pests of cereals

Pests of cerealsPresented by:Anirudh Acharya .R. III Semester, M.Sc Zoology.

PESTS

Not pests – Damage < 5%

Minor pests – Damage is 5-10%

Major pests – Damage > 10%

Cereals

• Cereals – Monocot – Food grains.• Common food grains:• • Millet

Rice Wheat Maize

Major pests of RiceCommon name Scientific name Order

Stem borer Scirpophaga incertulas

Lepidoptera

Leaf folder Cnaphalocrocis medinalis

Lepidoptera

Brown Plant-hopper Nilaparvata lugens Hemiptera

Whorl maggot Hydrellia spp Diptera

Gall midge Orseolia oryzae Diptera

Hispa Dicladispa armigera Coleoptera

Yellow stem borer (Scirpophaga incertulas)

Distribution: The yellow stem borer of rice attacks only rice and has wide distribution in all Asian countries.

Nature of damage: Larva feeds inside the stem causing drying of the central shoot called ‘dead heart’ in young plant or drying of the panicle called ‘white ear’ in older plants.

October-December has been found conducive for the multiplication of the insect.

15 - 18 eggs on leaf shoots

Incubation period ranges from 5 - 8 days

2 – 3 days in leaves

Full grown: 33 - 41 days 20 mm long in stem.

It is dark brown and measures 12 mm long. The pupal period varies from 6 -10 days

50 - 70 days

Brown plant hopper (Nilaparvata lugens) Distribution: Distributed throughout South and South East Asia where rice

is grown. It is known only to feed on rice and the weed Leersia hexandra Sw., Poaceae.

Nature of damage: Both nymphs and adults are pests.

Plants turn yellow and dry up rapidly.

Early infestation - Round yellow patches appear, which soon turn brownish due to the drying up of the plants and this condition is called ‘hopperburn’.

N. lugens is a phloem feeder.

Very high infestation causes lodging of the crop resulting in yield loss ranging from 10 - 70 %.

• Life history: Two forms viz., macropterous (long-winged) and brachypterous (short-winged) are noticed and they are ochraceous brown dorsally and brown ventrally.

• The female inserts the eggs in two rows on either side of the midrib of the leaf sheath.

250 - 350

incubation period is 6 - 9 days

16 – 27 days

nymphal period 10 – 18 days

Major pests of wheatCommon name Scientific name Order

Grain aphid Sitobion avenae Homoptera

Shootfly Atherigona naqvii Diptera

Wheat Ghujia weevil

Tanymecus indicus Coleoptera

Army worm Mythimna separata Lepidoptera

Grain aphid (Sitobion avenae)

Distribution: This pest is found distributed worldwide in parts of Europe, Asia, Africa, North America, Central America and Caribbean and South America. In India it is reported from Delhi, Haryana, Himachal Pradesh, Jammu and Kashmir, Madhya Pradesh, Punjab, Rajasthan, Uttar Pradesh and West Bengal.

Nature of damage: A major pest of cereal crops in the spring.

Heavy infestations can cause a reduction of the number of grains.

Sooty moulds develop on the honeydew which they secrete.

This aphid is also a vector of the barley yellow dwarf virus (BYDV).

Life-cycle:

Primary hosts of this aphid belong to the genus Pubus and they are Polyphagous as well.

Shootfly (Atherigona naqvii) Distribution: Occurs in all wheat growing areas. Nature of damage: The maggots bore into the shoot

of young plants, a week after germination to about one month and as a result the central shoot dries up resulting in ‘dead hearts’.

If it is a little later the mother plant may produce side tillers. But the tillers also may be attacked.

The infestation often goes as high as 60%.

Life-cycle: The adult is a small dark fly. It deposits whitish eggs singly on the central

surface of the leaves.

The eggs hatch in 1 - 3 days and the maggots which are yellow in colour migrate to the dorsal surface of the leaf, enter the space between the leaf sheath and the axis and make a clean cut at the base of the leaf.

The growing point of the plant dies and decays on which the maggots feed. The larval period lasts for 6 - 10 days.

Pupation takes place inside the stem itself and the adults emerge in about a week.

Each female fly is capable of laying 30 eggs during its life time. Life cycle occupies 17 - 20 days.

Atherigona scotta

Major pests of SorghumCommon name Scientific name Order

Sorghum Shootfly Atherigona scotta Diptera

Sorghum midge Contarinia sorghicola

Diptera

Sorghum stem borer

Chilo partellus Lepidoptera

White Grubs Holotrichia consaguinea

Coleoptera

Sorghum midge (Contarinia sorghicola)

Distribution: It has a world wide distribution and is considered to be one of the important pests of sorghum.

Nature of damage: The maggots feed on the developing grains and cause the developing grains to shrivel and severe infestation has a significant effect on the overall production of grains.

The loss varies from 20 - 50 %.

Life-cycle:

It emerges between the tip of the glumes leaving the white pupal case attached to the tip in a characteristic manner.

It feeds inside the developing grain and pupates there itself.

14 - 90 days

White grubs (Holotrichia consanguinea)

Nature of damage : Cuts roots and several plants die in standing crop rows. It bores and damages groundnut pods.

Life-cycle: Adult : Beetles congregate in trees like

neem, acacia and feed on foliage. Eggs : Lay eggs in compost dumps /

manure pits. Larva : White ‘C’ shaped larva with

reddish brown head feeds on roots of crops.

Pupa : Pupates in soil.

Major pests of Maize:Common name Scientific name Order

Stalk borer Chilo partellus Lepidoptera

Pink borer Sesamia inference

Lepidoptera

Shoot fly Atherigona soccata

Diptera

Summary: Pests may be polyphagous or monophagous.

They may be periodic or non periodic.

They may even act as vectors for crop diseases.

Various control measures are employed.

References: Navarajan, P.A.V. Entomology – Insect pest and their

management. Indian Agricultural research Insititute 2007, New Delhi. Pg: 3-10

Reddy, K.V.S & Zehr, U.B. Novel strategies for overcoming pests and diseases in India. New directions for a diverse planet – proceeding of the 4th International Crop Science Congress 2004, Australia. Pg: 1-8.

Integrated Pest management for Crops. GOI 2001, Faridabad.

Available at http://takingroots.in/ipm_white_grub. Available at

http://www.iaszoology.com/sesamia-inferens/.