Pests of maize

PESTS OF MAIZE
Presented by:
Ch.Naga Satyasri
M.Sc(Ag)-I year
2

Pests of Maize crop:
• Stem borer: Chilo partellus
• Shoot fly : Atherigona orientalis
• Pink stem borer: Sesamia inferens
• Corn worm: Helicoverpa armigera
• Aphid: Rhapalosiphum maidis
• Shoot bug: Peregrinus maidis
• Ash Weevil: Myllocerus sp
• Spider mites: Tetranychus sp
• Termites: Microtermes sp
• Army worms: Mythmnia separate
3

Maize pests by crop stage
Pest stage
Emergence Vegetative Silking/Tass
-eling
Grian filling
Maize thrips
Maize
leafhoppers
Armyworm
Corn aphids
Helicoverpa
Two spotted
mites
4

STEM BORER (Chilo partellus)
• Pyralidae; Lepidoptera
• Geographical distribution: This borer is
associated with the Gramineae of Australia, East
Africa, and Southeast Asia. Closely related species
occur in North America. It is absent in West Africa.
• Seasonal abundance: During dry season,the
larvae enter into dipause and found in harvested
stalks and stubbles left in field.
5

Biology
Larva:
• Dirty white with brown head having many dark
spots on the body.
Adult:
• Straw coloured with pale yellow grey forewings
with black specks along caudal margin.
• In males, hind wings are pale straw coloured and
in females, hyaline.
6

• Description and life cycle:
• The young stem borers are small, spotted, and
yellowish.
• When full-grown they are 20 to 25 mm long and
spouted, with coloured stripes along the back of
the body.
• Before developing into pupae, the larvae prepare
an exit for the adult by leaving intact at the end of
their tunnels only the thin exterior wall of the
stem.
• The straw-coloured or yellowish brown moths,
which are about 15 mm long, deposit white, scale
like eggs in overlapping rows, usually on the
underside of leaves.
7

• Nature of damage:
• The initial symptom of infestation on young
plants is rows of oval perforations in leaves of the
unfolding whorl.
• This damage is caused by the feeding of the
young larvae.
• As they develop, the larvae tunnel into the leaf
midribs, damage the growing point
(causing a condition referred to as "deadheart"),
or bore into the stem.
10

Elongated
windows
Bore hole Dead heart
11

• Management:
• ANGRAU Recommendations:
• Trichogramma chelonis cards 2 to 3 per acre.
• Carbofuran 3G @ 3Kg per acre.
• Other Recommendations:
• Destroying volunteer and alternate hosts eliminates
stemborer.
• Crop rotation with cotton, groundnut or sugarcane
most effective against stemborer.
12

• Resistant varieties:
• HQPM 1, DHM 117, HM4, HM5, Vivek hybrid 5,
HMM 1, PEHM 1,Pusa Composite 3, Pusa
Composite 4, Amar, Azad Kamal
13

Shoot fly (Atherigona orientalis)
• Muscidae– Diptera
• Host range:
Maize, Wheat, Italian millets, and grasses
• Seasonal abundance:
• The insect attacks the seedlings and late sown crops are
attacked badly.
• The attack is severe during July to October. Cloudy weather
favours multiplication of the insect.
• In rabi, early sown crop suffers more and hence sowing
should be delayed possibly.
14

Biology
• Adult fly is dark grey, like the common house fly
but much smaller in size, 6 & 4 dark spots on
abdominal segments of female & male respectively
(arranged in rows of two)
• Maggot are legless, tapering towards head, pale
yellow, small ( 10- 12 mm in length ).
15

Life cycle
• Eggs: Eggs are average 40 eggs are laid by a female
singly on lower surface of leaves & tender stem.
• Incubation period is of 2-3 days.
• Larva: larval period 10 to 12 days.
• Four larval instars are present.
• Pupa: Pupation in stem.
• Pupal period is about a week.
• Adult longevity is 12-1 4 days.
• Life cycle completes in 2-3 weeks.
• Several generations in a year.
• Carry over -The pest over winters in adult stage on
grasses.
16

Shoot fly
Growth stages
of shoot fly
17

Nature of damage
• Maggots on hatching from the eggs bore into the
central shoots of seedlings and kill the growing
point, producing "dead hearts".
• They feed on the decaying core of the shoots.
Subsequently on death of central shoot, plant gives
out tillers and plant gets bushy appearance.
18

Management
• Seed treatment with imidachloprid 70 WS 10 g/kg
of seeds.
• Plough soon after harvest, remove and destroy the
stubbles.
• Soil application of phorate 10%CG 10 kg/ha at the
time of sowing.
• Apply any one of the following insecticides:
• Methyl demeton 25 EC @ 2 ml/l
• Carbofuran 3%CG @20 kg/ha
20

