Insect pests of maize, wheat & ragi 1

Identification of Insect pests of Maize, Wheat and Ragi and their damage symptoms

Identification Insect pests of Maize and their damage symptoms

More than 130 insect pests have been recorded causing damage to maize in India, Among these about half a

dozen insect pests are of economic importance

Maize shoot fly Atherigona orientalis Muscidae Diptera

Stem borer Chilo partellus Pyralidae Lepidoptera

Pink stem borer Sesamia inferens Noctuidae Lepidoptera

Maize cut worm Mythimna separata Noctuidae Lepidoptera

Cob worm/ Earworm

Helicoverpa armigera Noctuidae Lepidoptera

Aphid Rhopalosiphum maidis Aphididae Hemiptera

Shoot bug Peregrinus maidis Delphacidae Hemiptera

Major insect pests of Maize are

1.  Maize shoot fly: Atherigona orientalis (Muscidae: Diptera) Distribution : Uttar Pradesh, Andhra Pradesh, Tamil Nadu, Maharashtra, Karnataka. In South India it is a serious pest but it also appears on spring and summer maize crop in North India. Host range:  Maize, sorghum, ragi and bajra Adult : Small grey coloured fly. It attack mainly at seedling stage of the cropDamage symptoms: The tiny maggots creep down under the leaf sheaths till they reach the base of the seedlings and feeds on the young growing shoots resulting in “dead hearts”

Dead heart formation

Maize stem borer: Chlio partellus ( Pyralidae : Lepidoptera)

Major pest of maize in India is called as Stalk borer Chilo partellus, that occurs during monsoon season and is a major pest throughout the country.

It is also most destructive pest of maize and Sorghum in India, Srilanka, Pakistan , Afghanistan, Uganda, Central and East Africa

Alternate hosts : This Insect has also been recorded on Bajra, Sugarcane, Sudan grass and some other grasses

Adult moth

Caterpillar

Adult is a medium sized straw colored moth

Fore wings: are light brownish with a row of black dots on the apical marginHind wings : are pale white colour

Eggs : lays eggs 10-25 days after germination on lower side of the leaves. I.P- 2-5 days

Larva : Larva passes 5-6 instars, The larva yellowish brown with reddish brown head and prothoracic shield and measures 25mm long with series of black dots L.P-28-35 days

The larva of the Chilo enters in the leaf whorl and cause damage in the leaves

Pupa : It pupate inside the stem in a small chamber PP-8-15 days

Dead heart

Larvae bores in to the shoot and feeds on the internal tissues and causes typical ‘dead heart’ symptom

Dead heart

Upper part of maize plant dies due to the boring of the caterpillar in the stem

Bored hole

Pink stem borer : Sesamia inferens( Noctuidae : Lepidoptera)

Moth is medium sized stoutly built having straw coloured forewings with dark brown longitudinal streak in the middle of the wing

Hind wings are white in colour

Sesamia inference occurs during winter season particularly in peninsular India

Larvae congregate inside the leaf whorls and feed on the central leaves causing typical ‘pin holes’ and later bore into the central shoot and severe feeding results in drying of the central shoot called dead heart formation or dead heart symptoms in the early stage of the crop Bored holes are plugged with excreta

Caterpillar is smooth and pink coloured The full grown larvae measures about 2.5 cm.

• The moth is nocturnal and lays eggs in between stem and leaf sheath. The larvae of the Sesamia enter the plant near the base and cause damage to stem.

The larvae bores in to the central shoot

Larva bore into the central shoot and severe feeding results in drying of the central shoot called dead heart formation or dead heart symptoms in the early stage of the crop Bored holes are plugged with excreta

Dead heart

Cob worm : Helicoverpa armigera (Noctuidae : Lepidoptera)

Caterpillar feed on silk and later bores the cobs

Adult is a medium sized, brownish yellow moth, A prominent black spots on the fore wing and

Broad black patch on the outer margin of hind wing.

Caterpillars feeds on developing grains

Female moth is stout with a wing expanse of 40mm whereas male moths are smaller with 35 mm in wing expanse

Eggs are laid singly on the silk of the cob or on the tender leaves I.P – 2- 5 days

Caterpillars : are smooth, measures 3.5 to 4 cm long and variously coloured with white lateral longitudinal stripes

L. P – 21- 28 days

Pupa : Full grown larva pupate in earthen cocoon in the soil P.P – 5-8 days

Nature and symptoms of damage

The caterpillar feed for while on silk or tender leaves and later bores the cobs feeds on milky grains at the top of the cob and also feed partially on developing grains

