The document discusses the rice case worm, an insect pest that damages rice crops. It describes the worm's lifecycle and identification at different stages. The worm makes tubular cases on rice leaves as larvae feed. This causes whitening, stunting and yield loss to rice plants. The document recommends an Agro-Ecosystem Analysis based Integrated Pest Management approach to control the worm through cultural, mechanical, biological and chemical methods while minimizing environmental impacts. These include drainage, conservation of natural enemies like spiders and parasitoids, and using pesticides only as a last resort.

1. AESA based IPM in
Rice Case Worm
Jeevaraj T V

2. Rice case worm
Systematic Position
• Kingdom Animalia
• Phylum Arthropoda
• Class Insecta
• Order Lepidoptera
• Superfamily Pyraloidea
• Family Crambidae
• Genus Nymphula
• Species depunctalis

3. Rice Case Worm
Significance
• Major insect pest of regional significance
• In low lying and waterlogged areas of Eastern
India

4. Rice Case Worm
Identificattion: Adult
Moth is small, snowy
white, about 6mm long.
White wings are
marked with a few light
brown to black specks
and two or three sub
marginal brownish
yellow bands.
Wingspan of 15 mm.
Adults are nocturnal

5. Rice Case worm
Identification: Egg
Individual egg is circular, somewhat
flattened, and measures 0.5 mm in
diameter. It is light yellow and has a
smooth surface. Mature eggs are
darker and develop two purplish dots
representing the eyes of the larva.
Tiny eggs are laid at night on the
underside of leaves floating on water
and leave sheath in 1 or 2 adjacent
rows in batches of 10 to 20. A female
lays about 150 eggs

6. Rice Case Worm
Identification: Larva
Pale translucent green
with light brownish orange
head. About 1.2 mm long
and 0.2 mm across the
head. The caterpillar
undergoes six instars and
is characterized by the
presence of tubular gills
on its body.Full grown
larva up to 15 mm long.

7. Rice Case Worm
Identification: Pupa
The pupa is cream in
colour and about 5.5
mm long and 1.5 mm
wide. Mature pupa is
silvery white. Before
pupation the case is
attached to the leaf
sheath above the
water level and its
both ends are plugged.

8. Rice Case Worm

9. Rice Case Worm
lifecycle
The life cycle is
completed in about 35-
40 days
Adults live for 4 – 6
days. Eggs are hatched
in 2 – 6 days. Larval
period is for about 20
days. Pupal period lasts
for about 7 days.

10. Rice Case Worm
Damage Symptoms
Rice at the seedling and vegetative
stages is the preferred host. The
larvae cut leaf tips to make leaf
cases. Caterpillars feed on green
tissues of the leaves and leaves
become whitish papery. The white
epidermis appears ladder like
because of the back and forth
motion of the larval head during
feeding. Leaves are cut at right angle
as with a pair of scissors. If the leaves
are disturbed, the cases along with
larvae fall on water surface. Floating
of tubular cases on the water is the
characteristic symptoms of case
worm attack.

11. Rice Case Worm
Severity of damage
Commonly found in irrigated and rain fed
wetland rice fields with poor drainage. Damage
may result in patches of severe defoliation,
stunted growth and death of plants. Caseworm
occurs regularly in low populations but sporadic
outbreaks result in intense defoliation of plants
causing severe loss in early vegetative stage.
Rice plants can recover from the damage if there
are no other defoliators present. However
maturity may be delayed for 7 to 10 days.

12. Integrated Pest Management
• IPM is a knowledge-intensive sustainable
approach for managing pests by combining
compatible cultural, biological, chemical, and
physical tools in a way that minimizes
economic, health, and environmental risks
with the help of pest scouts

13. Rice Case Worm
Agro Eco System Analysis based
Integrated Pest Management
An approach employed by extension
functionaries and farmers to analyse field
situations with regard to pests, defenders, soil
conditions, plant health, climatic factors and
their interrelationship for growing a healthy crop
and take appropriate decisions on crop
management practices

14. Rice Case Worm
AESA based IPM: Ecological
Engineering
Human activity to effect habitat manipulation
and to enhance biological control for pest
management through cultural practices
informed by ecological knowledge rather than
on high technology approaches such as
synthetic pesticides and genetically engineered
crops.