• Dimethoate 30%EC @2 ml/lt
• Methyl demeton 25% EC @2 ml/l
• Phorate 10%CG @ 1 kg a.i/ha
• ANGRAU Recommendations:
• Carbofuran 3G @ 2okg/ha
21

CORN EARWORM (Helicoverpa
armigera)
• Lepidoptera; Noctuidae
• Geographical distribution:
• Helicoverpa armigera is widely distributed in
Asia, Africa, Australia, and the Mediterranean
Europe.
22

• Host range: cotton, pigeonpea, chickpea,
sunflower, tomato, maize, sorghum, pearl millet,
okra, Phaseolus spp., vegetables, tobacco, linseed, a
number of fruits (Prunus, Citrus, etc.), and forest
trees. In recent years, H. armigera damage has
been reported in carnation, grapevine, apple,
strawberries, finger millet, etc.
23

Identification of the pest:
Eggs - Spherical in shape and creamy white in colour,
laid singly
Larva - Shows colour variation from greenish to
brown.
• It has dark brown grey lines on the body with
lateral white lines
Pupa - Brown in colour, occurs in soil, leaf, pod and
crop debris
24

Adult:
• Light pale brownish yellow stout moth.
• Forewings are olive green to pale brown with a
dark brown circular spot in the centre.
• Hind wings are pale smoky white with a broad
blackish outer margin.
25

Life cycle
• The oviposition period lasts for 5 to 24 days, and a
female may lay up to 3,000 eggs, mainly at night
on leaves, flowers, and cobs .
• The egg incubation period depends on
temperature, and varies between 2 to 5 days
(usually 3 days).
• Duration of larval development depends not only
on the temperature, but also on the nature and
quality of the host plant, and varies between 15.2
days on maize to 23.8 days on tomato.
26

• The larvae pupate in the soil
• Pale colored adults are produced from pupae
exposed to temperatures exceeding 30°C.
27

Nature of damage
• Damage occurs in several forms, including foliar
damage to young corn, damage to tassels and silks
and direct damage to kernels.
29

Management
• Helicoverpa armigera populations in several
regions have developed resistance to pyrethroids,
carbamates, and organophosphates.
• Introduction of new compounds such as
thiodicarb, indoxacarb, and spinosad has helped in
overcoming development of resistance in
H. armigera to conventional insecticides.
31

Apply any one of the following on 3rd and 18th
day after panicle emergence :
• Carbaryl 10 D @25 kg/ha
• Malathion 5 D @25 kg/ha
• Phosalone 4 D @ 25 kg/ha
32

Pink stem borer(Sesamia inferens)
• Lepidoptera: Noctuidae
• Distribution: This species has been reported from
all over India.
• Host plants: Maize and sugarcane are the
cultivated hosts apart from 33 other species being
reported as alternate hosts.
33

Description:
• Adult are whitish to dark straw coloured with
white hind wings.
• Sexual dimorphism is conspicuous.
• The male moth is slightly smaller than the female
and has pectinate antenna.
• The female has filiform antennae.
• Larva is purplish pink dorsally and white in colour
ventrally with an orange red head capsule.
34

Biology
• Female moth lays more than 400 eggs in batches.
• They are laid between leaf sheath and stem in
rows of 2-3 or on soil surface near base of the
plant.
• They are creamy white to dark and naked.
• Egg period varies with season, 4-9 days in summer
and 9-25 days in winter.
• The caterpillars do not tend to congregate but
disperse early.
35

• Larval duration is for 3-4 weeks with 5-7 moults.
• Pupation usually takes place inside the larval
tunnel within the stem and pupal period varies
from 5-12 days in summer and 12-36 days in
winter.
36

Symptoms of damage:
• Newly hatched larvae remain in a group behind
the leaf sheath and begin chewing on the stemand
inner side of the sheath.
• Later some larvae migrate to neighbouring leaf
sheaths, while others penetrate the stem,
expelling a dust from within.
• Severe damage cause the stem to break.
38

• Also feed in the whorl, tassels, and ears.
• If larvae invade the whorl, unfolding leaves will
have rows of oblong holes.
• Moreover, because of wilt brought on by damage
at the base of the plant, the central leaves of the
whorl may be easily detached, a symptom of what
is referred to as "deadheart."
39

Management
• Pull out and destroy by burning dead hearts and
affected plant parts
• Placement of granules in central whorls as
detailed under sorghum stem borer
• Carbofuran 3G , Carbaryl 5G @ 12Kg/ha in the leaf
whorl thrice at 20, 30 and 40 days age of the crop.
41

• Homoptera: Aphididae
Distribution:
• This insect is distributed worldwide.
Host plants:
• Jowar, bajara, other cereals and sugarcane.
Aphids (Raphalosiphum maidis)
42