Bored area of the cob is plugged with excreta

Caterpillars are also feeds on tender leaves for a short time

Caterpillar also feed partially on developing grains and bored holes are plugged with excreta

This bluish-green aphids are colonizing species on sweet corn, and may be especially abundant in the developing tassel and occasionally on the ear and flag leaves and suck the sap Large populations produce sticky honeydew, which supports black sooty mould

Maize aphids: Rhopalosiphum maidis ( Aphididae : Hemiptera)

Maize cut worm : Mythimna separata ( Noctuidae : Lepidoptera)

The adult is stout bodied, medium sized moth, greyish brown in colour On the fore wings we find 2 white spots and prominent vein in the wings Nature of damage Larvae feeds on tender leaves in the central leaf whorl of the plant. As they grow, feed on older leaves also.

Shoot bug:  Peregrinus maidis (Delphacidae: Hemiptera)

Distribution : Karnataka, Tamil Nadu, Andhra Pradesh and Madhya Pradesh Host range: Sorghum, maize, rice, millets

Damage symptoms: Adults and nymphs suck the sap from the plants The attacked plants become unhealthy, stunted and yellow.  The leaves wither from top downwards.  Panicle formation is inhibited and the plants die if attack is severe.  Honeydew secreted by the bug causes growth of sooty mould on leaves.

Maize leaf hoppers Cicadulina sp.

Cicadellidae Hemiptera

Phadka grasshopper Hieroglyphus nigrorepletus

Acrididae Orthoptera

Sugarcane Leafhopper

Pyrilla perpusilla Lophopidae Hemiptera

Red headed Hairy Caterpillar

Amsacta albistriga Arctiidae Lepidoptera

White Grubs Holotrichia serrata Scarabaeidae Coleoptera

Chaffer beetle Chiloloba acuta Scarabaeidae Coleoptera

Termites Odontotermes obesus

Termitidae Isoptera

Minor insect pests of Maize are

Maize leaf hoppers Cicadulina sp.(Cicadellidae : Hemiptera )

Both nymphs and adults suck sap from ventral surface the of leaves, inject toxins resulting in whitening of veins and chlorotic patches especially at the tips of leaflets, in a typical 'V' shape.

Heavily attacked crop looks yellow and gives a scorched appearance known as 'hopper burn'

Both nymphs and adults feeds on leaves and thus defoliate the plants

Grass hopper: Hieroglyphus nigrorepletus (Acrididae : Orthoptera )

Long horned grass hopper Conocephalus spp. (Tettigoniidae : Orthoptera )

Both nymphs and adults feeds on leaves and thus defoliate the plants

Sugarcane leafhopper: Pyrilla perpusilla (Lophopidae: Hemiptera)

( Refer under sugarcane)

Adult is a soft, straw coloured hopper with the head pointing forward as snout. Wings fold over the abdomen like hood; densely veined and transparent. Symptoms are yellow leaves, covered with black sooty mould; top leaves get dried up.

Red headed Hairy Caterpillar Amsacta albistriga Arctiidae :Lepidoptera

Adults are medium sized moths

Fore wings : are white with brown streak all over the wings and yellowish streak along the anterior marginHind wings : are white with black marking or spots

Seasonal occurrence It is active during June to August The caterpillars of this pest cause serious damage to the crop by completely defoliating the leaves during the kharif season.

Larva : passes 7 instars

Body covered with long dense reddish brown hairs, anteriorly and posteriorly black broad bands enclosed a reddish area in the middle

L.P – 25- 40 days

Pupa : The grown up larva burrow the moist soil and pupate in the earthen cell P.P – 9-10 days

The female moth lays its eggs in clusters on the under-sides of leaves and covers them with pale brown hairsEach female lays about 600-700eggs Maximum – 2300 eggs / female

I.P – 3-4 days

The newly hatched larvae feed gregariously by scraping the green matter or skeletonization on the under surface of the young leaves leaving upper epidermal layer intact Later feed voraciously on the leaves leaving the petiole and midribs and main stem of the plants They march from field to field in gregarious manner and affected field appear as if grazed by cattle

Nature and symptoms of damage

Caterpillar feed on the leaves

White Grubs : Holotrichia serrata( Scarabaeidae : Coleoptera )

Grub- c- shaped scarabaeiform form larvae

Adults feeds on the leaves and tender shoots Grubs feeds on the root and rootlets as a

results death of the plants

Adult is a reddish brown beetle measures about 20 – 25 mm in length They have lamellate type of antennae

Nature of Damage

Roots damaged by root grubs

Chaffer beetle : Chiloloba acuta ( Scarabaeidae : Coleoptera ) Adults feeds on maize pollen which adversely affects pollination in northern part of India.

