Fall Armyworm is a pest that feeds on over 80 crops. It was first reported in Southern Karnataka in 2018 and can spread quickly over large areas through moth migration. There are two strains - the maize strain that feeds on maize, cotton and sorghum, and the rice strain that feeds on rice and grasses. The moths lay eggs in masses on plant leaves. The caterpillars feed on leaves and other plant parts, causing damage. At the economic threshold level of 20% damage at early crop stages or 40% damage at late stages, control measures like handpicking, use of Bt products or neem-based sprays should be taken.

1. Introduction to Fall Army worm
Dr. J. Diraviam
Senior Scientist and Head, ICAR Krishi Vigyan Kendra
Pulutheri Village, R.T. Malai(PO),Kulithalai(TK), Karur(DT) - 621 313.
Mobile: 9488967675 Email: skvkk@gmail.com; j_diraviam@rediffmail.com;
Website: www.skvkk.org FB: Icar KVK Karur

2. History of its entry
• The Fall army worm is found throughout
the western hemisphere from Southern
Canada to Chile and Argentina. Recently it
was also reported from Africa during 2016.
The pest was first recorded in Southern
Karnataka during May 2018. The first
report of the pest from Karur district was
recorded during August 2018.

3. Spread of Fall Army Worm in Africa

4. Reasons for its severity
• FAW consumes many different crops.
FAW is capable of feeding on over 80
different crop
• FAW spreads quickly across large
geographic areas. moths can migrate over
500 km, a flight of 1,600 km from the
southern U.S. state of Mississippi to
southern Canada in 30 hours has been
recorded.
• FAW can persist throughout the year.

5. Strains of Fall army worm
• FAW consists of two strains adapted to different
host plants. One strain (the “maize strain”) feeds
predominantly on maize, cotton, and sorghum
• The second (the “rice strain”) feeds primarily
on rice and pasture grasses (Dumas et al.
2015a).
• The two strains are morphologically identical
but differ in pheromone compositions, mating
behaviour, and host range. Matings between the
two strains result in viable offspring.

6. Host range
• The caterpillars are mainly found feeding
on young maize plants, but they can also
attack a range of other crops including
millet, sorghum, rice, wheat, sugar cane
and vegetables.

7. Damage Symptoms on Maize
• Caterpillars feed on various plant parts of maize such as
leaves, stem and cob.
• Early instar caterpillars feed on leaves and produce
characteristic row of holes like symptoms.
• As larvae grow, they feed from the edge of leaves
inwards resulting in torn appearance and moist sawdust-
like frass near the funnel and upper leaves are observed.
• The damage often results in extensive defoliation and
damage to the growing points (leaf whorls). Early feeding
can appear to be similar to other stem borers.
• Deep feeding in the leaf funnel may destroy developing
tassels. Caterpillars tend to enter through the side of the
ear and feed on developing kernels.

10. Life cycle
• The moths lay eggs as egg mass and one moth can
lay between 900 to 1500 eggs.
• Egg masses are laid on the undersides of the leaves.
• Caterpillars are seen on the undersides of leaves and
the whorl. They are light green to dark brown with
stripes down their bodies.
• Large caterpillars have an upside down pale Y-shaped
marking on the front and their second-to-last body
segment has four dark spots in a square shape.
• Larvae have six instars. The larva pupates in soil.
Total life cycle is completed in about one month.
• Adult moths are greyish brown in colour.

11. Egg mass

12. Larval growth stages and
identity marks; Pupa

13. Adult male moth identity

15. Maize growth stages

16. FAW stages in maize crop
• The first generation of FAW emerging at
the V2 stage could complete development,
pupate, emerge, mate, and re-infest the
maize crop at the maturity stage during the
same planting season.
• In many instances where FAW is endemic,
the maize crop can be often seen with
overlapping generations of FAW on the
same plant.

17. Growth stages of larva and amount of
feeding

18. Sampling

19. Sampling method
• Start scouting as soon as maize seedlings
emerge.
• Scout 10-20 consecutive plants in 5
different locations in the field and calculate
% of infestation

20. ETL based on the stage of crop

21. Economic Threshold Level (ETL)
• Decision point:
• At early whorl stage (knee high), take action
if >20% of plants are damaged.
• At late whorl stage (shoulder high), take
action if >40% of whorls are freshly
damaged.
• At tassel and silk stage, do not spray
pesticides.

22. Management as per CABI
• Handpick and destroy egg masses and caterpillars.
• Spray with:
• –– Neem-based products
• –– Biopesticide Bacillus thuringiensis varieties in the late
afternoon
• Spray into the whorl. Ensure you wear long sleeves and
trousers along with a mask, goggles, gloves and boots while
spraying because chemical pesticides can be toxic.
• Avoid spraying pesticides early in the crop cycle as this will
kill natural enemies that control the pest, and may not be
economical.

23. Thank you