1. INSECT PESTS OF MAIZE
R. Regmi
Assistant Professor
Department of entomology

2. Major insect pests
• Maize stem borer, Chilo partellus (Lepidoptera:
Pyralidae)
• White Grub, Phyllophaga rugosa/Holotrichia
spp./Anomala dimidiate (Coleoptera: Scarabaeidae)
• Rice Ear- cutting caterpillar, Mythimna separata
(Lepidoptera: Noctuidae)
• Flower Beetle, Chiloloba acuta (Coleoptera: Cetonidae)
• Wireworms, Agriotes spp (Coleoptera: Elateridae)

3. 1. Maize stem borer 2, 3. White grub
4,5. Rice ear cutting caterpillar, Armyworm 6. Pollen beetle

4. Minor insect pests
• Rice Grasshoper, Hieroglyphus banian (Orthoptera: Acrididae)
• Grey Weevil, Myllocerus undecimpustulatus (Coleoptera:
Curculionidae)
• Maize Cob worm, Helicoverpa armigera (Lepidoptera:
Noctuidae)
• Cutworm, Agrotis segetum / A. ipsilon (Lepidoptera: Noctuidae)
• Leaf folder, Marasmia trapezalis (Lepidoptera: Pyralidae)
• Flea beetle, Monolepta signata (Coleoptera: Chrysomelidae)
• Maize shoot fly, Atherigonna spp. (Diptera: Muscidae)
• Banded blister beetle, Mylabris phalerata (Coleoptera:
Meloidae)

5. Continue minor insects
• Pink borer, Sesamia inferens(Lepidoptera: Nocutidae)
• Green Horned caterpillar, Melanitis leda
ismene(Lepidoptera: Satyridae)
• Maize aphid, Rhopalosiphum maidis (Homoptera:
Aphididae)
• Field cricket, Brchytrupes portentosus (Orthoptera:
Gryllidae)
• Seed Bed Beetle, Heteronychus lioderes (Coleoptera:
Dynastidae)

6. Rice Grasshopper Helicoverpa
Cutworm Maize shoot fly

7. Maize aphid Armyworm
Banded blister beetle

8. Maize stem borer, Chilo partellus
(Lepidoptera: Pyralidae)
• Most destructive pests of maize and sorghum.
• Its caterpillar damage maize and sorghum by
boring into the stems, cobs or ear.
• The grown up caterpillar are about 20-25 mm
long and dirty greyish white with black head and
four brownish longitudinal stripes on the back.
• The adult are yellowish grey moths, about 25mm
across the wing when spread.

9. Life cycle:
• The insect breeds actively from March- April to October.
• The rest of the year it remains in hibernation as full grown larva in
maize stubble, stalks or unshelled cobs.
• The larva pupate sometime in March and emerge as moths in the
end of that moth or in early April.
• They are active at night, when they mate and lay eggs on the
underside of the leaves of various hosts plants, particularly the early
crop of maize.
• The eggs are flat oval, yellowish and are laid in overlapping clusters
each containing up to 20 eggs.
• A female lays over 300 eggs during its life span of 2-12 days and the
egg hatch in 4-5 days in summer.

11. Continue life cycle
• The young larva first feed on the leaves making a few shot holes and
then bore their way downward through the central whorl as it opens.
• More shot holes becomes visible, indicating an earlier attack and the
plant also shows dead heart.
• The larva becomes full fed in 14-28 days, passing through six stages
and after making a hole in the stem pupate inside it.
• The life cycle is completed in about 4-7 weeks and there are probably 5
generation in a year.
• The full grown caterpillar of the last generation hibernates in stubble,
stalks etc. and remain there till next spring.

12. Damage
• The damage is done by the caterpillars by
eating inside of the stem.
• Production of dead hearts, weakening of the
plants are the symptoms of attack of any stem
borer.