Termites : Odontotermes obesus ( Termitidae: Isoptera )Termite is also an important pest in many areas and on the damaged plants usually find earthen sheetingTermite damage starts soon after sowing and continues till the growing stage. 

The leaves of damaged plants droop down which later wither and dry. Such plants are easily uprooted. 

Identification Insect pests of Wheat and their damage symptoms

Pink stem borer Sesamia inferens Noctuidae Lepidoptera

Jowar stem borer Chlio partellus Pyralidae Lepidoptera

Ear head caterpillar Helicoverpa armigera Noctuidae Lepidoptera

Termites Odentotermis obesusMicrotermes obesi

Termitidae Isoptera

Army worm Mythimna separata Noctuidae Lepidoptera

Aphids Macrosiphum miscanthi Aphididae Hemiptera

Green plant bug Nezara viridula Pentatomidae

Hemiptera

Short horned grass hopper

Cyrtocanthacris ranacea Acrididae Orthoptera

Wheat is comparatively less susceptible to insect pests in the field. However, in recent year about half a dozen pests have become quite serious and major constraints in wheat production. These insect pests are

Pink stem borer : Sesamia inferens ( Noctuidae : Lepidoptera)

Refer under Ragi

Jowar stem borer: Chlio partellus ( Pyralidae : Lepidoptera)

(Refer under Jowar)

Ear head caterpillar : Helicoverpa armigera ( Noctuidae : Lepidoptera )

Adults are medium sized, brownish yellow moth, A prominent black spots on the fore wing and

Broad black patch on the outer margin of hind wing.

Detail refer under Maize

Larva attack the crop at maturity stage and feeds on the grains in the ear heads

Termites : Odentotermis obesus ( Termitidae : Isoptera )

There are about 16 species of termites are found in India Among these , 2 species are important pests of wheat in India Odentotermis obesus Microtermis spp.These are social insects, comprising queen, king, soldiers and workersWorker – are small sized pale white soft bodied wingless insectsSoldiers - with powerful mandibles and are found under earthen sheeting in the damaging siteQueen termite, eggs and nymphs are found inside the termiteria or nestsReproductive forms are wingedWorker caste causing damage to crops Termites damage the wheat crop soon after sowing and near maturity. The damaged plants dry up completely and are easily pulled out. The plants damaged at later stages give rise to white ears. Termites are not season bound, when ever there is a depletion moisture they will affect crop

Wheat seedlings damaged by termites, Odontotermis obesus

Workers feed on the root and stem Wilting and dry up

of the crop

Workers are smaller sized pale white, soft bodied wingless insects

Earthen sheeting

Worker feed on the root and stem in all the stages of the crop and causing wilting and dry up and also causes chaffy ear head

Army worm: Mythimna separata ( Noctuidae : Lepidoptera)

Larvae feeds on tender leaves in the central leaf whorl of the plant. As they grow, feed on older leaves and also feed on ear heads

The adult is stout bodied, medium sized moth, greyish brown in colour

On the fore wings we find 2 white spots and prominent veins in the wings

Aphids: Macrosiphum miscanthi ( Aphididae : Hemiptera)

Adults are yellowish green aphids with cornicles on the abdomen The nymphs and the females look alike, except that the latter are larger

The nymphs and adults suck the sap from plants particularly from their ears and tender leaves

They  appear on young leaves or ears in large numbers during the cold and cloudy weather

The damage is particularly severe in years of cold and cloudy weather. A heavily manured, well-irrigated and succulent crop will harbour the pest for a longer period and suffer greater damage.

The losses due to aphids have been reported up to 36 %

Green plant bug : Nezara viridula ( Pentatomidae : Hemiptera)

Adults are oval , green in colour and posses 5 segmented filiform antennae

This is also found on Jowar, maize, Ragi, and it is not a major pest

Adult NymphBoth adults and nymphs found on ear heads and suck the juice from the tender grains and only few grains are chaffy.

Both nymphs and adults feeds on ear heads and on the leaves and thus defoliate the plants

Short horned grass hopper

Identification Insect pests of Ragi and their damage symptoms

I. Borer pests

Ragi pink stem borer Sesamia inferens Noctuidae Lepidoptera

Ragi white stem bore Saluria inficita Noctuidae Lepidoptera

II. Sucking pests

Ragi leaf hopper Cicadulina bipunctata Cicadellidae Hemiptera

Ragi Aphid Hysteroneura setariae Aphididae Hemiptera

Ragi root aphid Tetraneura nigriabdominalis Aphididae Hemiptera

III. Defoliators

Ash weevil Myllocerus discolor Curculionidae Coleoptera

Black hairy caterpillar Estigmene lactinea Arctiidae Lepidoptera

Red headehairycaterpillar Amsacta albistriga Arctiidae Lepidoptera

Ragi cut worm Spodoptera exigua Noctuidae Lepidoptera

IV. Ear head feeders

Ear head caterpillar Helicoverpa armigera Noctuidae Lepidoptera

Orange banded blister beetle Mylabris pustulata Meloidae Coleoptera

Major pests of Ragi are classified as

Ragi pink stem borer : Sesamia inferens ( Noctuidae : Lepidoptera )

