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Stored grain pests and their identification
NATIONAL INSTITUTE OF PLANT HEALTH MANAGEMENT
Department of Agriculture, Cooperation & Farmers Welfare
Ministry of Agriculture & Farmers Welfare, Government of India
Rajendranagar, Hyderabad - 500 030, Telangana, India.
Hand book on
Stored grain pests and their identification
Authors
Dr. Mandali Rajasri
Dr. J. Alice R.P. Sujeetha
Dr. Chandra Shekhar Gupta
Smt P. Geetha
NATIONAL INSTITUTE OF PLANT HEALTH MANAGEMENT
(Department of Agriculture, Cooperation & Farmers Welfare)
Ministry of Agriculture & Farmers Welfare, Govt. of India
Rajendranagar, Hyderabad 500 030.
Published by
National Institute of Plant Health Management
Plant Biosecurity Division
Rajendra nagar, Hyderabad - 500 030
Telangana, India
NIPHM @ 2019
Contributors
Dr. Mandali Rajasri, Joint Director of PBD
Dr. Chandra Shekhar Gupta, Assistant Scientific Officer, PBD
P. Geetha, Senior Research Fellow, PBD
Edited by
Dr. J. Alice R.P. Sujeetha, Director of PBD
Designed by
G. Mahesh, Junior Research Fellow, PBD
Disclaimer
The content and photos has been taken from various sources and the information
was complied for the benefit of endusers
Preface
“A grain saved is a grain produced”
Poor grain storage and resultant storage losses have been a persistent
problem in India. According to FAO, produce worth $14 billion is
damaged annually. It is a paradox that millions go hungry in India
everyday while food goes to waste. Storage losses in India amount to
12 to 16 million metric tons of food grains each year, an amount that
the World Bank stipulates could feed one-third of India's poor. India
has been ranked at the 103rd position among 119 countries on the Global
Hunger Index, with the highest food insecurity. The high volume of losses, if reduced,
can generate significant value and address food insecurity.
The storage losses are affected by several factors viz., biotic (insect, pest, rodents,
fungi) and abiotic factors (temperature, humidity, rain). Among all the biotic factors,
insect pests are considered most important and cause huge losses in the grains. Losses
can be minimized by physically avoiding the entry of insects and rodents, and
maintaining the environmental conditions that avoid growth of microorganisms. The
knowledge of control points and identification of insect and other pests that cause
storage losses can help in reducing losses during the storage. Taking the timely
preventive actions for biotic and abiotic factors can be very effective in reducing the
storage losses. Hence, there is every need to improve the scientific storage of grains and
technical efficiency of the professionals involved in the maintenance of grain storage
management.
Considering the criticality of the losses caused by these pests, it is very important to
identify different stored grain pests attacking grains in storage environment. This
pocket guide designed to give brief information on biology, identification, life cycle,
commodities attacked and damage caused by different stored grain pests associated
with different food grains in India. However, it acts as a basic field identification guide
for the officers working in FCI, CWC, SWC, Seed certification officers, quality control
officers, grain marketing officers and civil supplies corporations etc.,
I appreciate the efforts of Dr. Rajasri Mandali, Joint Director (PP), Dr. J. Alice R.P.
Sujeetha, Director (PBD), Dr. C S Gupta, Assistant Scientific Officer and other NIPHM
staff involved for their sincere efforts in compilation of this handy and compact
publication which will be a ready reckoner for the officers working in warehouses,
traders, quarantine officers, researchers, students and other stake holders.
Director General
NIPHM
Contents
S.No. Name of the Pest Page No.
1. Introduction 1
2. Rice weevil - Sitophilus oryzae 2
3. Granary weevil - Sitophilus granarius 3
4. Khapra beetle - Trogoderma granarium 4
5. Lesser grain borer - Rhyzopertha dominica 5
6. Pulse beetle - Callosobruchus chinensis 6
7. Cowpea weevil - Callosobruchus maculatus 7
8. Angoumois grain moth- Sitotroga cerealella 8
9. Indian meal moth - Plodia interpunctella 9
10. Almond moth - Cadra cautella 10
11. Rice moth - Corcyra cephalonica 11
12. Red flour beetle - Tribolium castaneum 12
13. Confused flour beetle- Tribolium confusum 13
14. Groundnut bruchid- Caryedon serratus 14
15. Sawtoothed grain beetle - Oryzaephilus surinamensis 15
S.No. Name of the Pest Page No.