• Marks of Identification:
• Aphids-Adults are minute, soft bodied, oblong, light green
or pale yellow Cornicles.
• They are characterized by the presence of 2 tubes like
structures on the dorsal side of abdomen.
• They are generally wingless but winged forms are often
noticed usually in the beginning and towards end of season
for migration to other crops.
• Nymphs: Smaller and greenish. Aphids are found in large
numbers on lower surface of leaves and leaf whorls and do
not move unless disturbed.
43

• life cycle:
• The small greenish blue adult females do not lay
eggs but give birth to living nymphs.
• In crowded colonies winged forms are produced
that eventually migrate to other plants.
• Skins that have been shed give the colonies a
whitish appearance.
45

• Both nymphs and adults suck the sap from plant
especially from the leaves.
• As a result the leaves turn yellow and in case of
heavy infestation the plants remain stunted.
• Their injury causes oozing of sap which
crystallizes on evaporation forming sugary
material called "Sugary Disease“.
• Due to sugary material oozing out of the plant and
honey due excreted by the insects, the sooty
mould develops and the leaves turn blackish.
• The yield is adversely affected and the fodder
quality also deteriorates
46

Management
• Coccinellids and chrysopids suppress the
population in nature.
• However, need based treatments with dimethoate
2 ml/l or monocrotophos 1.6 ml/l or
acephate 1 g/l are recommended.
48

Maize shoot bug
(Perigrinus maidis)
• Adult and nymphs suck the plant sap, which causes
reduced vigour, stunting and yellowing of leaves.
• The infestation prior to boot leaf stage usually causes
girdling/twisting of top leaves which, prevents panicle
development and emergence.
Management:
• Crop rotation with cotton, ground nut or sugarcane.
• Spraying of insecticide like Dimethioate 35EC @
2ml/lit
49

Two spotted Spider mite(Tetranychus
utricae)
• Arachnida: Tetranychidae
• On the underside of damaged leaves, one can observe
tiny green to reddish brown mites protected by a
delicate web secreted by the adults whose eggs have a
pearl-like appearance
• Development includes one translucent six-legged
larval stage followed by two eight-legged nymphal
stages. Imature feed on plant foliage just as adults do.
51

• Mites (which are more closely to spiders than to
insects) go through a larval and two nymphal
instars and multiply very quickly in hot, dry
weather
• Adults are tiny about 0.016 inch with four pairs
of legs. They range in colour from greenish
yellow to dull orange with two irregularly shaped
black spots, one on either side of abdomen.
52

• Mites can damage maize from the seedling stage to
maturity.
• The presence of small, faint, yellow blotches on
the lower leaves is an indication of spider mite
injury, wnich is inflicted through piercing and suc
king of the foliar tissue.
• As the colonies of mites increase in size,they cause
the lower leaves of the maize plant to become
dry,the mites then migrate to the upper leaves.
54

Management
• Spider mites are difficult to manage because of
their rapid outbreak.
• The only cultural practice that can help is to keep
weeds down around fields.
• Foliar sprays of wettable sulphur 3 g/l or dicofol 5
ml/l are found effective.
55

Adult - Grey coloured weevil.
Symptoms of damage:
• larva feeds on the secondary roots and adults on leaves.
Management:
• Spray quinalphos 25 EC @1 lit/ha or carbaryl 50 WP @1 kg
(500 l of spray fluid/ha).
Ashweevil: Myllocerus sp.,
56

Leafhopper: Pyrilla perpusilla
Nymph - Soft, pale brown dorsally and pale orange
ventrally
Adult - Straw coloured, head pointing forward as a snout
Symptoms of damage:
• Leaves become yellow
• Covered with black sooty mould
• Top leaves get dried up and lateral buds germinate
57

Management:
• Avoid excessive use of nitrogenous fertilizers
• Set up light trap
• Detrash: 150 and 210th DAP
• Release lepidopteran parasitoid:
• Epiricrania melanoleuca @8000 -10,000 cocoon /ha (or) 8 - 10 lacs
egg/ha.
• Spray any one of the following on the 150th and 210th day (1000 l
spray fluid)
▫ Malathion 50 EC @2000 ml
▫ Monocrotophos 36 WSC @ 2000 ml
58

Termites(Microtermes spp)
• These soft-bodied insects, often referred to as
"white ants," occur in various forms.
• The sexual forms, the "queen" and her cohort,
have four wings extending beyond the abdomen,
which are lost after pairing.
59

• Once the queen is established in a nest, her
abdomen becomes enlarged, and she produces
thousands of eggs, from which nymphs emerge.
• These either become soldiers, which protect the
termite colony, or workers, whose function is to
feed members of the colony.
• Both of those forms are sterile
60

• Termites occasionally cause partial or total
defoliation of maize seedlings but are principally
damaging to maturing or mature plants.
• After about three months of plant growth, termites
begin to attach the main root system, prop roots,
and stems and eventually pack the stems with soil
and cover them with galleries or tunnels made of
thin sheets of soil .
62