Moth is medium sized stoutly built having straw coloured forewings with dark brown longitudinal streak in the middle of the wing

Hind wings are white in colour

Yellowish eggs laid in groups in between stem and leaf sheath I.P- 3-5 days

Larva pinkish to brown in colour with reddish brown head and full grown larvae measures about 2.5 cm L.P- 25-30 days

Pupa - in the stem, P.P-8-10 days

Larvae congregate inside the leaf whorls and feed on the central leaves causing typical ‘pin holes’ and later bore into the central shoot and severe feeding results in drying of the central shoot called dead heart formation or dead heart symptoms in the early stage of the crop. Bored holes are plugged with excreta

Nature and symptom of damage

Chaffy ear head in the later stages

Ragi white stem borer: Saluria inficita (Noctuidae : Lepidoptera)

Adult is a medium sized dark brown moth with a pale-white band along the costal margin of each forewing Hind wings are white in colour

A specific pest of ragi in South India

Symptoms of damage

A creamy white caterpillars found at the base of the tillers close to soil surface and attack the basal parts of the plants and bore into the stems close to the soil surface and cause dead heart symptomsLarva pupates inside the stem

Ragi leaf hopper : Cicadulina bipunctata (Cicadellidae : Hemiptera)

Adults are minute , wedge shaped white coloured hopper or greenish brown coloured hopper and measures 2-3 mm in length and posses 2 black spots on the vertex Legs are longer than the body and presence of2 or 3 rows of spines on the hind tibia

Symptom of damageBoth nymphs and adults suck the sap from the leaves producing white specks and later dries up

Ragi AphidHysteroneura setariae (Aphididae : Hemiptera)

Winged or Wingless aphids found in clusters on the ear head

Adults are soft bodied, brown or black coloured winged or wingless insects

Indentified by the presence of a pair of cornicles on the 5 or 6 abdominal segments

Found in clusters on the ear heads and on young leaves

Aphids found in clusters on Young leaves

Both nymphs and adults suck the sap from the leaves as a results yellowing of leaves and also excrete honey dew as a result development of sooty mould and plants are sickly appearance

Symptoms of damage

Ragi root aphid Tetraneura nigriabdominalis(Aphididae : Hemiptera)

This pest common in South India and It infests root system and infestation prevails up to flowering stage in irrigated ragi during May – July

Pest occasionally reaches the pest status

Adults are numerous, minute, soft bodied pale green coloured insects

Root aphid

Black ant attending on the Aphids for their honey dew secretion

Both nymphs and adults attack under ground parts of the plants, they suck sap from roots causing gradual wilting and drying of plants in patches

The black ant, Camponotus compressus can be seen attending on the aphids for their honey dew excretion and presence of the ants at the base of the tillers is a clear indication of root aphids infested plants

Symptoms of Damage

Ash weevil: Myllocerus discolor (Curculionidae : Coleoptera)

A small weevils about 1cm in length mottled brownish with small grey coloured patches on the elytra and a large patch on the thorax

Adults feed on leaf edge and cutting U shaped pattern and thus defoliate the plants Grubs feeds on the roots

Myllocerus weevils on ear heads

Black hairy caterpillar : Estigmene lactinea ( Arctiidae : Lepidoptera)

The adults are creamy white moths with characteristic crimson marks on the head and the body Hind wings are white with black spots

Caterpillers feed on leaves and ear heads

Ragi cut worm Spodoptera exigua(Noctuidae : lepidoptera)

Adults are medium sized, stout bodied dark brown coloured mothFore wings – pale brown with grey colouerd markingsHind wings – white in colour

Symptom of damage

Early instars larvae skeletonize the leaves by scraping the green matter and later instars feed on leaves and thus defoliate the plants

Red headehairycaterpillar

Amsacta albistriga

Caterpillars feeds on leaves and ear heads

Grass hopper species feeds on leaves

Ear head Caterpillar : Helicovepa armigera ( Noctuidae : Lepidoptera)

Larva attack the crop at maturity stage and feeds on the grains in the ear head

Adult beetles feed on pollen and flowers; common in southern India