13. Management
• Destroying the stubble, weed and other alternate hosts of the stem
borer by ploughing field after harvest.
• Removal and destruction of dead hearts and destruction of infested
plants showing early pin hole damage.
• Destruction of crop residues and chopping and stem harbouring
diapauses larva could be effective.
• Clipping of lower leaves of maize (upto 4th )
• Release Trichogramma chilonis @one lakh per ha on 10-15 days old
maize field crop.
• Spray crop 2-3 weeks after sowing as soon as borer injury to the
leaves is noticed with either of Fenvalerate 20EC @100ml/ha,
Cypermethrin 10EC@100ml/ha or deltamethrin 2.8EC@200ml
using 150 liters of water.
• Use granular pesticide Furadan 3%G@12-15kg/ha

14. White grub, Phyllophaga rugosa (Coleoptera: Scarabaeidae)
 White grubs are the larva of scarb “chafer” beetles.
 They are creamy white in color, C- shaped with brown head with 3
pair of thoracic legs.
 Some species of white grubs (Phyllogphaga spp.) feed on roots of
maize plants.
 Root damage is manifested by wilting seedling, poor plant stands,
patches of tilted or lodged plants showing uneven growth.
 Injured plants can easily be pulled out from ground.
 The third instar is often the most damaging one and may be present
in the soil for longest time.
 The extent of damage and species composition varies from place to
place.
 The larva is the major damaging stage but adults also damage the leaf
during night time.

15. Life Cycle
 Generally, most beetles takes 3 years to complete their life cycles in
temperate regions but only 2 years in optimum soil temperature.
 Female white grubs lay the eggs in soil in pasture land or in fresh
dung.
 Hatching of egg takes place after 2-3 weeks.
 First instar larva begin to feed on organic matter after hatching, later
feed on plants roots.
 With cooling soil temperature, larva descends into the soil profile,
where they spend the winter.
 In the spring, larvae begin their upward migration as soil
temperatures increases.
 The larval period ranges from 9-21 months and pupal period is 3-6
months.

16. Management
• Different cultural practices such as ploughing, harrowing, hoeing,
flooding and fallowing of field.
• The use of well decomposed Farm yard manure (FYM).
• Light traps can be used for collecting adults beetles during night.
• Use of Metarrhizium and Beauveria based biopesticide (1- 1 kg of
Metarrhizium & beauveria mixed with 25 kg of FYM and kept for 8
days in shade. Using this during land preparation).
• In Highly affected area, use Chloropyriophos 10 G @ 1kg per Ropani
before sowing.
• Treat the seed before sowing with 12.5ml of Chorpyriphos 20EC per Kg
of seed.
• Kills the beetles by spraying 500g of carbaryl 50WP in 250 liter of water
per ha on preferred host like Zizyphus, Guava, Grapevine etc.
• Apply 30Kg of carbofuran 3G per ha in the soil at or before sowing.

17. Armyworm, Mythimna separate
(Lepidoptera: Noctuidae)
• The armyworm is a pest of graminaceous crops all over the
world mainly pests of maize, wheat, sugarcan, jowar,
bajara.
• The larva feed voraciously and migrate from one field to
another.

18. Life cycle:
• The adult moths of armyworm are pale brown.
• They live for 1-9 days and lay eggs singly in row or in
clusters on dry or fresh plants or on the soil.
• The eggs are round, light green when freshly laid and
turns pale yellow and finally black.
• The egg hatch in 4-11 days from March to May and in 19
days in December- January.
• Freshly emerged larva are very active, dull white and
later turn green.
• In the spring, the larval stage is completed in 13-14 days,
but in winter it is prolonged to 88-100 days.
• In the pre-pupal stage, the insect spins a Cocoon.

19. Continue life cycle
• The pre-pupal stage last 1-11 days during January to
May.
• Pupation usually takes place in the soil at a depth of
0.5- 5 cm, but it may also occur under dry leaves
among the stubble or fresh tillers.
• Generally, the larva before pupation seem to select
sites near the water channels.
• The pupal stage is completed in 9-13 days in May and
36-48 days in the winter months.
• The survival of the pupae depends on soil moisture.
• The population build up starts in the beginning of
March & increase with the rise of temperature in the
spring.

20. Damage
• In the early stages, they feed on tender leaves in the central
whorl of the plant.
• As they grow, they are able to feed on older leaves also and
skeletonize them totally.
• The grown up caterpillar throw out faecal pellets, which are
quite prominent.
• In case of a severe attacks by the armyworm, whole leaves
including the mid rib, are consumend and field look as if
grazed by cattle.
• The larva of all instars feed mainly on leaves.
• Fourth and older instars larvae cause the main harm, roughly
gnaw out and eating around the leaf blade and damaging
inflorescences, ears, growth points and grain in ears .

