are white and
speckled with pale
brown markings
Life cycle
TLC – 30-40 days
18. The pest attacks the crop in the early transplanted stage
The young larva cut the leaf blade into small bits and constructs
a tubular case and larva remains inside the case
The larva feeds on foliage by scraping the green matter
As a result White patches are seen on the leaf blades in ladder like
fashion on the under surface of the leaves
Tillers become stunted and loose their vigour and often
the plants are killed
19. 1. Leaf cases floating on water
2. Leaves cut at right angles to
make cases
3. Leaves with papery upper
epidermis that were fed on
by larva
4. Skeletonized leaf tissues usually
appear ladder-like fashion or
ladder like scrapings
5. The tillers become stunted
6. Loss of vigour in plants
7. Maturity delayed by 7-10 days
Symptoms
21. Paddy leaf roller : Cnaphalocrocis medinalis
(Pryalidae : Lepidoptera)
Adult moth is a small and measures about 2 cm in length
Wings brownish yellow in colour with wavy distinct 2 or 3
dark markings
Male moths have a tufts of thick black hairs on the mid costa
22. These are small brownish yellow
coloured moths and they have two or
three distinct dark wavy lines on the
brownish fore and hind wings which
have a dark brown to gray band on
their outer margin.
Eggs are laid singly or
in pairs on the lower
surfaces of tender
leaf blade; Incubation
period is 4 – 8 days
Larvae are yellowish green
in colour with dark brown
head They fold leaf margin
longitudinally and feed the
rolled leaves; larval period is
15-27 days;
Pupation takes place
inside the leaf roll
PP - 6-8 days
Total life cycle is
26-42 days.
There are 4 generarions
/ year
Adult
Eggs
23. Larva yellowish green in colour and measures
about 16-20mm in length
Leaf folded
longitudinally
and larva live
inside
24. Nature of folds depends on the stage of the crop
The crop is at nursery stage i.e seedlings and young plants are attacked and 3-4
leaves of adjacent plants are webbed together forming longitudinal folds and feed on
green matter
In case of growing plants, one leaf folded longitudinally or transversely and larva
live inside by scraping green matter and infested leaves appear white and leaf
fold filled with excreta
Each larva damage the several leaves which prevents the photosynthetic activity of the plant
Nature and symptoms of damage
The pest damage throughout crop growing stage until boot leaf stage
25. Paddy leaf hoppers : a) Nephotettix virescens
1. Green leaf hoppers(GLH) b) Nephotettix nigropictus ( Cicadellidae : Hemiptera)
Adults are smaller in size, green coloured
insects with prominent black spot on the
apical portion of fore wing and two black
spots in the middle of the forewing and
do not extend up to the black distal portion
Adults are dark green in colour, with
prominent black spot on the apical
portion of fore wing and has two black
spots in the middle of the forewing and
extending up to the black distal portion
on the forewing
Nephotettix virescens Nephotettix nigropictus
Paddy leaf hoppers are found in all the rice growing regions of India
Adults are small green wedge shaped hoppers with hind legs having
one or two rows of spines
26. GLH is common in irrigated wet land environments
They are not prevalent in upland rice
Life stages of the pest
Eggs are insert into the midribs in groups of 3-18
I.P – 3-5 days
Nymphal stage is completed in 12-21 days
Adults live for 7-12 days
There are six overlapping generations/ year
27. White leaf hopper : Cofana spectra
(Cicadellidae : Hemiptera)
Adult are whitish in colour and bigger in size
This insect causes yellowing of leaves and stunting of tillers
It does not transmit any diseases and direct damage as hopper
burn rare
Stage of the crop pest attack – second half of crop growth period
and abundant only during the summer months
28. Nature and symptoms of Damage
The nymphs and adults cause direct damage to rice
crop by sucking sap from leaf sheaths and Leaf blades
and plants turns yellowish brown
The white specks on the young leaf are the symptoms
of damage, severe infestation leads to ‘hopper burn’.
