Rice case worm

Agro Eco System Analysis (AESA) based integrated pest management (IPM)of Case worm in Rice

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.

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