15. Rice Case Worm
AESA based IPM: Basic components
• Plant health at different stages
• Plant compensation ability
• Pest and defender population dynamics
• Soil conditions
• Climatic factors
• Farmers’ past experience

16. Rice Case Worm
AESA based IPM: Principles
• Grow a healthy crop
• Observe the field regularly
• Plant compensation ability
• Understand and conserve defenders
• Insect zoo
• Pest defender ratio

17. Rice Case Worm
AESA based IPM: Methodology
• General field observation
To be initiated after 20 days of transplanting. In each
field select five spots randomly at least 5 feet inside
the border. At each spot select four hills randomly for
recording observations (Total 20 hills/field)
• Data recording and drawing (weekly)
Plant growth, crop situation, input costs,
• Group discussion and decision making
Pest defender ratio
• Chart preparation and presentation to the group
members

18. Rice Case Worm
AESA based IPM: Nursery Stage
• Water management. Nonflooded seedbed is
protected from caseworm attack
• Mix 100 ml kerosene in standing water.

19. Rice Case Worm
AESA based IPM: general cultural
practices
• Wider spacing (30 x 20 cm)
• Early planting could escape the peak activity period of
moth
• Planting older seedlings reduces the duration of
susceptible stage of crop
• Destruction of weeds around the paddy fields (weeds
acts as alternate hosts: Panicum, Eragrostis, Paspalum)
• Optimal dosage and split application of nitrogen
fertilizer could reduce caseworm’s abundance

20. Rice Case Worm
AESA based IPM: Vegetative Stage
Mechanical Control
• Dislodge the cases by passing a rope and drain
water. Collect the cases and destroy
• Draining out standing water from the field for
3-5 days will kill the larvae

21. Rice Case Worm
AESA based IPM: Vegetative Stage
Biological Control
• Snails are useful predators of eggs
• Trichogramma chilonis is a parasite of eggs.
Release @1 lakh/ha
• While foraging for algae, snails
such as Pila sp. and Radix sp.
may dislodge caseworm eggs from rice leaves

22. Rice Case Worm
AESA based IPM: Vegetative Stage
Biological Control
• The larvae of
hydrophilids (Hydrophilus affinis,
Sternolophus rufipes and Berosus sp) and dystiscids
(Laccophilus difficilis) are predators of the caseworm
larvae.
• Elasmus sps; Apalteles sps; Dacnusa sp (Braconid
wasp); Hormius sps parasitises the larval stages

23. Rice Case Worm
AESA based IPM: Vegetative Stage
Biological Control
• common red ant (Solenopsis geminata) attack the larvae
and pupae of the pest, especially when the infested rice
fields become dry
• Pediobius sps and Apsilops sps parasitises the pupal stage
• Spiders (Neoscona theisi, Argiope catenulata and Araneus
inustus, Oxyopes javanus, Pardosa
pseudoannulata,Tetragnatha nitens, Clubiona japonicola)
prey on the moth
• Dragonflies and birds eat the adults.
• Nuclear Polyhedrosis Virus is also a potential control agent

24. Biological Control : Spiders
Orb spider (Argiope catenulata)
Oxyopes sp
Neoscona theisi

25. Rice Case Worm
AESA based IPM: Vegetative Stage
Other methods
• 1 L of kerosene mixed with 25 kg soil and broadcast
in 1ha will kill larvae
• Protection of natural habitats within the farm
boundary for conserving natural enemies.
• Resort to chemical spray as a last choice (carbaryl
10% DP @25kg/ha) during vegetative stage.
• However, no varieties resistant to the pest have
been identified.