Biology and management of armyworm of cereals Mythimna separata walker

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1. Arjun Rayamajhi PLP 06M 2017 Department of plant Pathology Agriculture and Forestry University Rampur, Chitwan Assignment presentation on Biology and management of Oriental Armyworm of cereals Mythimna separata

2. Biology and management of Oriental Armyworm of cereals Mythimna separate Presentation outline 1 . Introduction 1.1 Biology 1.1.1 Systematic Position 1.1.2 Distribution 1.1.3 Host plants / species affected 1.1.3 Marks of Identification: 1.1.4 Nature of Damage 1.1.5 Life Cycle: 1.2 Management 1.2.1 Mechanical and Physical Control 1.2.2 Cultural Method: 1.2.3 Biological Method: 1.2.4 Chemical Method: 2. Conclusion

3. Biology and management of Oriental Armyworm of cereals Mythimna separate Introduction The Oriental armyworm, Mythimna separate (Walker) is a noctuid moth whose larval (caterpillar) stage is a serious pest of cereals, pasture and forage crops in Asia (Wright, & McNeil, 1988). Its Common names for the pest include: southern armyworm , sorghum armyworm , army caterpillar , ear-cutting caterpillar and paddy cutworm (Sharma & Davies, 1983 ).

4. Biology and management of Oriental Armyworm of cereals Mythimna separate Systematic Position Phylum – Arthropoda Class – Insecta Order – Lepidoptera Family – Noctuidae Genus – Mythimna Species – separata

5. Biology and management of Oriental Armyworm of cereals Mythimna separate Distribution In Nepal, their damages have been recorded in many parts of the country such as Palpa , Argakhanchi and Gulmi districts (Rana & Plumb, 1973), Kavre and Sindhupalchowk districts (Rana, 1975) and Nuwakot and Rasuwa districts (Joshi, 1978). Anonymous (1976) reported M . separata also epidemic to maize crops in Jumla , Humla , Bajhang , Lamjung, Rasuwa , Nuwakot , Syangja , Kaski , Nawalparasi , Chitwan, Makwanpur , Bara, Parsa , Sarlahi , Mahottari , Dhanusa , Kathmandu, Bhaktapur and Lalitpur districts. In Nepal, winter maize is more susceptible to this pest ( Shivakoti & K.C ., 1981).

6. Biology and management of Oriental Armyworm of cereals Mythimna separate Figure 1 Distribution of Mythimna separata in worldwide ( Source:CABI Plantwise )

7. Biology and management of Oriental Armyworm of cereals Mythimna separate Figure 2 Distribution of Mythimna separata in South Asia ( Source:CABI Plantwise )

8. Biology and management of Oriental Armyworm of cereals Mythimna separate Host plants / species affected Brassica rapa subsp. chinensis (Chinese cabbage) Brassica rapa subsp. oleifera (turnip rape) Brassica rapa subsp. rapa (turnip) Cyperus rotundus (purple nutsedge ) Echinochloa colona ( junglerice ) Echinochloa crus- galli (barnyard grass) Eleusine coracana (finger millet) Eleusine indica (goose grass) Hordeum vulgare (barley) Linum usitatissimum (flax) Nicotiana tabacum (tobacco) Oryza sativa (rice) Panicum antidotale (elbow grass) Panicum miliaceum (millet) Pennisetum glaucum (pearl millet) Pennisetum purpureum (elephant grass) Phaseolus (beans) Saccharum officinarum (sugarcane) Secale cereale (rye) Setaria italica (foxtail millet) Sorghum bicolor (sorghum) Sorghum halepense (Johnson grass) Triticum (wheat) Triticum aestivum (wheat) Urochloa mutica (para grass) Zea mays (maize) (Source: CABI plantwise )

9. Biology and management of Oriental Armyworm of cereals Mythimna separata Marks of Identification: The adult moths are stoutly build and pale brown in colour . Forewings are greyish yellow Hindwings are grey in colour with dark external margin . Antennae are thread-like. Mature larvae are 3–4 cm long and green to pink in colour and provided with longitudinal light grey to black stripes running along the entire length of their bodies. The head is brown to orange with an A marking .