21. Management:
• Collecting and destroying the caterpillar.
• Spray 500ml of dichlorovous 85 SL or 3 Kg of carbaryl
50WP or 1 Lit of Quinalphos 25EC in 250 Liters of water
per ha.

22. Flower beetle, Chiloloba acuta
(Coleoptera: Cetonidae)
• They are pollen feeders and are common on
flowers and may occur under loose bark in debris.
• Flower beetle caused damage in rice, maize,
sorghum, millets etc.
• They also feed on the leaves, bud and flower.
• The main injury consists in feeding and destroying
blossom petals.
• If many beetles are present, their excrement
often discolor the blossom.

23. • The adult beetles are shiny metallic green and
appear sometimes red or deep blue.
• The are irregularly covered with hairs on the
upper side but more densely on the sides and
underside.

24. Life cycle:
• Female lays hundreds of tiny, oval eggs, usually on a
leaf or in rotten wood, which usually takes 4-10 days
to hatch.
• The larva pass through 3-5 instars, they vary in shape
and size depending on where they live and what they
feed on.
• They generally appears grub like with a well defined
head capsule, which may be highly sclerotised.
• The larvae of Chiloloba species feeds on trunks,
branches or twigs of dying plants.
• The pupal stage is usually found during the winter
period and adult emergence occurs in spring.

25. Management
• Hand collection of adults beetle
• Collection with help of sweep nets
• Spray 500ml of dichlorovous 85 SL 1 Lit of
Quinalphos 25EC in 250 Liters of water per ha.

26. Wireworms, Agriotes spp (Coleoptera: Elateridae)
• Wireworm is the common name of the larva of click beetle.
• The name ” click beetle” originates from the habit of clicking its body into the
air.
• The adult beetle are harmless feeding on pollen, however, the larva belongs to
the most destructive soil insect pests.
• They are important pests of potatoes and other crops including cereals & also
damage germinating seeds.
• Most adult are light to dark brown and dull, between 6 to 10 mm long and
about 2 mm wide.
• The body of the beetles is convex.
• The egg are white, nearly globe shaped about 0.5 mm in diameter.
• The larva are dark yellow up to 25mm long and 2 mm wide. The apex of the last
segment of the larval body is sharp pointed.
• The larva are hard, nearly cylindrical and shining as those in all the species.
• Pupae are white 9-12 mm long.

28. Life cycle
• The females lay eggs in cluster or singly on roots or into
soil at a depth of 3-15 cm.
• The total female fecundity amounts to 50-350 eggs.
• The larva develops during 3-5 years, molting 8-11times.
• Overwintering takes place at a soil depth of 20-50cm.
• The larvae prefer moist soils, As soils dry out, they migrate
in deeper soil layer.
• Larger larvae are able to starve several months.
• A generation lasts 3-6 years depending on food
availability and environmental conditions.

29. Continue Life cycle
• Plants in unploughed soil and grassland represents the
primary food source for wireworm.
• Therefore, problems arise when infested pastures are
ploughed and planted with crops.
• Because of their extended life cycle, wireworm
damage may persists for 2-3 years after.
• The most significant damage is caused to germinating
seeds and seedling during cold, wet springs.
• Wireworm injury is often associated with a small
feeding hole at the base of the plant, which may kill
the growing point and stunt plant growth.

30. Damage
• The wireworm feed on seeds, seedling and
underground parts of crops & weed.
• The wireworm are more harmful for the grain
cereals, especially for maize, sunflower, potato,
Solanaceous and Cruciferous vegetables,
carrot, beet, turnip etc.
• Wireworm cause shoot thining, stunting of
damaged plants and quality loss of tuber crops
like potato.

31. Management
• Crop rotation that include alfa-alfa and high
glucosinolate Brassica spp may help in management of
wireworm.
• Field drying and summer ploughing
• Flooding field with water at least for 2 weeks
• Use of wheat as trap crop while growing maize and
other cash crops
• Use of Metarrhizium and Beauveria based biopesticide
(1- 1 kg of Metarrhizium & beauveria mixed with 25
kg of FYM and kept for 8 days in shade. Using this
during land preparation).