• As plants mature the amount of damage increases
rapidly and so does the likelihood of lodging,
brought about directly by termite injury or by
wind.
• Severely damaged plants may lodge and be
completely destroyed by termites. The longer a
field has been cultivated, the greater will be the
yield losses caused by these insects.
63

Management:
• Locating termitarium, digging out queen and
destroying is the only permanent remedy.
• Fumigation of ant hill with carbon disulphide or
chloroform mixture
• Destruction of crop residues which form sources
of infestation
• Seed treatment with chlorpyriphos @ 6 ml/kg of
seed
• Soil application of chlorpyriphos 50 EC @ 10 ml/l
as a soil drench at sowing time in termite prone
soils.
65

Army worms
(Mythimna seperata)
• The larvae feed on leaves leaving only mid ribs.
• Feeding takes place during the night time and hide in
the plant whorls or under the cover of vegetation.
• They migrated from one field to another when the food
was exhausted , hence called as army worms.
• Spray Monocrotophos 35 WSC @1.6ml/lit or phosphomidon
85EC@ 1ml/lit of water.
66

Grasshopper(Melanoplus spp.)
• Nymphs and adults will feed on corn in any
plant growth stage.
• The outer rows of corn are usually the first
attacked, but as the grasshoppers reach the adult
stage they move further into the field eating the
leaves, silks (may interfere with pollination), and
ear tips.
• When grasshopper populations are high and
damage is severe, they may only leave the leaf
mid-ribs, pruned ears, and barren stalks.
68

Management
• Scraping field bunds and summer ploughings to
destroy eggs, dusting cabaryl 10D or malathion
5D @ 10 kg/ac or foliar spraying with
fenitrothion 2 ml/l found effective in their
management.
70

IPM in Maize
• Cultural Practices
• Deep summer ploughing followed by fallowing helps in
exposing resting stage of pests.
• Inter-cropping with legume reduces borer incidence.
Maize-Soybean/Maize-Cowpea/ Maize- Green gram are
some of the good examples.
• Use of well decomposed farm yard manure (FYM)
reduces termite attack.
• Plant spacing 75 cm x 18 cm in kharif and 60 cm x 18 cm
in rabi is recommended.
• Balanced use of fertilizers (NPK 120:60:40) kg/ha and
supplement of micronutrient
71

• Genetic management:
• Use of resistant varieties like HQPM 1, DHM 117,
HM4, HM5, Vivek hybrid 5, HMM 1, PEHM 1,
• Pusa Composite 3, Pusa Composite 4, Amar,
Azad Kamal aginst stem borer.
72

• Mechanical practices:
• Removal of dead hearts will help to reduce
second generation infestation.
• Use of bird scarer prevents seed damage.
73

• Biological control:
• Conservation of naturally occurring biocontrol agents
such as Trichogramma chilonis , flavipes Cameron,
Carabids, Coccinellids, Chrysoperla, spiders and wasps,
etc. and by reducing chemical pesticides.
• Release of Trichogramma chilonis @ 1,60,000 /ha. on 7
and 15 days old crop and subsequently if required.
74

• Chemical control:
• Need based and judicious application of
pesticides is an important components of IPM.
• Granular application of Carbofuran 3% CG
@3kg/acre in whorls of infested plants to control
stem borer, shoot fly.
• Spray Monocrotophos 36% SL @ 1.6 ml/l or
Dimethoate 30% EC @ 2 ml/l or Oxydemeton –
methyl 25% EC or Phorate 10% CG @ 1 Kg
a.i/ha for the management of shoot fly.
75

Non insect pests
Birds:
• Important non-insect pests of maize.
• Large flocks of the birds can cause tremendous amount
of damage.
• Damage is often most prevalent along field edges and
nearby wooded areas, but can extend throughout a ,large
field.
• The symptoms that immediately catch the eye are
missing or damaged kernels on the cobs.
• Damaged cobs often turn brown or black once molds
begin infecting the damaged tissue.
76

Type of Damage by birds:
•Crop damage occurs at various stages of crop production due to
birds i.e. seeds may be removed after sowing, seedlings may be
pulled out, grains in milky stage or at the ripening stage may be
fed upon under uprooted conditions.
•The pigeons and crows inflict the damage at the germination
and seedling stages.
•The birds pick up the seed from the field after the post sowing
irrigation and feed on the soaked seeds which were in the
process of germination.
79

•They also pluck out on the developing young seedlings.
•At the flowering stage, the Rose ringed parakeets infest the
male inflorescence of maize (Tassel) and feed on the anthers
and pollen grains.
•At the tender maize cob stage, the parakeets damage the cobs
with the silky style and green husk.
•At milky stage of the maize cob when they split and strip
away the covering bracts there by exposing the grain for easy
feeding and further damage.
80

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