The affected leaves and plants turn to yellowish brown
colour and growth is retarded.
They indirectly acts as vectors by transmitting
viral diseases such as RiceTungro virus ( RTV)
Transitory virus and
Yellow dwarf.
They also feed on some grasses
like Cynodon dactylon,
Echinochloa crusgalli and
Eleusine indica, etc.,
31. Brown plant hopper: Nilaparvata lugens
(Delphicidae : Hemiptera)
This is a number one enemy in Command areas , under favourable condition we can
except 100 % crop loss Adults are brown in
colour; 4-5 mm long,
yellowish brown to
dark brown body and
more or less wedge shaped
Hind tibia with a long
movable spur
Macropterans are strong fliers;
Eggs are elongated,
cigar shaped inserted
by female in two rows
on either side of the
midrib of the leaf sheath
I.P - 7-9 days
Young nymphs
are whitish in
colour and
measures 0.7
mm in length
N.P – 15-20 days TLC – 18-24 days
Eggs
32. Have well developed wings Have poorly developed wings
Smaller abdomen Larger abdomen
Move from one field to another Can not fly, move by irrigation water
field as colonies
Dominant at post flowering stage Dominant at pre flowering stage
Egg laying capacity is less Egg laying capacity is more
Macropterous form – Fully winged form Brachypterous form – Short winged form
Adult insects appears in two forms
33. Young nymphs are whitish in colour and measures about 0.7mm
in length and second instar nymphs are brownish black in colour
and they congregate at the base of the plant and later instar are
yellowish brown in colour
N.P- 15-20 days
34. Nature and symptoms of damage
• Stage of attack:- Early growth
stage but some times serious
infestation occurs at post
flowering stage
• Damaging stages:- Adults
(especially brachypterans) and
nymphs
Both nymphs and adults suck the sap from leaf sheath and stem at lower portion
of the plant, just above the water level, continuous drying of the plants due to
feeding. The crop turn yellow followed by rapid drying of plants called as hopper
burn in concentric rings and later spread to entire plot in severe case
• Nature of damage:-
Nymphs and adults Congregate
at the base of the plant causing
hopper burn
• Peak occurrence is between
Oct - Nov and Jan – Feb and the
pest more severe in summer crop due
to ideal condition, the loss is heavy
in high rainfall condition
35. Circular dry patches in field Completely desapped plant
Hopper burn more common in panicle initation stage to
maturity stage of the crop
36. They are also transmit viral diseases called grassy stunt virus i.e
It acts as vectors of viral disease
37. Most favourable conditions for pest out break
or
Reasons for BPH out break
Temp- 290C
RH-80-90%
Continuous cultivation of susceptible varieties
Continuous cultivation of monocrop
Use of high dose of nitrogenous fertilizers specially urea
Closer planting
Indiscriminate use of pesticides
38. Paddy thrips : Stenchaetothrips biformis
(Thripidae : Thysanoptera)
Nymph Adult
Adults are small, 1mm long or elongate dark brown to black
coloured insects, with narrow fringed wings
This pest is observed when there is a dry spell, low humidity and high temp. favours the
Pest build up
Eggs – are laid in
leaf tissues
Fecundity – 100eggs
I.P – 3-5 days
Nymphs – there are
5 nymphal instars
N.P – 10-12 days
TLC- 20-25 days
39. Initial - inward rolling
Symptoms of damage
Both nymphs and adults Lacerate the tender leaves and suck the plant sap
of the seedlings in nursery and young transplanted plants in the main field
Rolling and drying of the leaf tips i.e leaves curl longitudinally margin in wards
and all the stages with in leaf roll it self
Yellow (or) silvery streaks on the leaves of young seedlings
It causes damage both in nursery and main field
Silvery streak
40. Paddy gall midge: Orseolia oryzae
(Cecidomyiidae : Diptera)
Adult is a small, reddish, delicate fly, with long legs, resembling
a mosquito and moniliform antennae
Wings are semitransferens
The male is ash grey in colour
Adults feeds on dew drops
