Biology and management of armyworm of cereals Mythimna separata walker
1. ARJUN RAYAMAJHI
PLP 06M 2017
DEPARTMENT OF PLANT PATHOLOGY
AGRICULTURE AND FORESTRY UNIVERSITY
RAMPUR, CHITWAN
Assignment presentationon
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
īą 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).
īą 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
īPhylum â Arthropoda
īĄClass â Insecta
īˇOrder â Lepidoptera
īĸFamily â Noctuidae
âĸGenus â Mythimna
īSpecies â separata
5. Biology and management of Oriental Armyworm of
cereals Mythimna separate
Distribution
īąIn 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).
īąAnonymous (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.
īąIn 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)
9. Biology and management of Oriental Armyworm of
cereals Mythimna separata
Marks of Identification:
īą The adult moths are stoutly build and
pale brown in colour.
īą Forewings are greyish yellow
īą Hindwings are grey in colour with dark
external margin.
īą Antennae are thread-like.
īą Mature larvae are 3â4 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.
īą The head is brown to orange with an A
marking .
10. Biology and management of Oriental Armyworm of
cereals Mythimna separata
Nature of Damage
īąThe caterpillars are damaging stage
īąIn early stages, the caterpillars feed on tender leaves in central whorl
of the plant.
īąLater 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.
īąThe army worm feeds during dawn and dusk period as it is shy of sunlight.
īąFourth and fifth instars larva are the major damaging stages and defoliate
the maize crop (Neupane et al., 1992).
īąThese 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).
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:
īąEggs are laid in cluster, consisting of approximately 500 eggs
īąThe young caterpillars hatch from the eggs in 4-5 days.
14. Biology and management of Oriental Armyworm of
cereals Mythimna separata
Larvae:
īąAfter hatching the caterpillars starts feeding on the leaves of the
seedlings.
īąGenerally the caterpillars move in swarm from one field to the other.
īąThe 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:
īąpupates in soil at a depth of 3â5 cm, but sometimes it may pupate
under dry leaves or on the stubbles or fresh tillers.
īąThe 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:
īąthe life cycle is completed in about 30-35 days which is repeated
several times each year.
18. Biology and management of Oriental Armyworm of
cereals Mythimna separata
Management
Mechanical and Physical Control
īąBarriers can be constructed to divert migrating M. separata larvae.
īąkerosene can be poured in M. separata's path.
īąEgg masses or larvae can be hand-picked from seedbeds or a
young crop.
19. Biology and management of Oriental Armyworm of
cereals Mythimna separata
Cultural Method:
Before planting:
ī Avoid following rice after crops of maize; follow with a food or forage
legume.
ī Weed the field.
During growth:
ī Weed crops, especially removing grass species.
ī Put ducks in the fields to find and eat the larvae at the base of the
plants or in the soil.
ī Place perches in the fields for insect-feeding birds to use.
ī Alter water levels to drown pupae, and to limit spread of larvae
between plants.
After harvest:
ī 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:
īąDucks are often raised in rice areas and can be herded into
damaged fields to feed on M. separata larvae.
īąIntroduction 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.
īąSparrows and crows act as predators of this pest.
21. Biology and management of Oriental Armyworm of
cereals Mythimna separata
Chemical Method:
īąSpray 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
īąDusting of chlorpyriphos 1.5 % D @ 30 kg/ha controls this pest.
22. Biology and management of Oriental Armyworm of
cereals Mythimna separata
Conclusion
īąThe armyworm, Mythimna separata Walker is the
potential insect pest of cereals, causes a severe damage
on the vegetative and reproductive stages of these plant.
īąTimely identification and adoption of proper
management is key for minimizing the loss .
īąManagement by adopting a tool of integrated pest
management is one potential option to reduce the
pesticide in crop fields.