10. Biology and management of Oriental Armyworm of cereals Mythimna separata Nature of Damage The caterpillars are damaging stage In early stages , the caterpillars feed on tender leaves in central whorl of the plant. Later stages , they are able to feed on older leaves . In case of severe attack, they defoliate leaves and the field looks as grazed by cattle. The army worm feeds during dawn and dusk period as it is shy of sunlight. Fourth and fifth instars larva are the major damaging stages and defoliate the maize crop ( Neupane et al., 1992). These larvae not only feed the leaves but also damage the inflorescences, ears, growth points and finally the grains and finally caused a heavy decline in yield (GC & Keller, 2013 ).

11. Biology and management of Oriental Armyworm of cereals Mythimna separata

12. Biology and management of Oriental Armyworm of cereals Mythimna separata Damage of rice plants by Mythimna separata

13. Biology and management of Oriental Armyworm of cereals Mythimna separata Life Cycle: Eggs : Eggs are laid in cluster , consisting of approximately 500 eggs The young caterpillars hatch from the eggs in 4-5 days .

14. Biology and management of Oriental Armyworm of cereals Mythimna separata Larvae : After hatching the caterpillars starts feeding on the leaves of the seedlings. Generally the caterpillars move in swarm from one field to the other. The caterpillars are fully grown in about 15 days and measures 3-5 cm in length.

15. Biology and management of Oriental Armyworm of cereals Mythimna separata Pupae: pupates in soil at a depth of 3–5 cm , but sometimes it may pupate under dry leaves or on the stubbles or fresh tillers. The pupae are yellowish brown and shiny , and pupal period varies from 10 to 13 days .

16. Biology and management of Oriental Armyworm of cereals Mythimna separata Adult: the life cycle is completed in about 30-35 days which is repeated several times each year.

17. Biology and management of Oriental Armyworm of cereals Mythimna separata

18. Biology and management of Oriental Armyworm of cereals Mythimna separata Management Mechanical and Physical Control Barriers can be constructed to divert migrating M. separata larvae. kerosene can be poured in M. separata's path. Egg masses or larvae can be h and-picke d from seedbeds or a young crop .

19. Biology and management of Oriental Armyworm of cereals Mythimna separata Cultural Method: Before planting: Avoid following rice after crops of maize; follow with a food or forage legume. Weed the field. During growth: Weed crops, especially removing grass species. Put ducks in the fields to find and eat the larvae at the base of the plants or in the soil. Place perches in the fields for insect-feeding birds to use. Alter water levels to drown pupae, and to limit spread of larvae between plants. After harvest: Plough the field after harvest, burying the stubble, preventing mature larvae from pupating, and to expose the pupae buried in the soil.

20. Biology and management of Oriental Armyworm of cereals Mythimna separata Biological Method: Ducks are often raised in rice areas and can be herded into damaged fields to feed on M. separata larvae . Introduction of Apanteles ruficrus , Sarcophaga orientaloides and Exorista fallax is quite helpful in controlling the destruction caused by the caterpillars since, these insects parasitise the caterpillars. Sparrows and crows act as predators of this pest.

21. Biology and management of Oriental Armyworm of cereals Mythimna separata Chemical Method: Spray of chlorpyriphos 20 EC @ 2.5 litres /ha or quinalphos 25 EC @2.0 litres /ha or @ 1.0 litres /ha or dichlorvos 76 SL 600 ml/ha on the paddy crop during evening hours Dusting of chlorpyriphos 1.5 % D @ 30 kg/ha controls this pest.

22. Biology and management of Oriental Armyworm of cereals Mythimna separata Conclusion The armyworm, Mythimna separata Walker is the potential insect pest of cereals, causes a severe damage on the vegetative and reproductive stages of these plant. Timely identification and adoption of proper management is key for minimizing the loss . M anagement by adopting a tool of integrated pest management is one potential option to reduce the pesticide in crop fields.