41. Eggs : are laid singly or in small clusters at the base of the leaves near ligules
and up to 200 eggs laid by each female
I.P – 3-5 days
Maggots: are minute, greyish white in colour, stout body and pointed towards
anterior end, fully fed maggot 3mm length, pinkish in colour
L.P - 7-15 days
Pupa : it pupate within the gall P.P – 3-8 days
Adults are positively phototrophic and lives for 1 to 5 days
The tillering stage of the paddy crop is more susceptible to attack of this pest
egg Larva
42. Nature and symptoms of damage
The maggots crawls down between leaf sheath and reaches the
growing point and start feeding and an oval shaped chamber is
formed around the site of feeding and the irritation caused due
to its feeing on primordia cover leads to formation of elongate
cylindrical gall called ‘silver shoot’ or Anekombu or kane or
Onion shoot
As a result, further growth of tiller is arrested / stop
The feeding by maggot and their larval secretion which contains
active substance called “Cecidogen” is responsible for cell
proliferation of the meristematic cells as a result
gall formation takes place
The galls are formed by gall fly are nothing but modification
of leaf sheath
The central shoot instead of producing leaf and produces a long
tubular structure called gall and when gall elongates as
an external symptoms of damage
Infested tillers not producing panicles
43. symptoms of damage
Damaged tillers turns into tubular galls
which dry off without bearing panicles
Main external symptom is SILVER SHOOT
or GALL which resembles onion leaf
Fully developed gall is a silvery white hallow tube
1 cm wide and 10 – 30 cm long
Attack to rice seedlings leads to profuse
tillering and these new tillers often
become infested
44. Reasons for out breaks of the pest
Early monsoon showers following a dry spell
Continuous cloudy weather associated with intermittent rains
High relative humidity
Optimum temperature ranges from 28 – 320 C
Late planting
High yielding susceptible varieties
Continuous cropping High nitrogen application
Closer plant spacing
Intensive management practices
45. Paddy Hispa : Dicaldispa armigera
(chrysomelidae: coleoptera)
Adults is a small bluish black beetle, measuring 5 mm in length
and is easily recognized by numerous short spines on the elytra
46. Symptoms of damage
Adults feed on chlorophyll by scraping the green matter and causing
white parallel streaks on the leaves or straight white lines on the
leaf surface
White patches along the long axis of the leaf
Grubs mine into the leaves between epidermal layer, such leaves
causes white blotches near leaf tips and finally dry up
47. Paddy ear head bug : Leptocorisa oratoria
(Alydidae; Hemiptera)
Adult is an active, greenish
brown coloured bugs with
slender body and prominent
legs and antenna and measuring
2-2.5cm in length and producing
pungent smell when touched
Egg: female lays eggs
on the leaf blade
in long rows of
10-20
They are reddish brown
in colour
I.P – 6-7 days
Pest generally appears on rice just before flowering
stage and continue until the panicle ripening stage
48. The nymphs are slender, elongated yellowish or greenish in colour and suck the sap
from milk grains N.P – 14-15 days
50. • Stage of attack:- Generally appears on rice just before the flowering stage
and up to milky stage
• Damaging stages:- Both adults and nymphs
• Nature of damage:- Suck the sap of the peduncle, tender stem
and milky grains, inserting their proboscis
• Symptoms:- Grains become chaffy; At the spot of the puncture,
the water soaked spots appear and become brown
with white center; The ear heads in infested fields show
the presence of many such chaffy grains and the quality
of the affected grain gets deteriorated.
Apart from rice, they also breed on other grasses.
51. Damaged grains caused by rice bug
The quality of the affected grain gets deteriorate
Symptoms of damage
The damage appears as a brownish spot on the grains
Such grains are chaffy, partially, entirely