16. Longheaded flour beetle - Latheticus oryzae 16
17. Cigarette beetle - Lasioderma serricorne 17
18. Drugstore beetle - Stegobium paniceum 18
19. Maize weevil - Sitophilus zeamais 19
20. Rusty/Flat grain beetle – Cryptolestes ferrugineus 20
21. Psocids 21
22. Liposcelis bostrychophila 22
23. Liposcelis entomophila 23
24. Storage Mites 24
25. Acarus, Glycyphagus 25
26. Rodents 26
27. Black rat - Rattus rattus 27
28. Brown rat - Rattus norvegicus 28
29. The House Mouse, Mus musculus 29
30. Bandicoot rat - Bandicota indica 30
31. Bandicota bengalensis - Lesser bandicoot rat 31
Stored grain pest and their identification
N I P H M
Stored Grain Pests and their Identification
1
1
In India, post-harvest losses caused by unscientific storage,
insects, rodents, microorganisms etc., account for about 10
per cent of total food grains. The major economic loss
caused by grain infesting insects is not always the actual
material they consume, but also the amount contaminated
by them and their excreta which make food unfit for human
consumption. About 500 species of insects have been
associated with stored grain products. Nearly 100 species of
insect pests of stored products cause economic losses.
Losses of grain in storage due to insects are the final
components of the struggle to limit insect losses in
agricultural production. These losses can exceed those
incurred while growing the crop. Losses caused by insects
include not only the direct consumption of kernels, but also
include accumulations of frass, exuviae, webbing, and
insect cadavers. High levels of this insect detritus may
result in grain that is unfit for human consumption.
Introduction
2
Egg
Larva
Adult
Damage
Commodities attacked: cassava, wheat, rice, maize, jowar,
chickpea, barley, dried stored products, lentil, pea, rye, broad bean,
adzuki bean, mung bean and cowpea.
Identification: Adults 3-4 mm, dark brown to black , elytra each
with two dull orange spots, flight wing (under elytra) present,
thorax with circular shape punctures. These species are externally
identical and only be distinguished by examination of genitalia.
Larvae- apodus.
Life cycle:
Optimum 25 days at 30°C, 70% RH. Range 15-34°C maximum
population growth rate per month -25.
Eggs- laid singly in operated hole in grain then covered with
waxy plug.
Larvae- immobile, develop concealed within single grain.
Adult- on emergence leave ragged hole in grain, long-lived
feed, fly.
Damage: Both grub and adults cause the damage. Grains are
hollowed out; kernels are reduced to mere powder. S. oryzae starts
its attack in field itself. Adults cut circular holes. Dry heating takes
place during heavy infestation. Grains which float in water often
indicate larval damage.
2. Rice weevil - Sitophilus oryzae (Curculionidae: Coleoptera)
1
3
Egg
Larva
Adult
Damage
Commodities attacked: barley, wheat, dried stored products, rice,
jowar, chickpea, oats, sunflower, broad bean and maize.
Identification: Adult-3-4 mm, dark brown, oval, long legs, front of
head with long snout, elytra unmarked ,flight wings (under elytra)
absent, thorax, with oval –shaped punctures. Larvae apodous.
Life cycle:
Optimum 25 days at 300C, 70% RH range 11-340C. Maximum
population growth rate per month -15.
Eggs- laid singly in operated hole in grain then covered with
waxy plug.
Larvae- immobile, develop concealed within single grain.
Adults- on emergence leave ragged hole in grain, long-
lived, feed, cannot fly.
Symptoms of damage: Both grub and adults cause the damage.
Grains are hollowed out; kernels are reduced to mere powder.
Adults cut rectangular holes. Heating takes place during heavy
infestation, which is known as 'dry heating'. It can also cause
serious damage under hot conditions before populations die out.
Larval stages feed inside the grain on the kernels, leaving only the
hulls. Severe infestations can reduce stored grain to a mass of hulls
and frass.
3. Granary weevil - Sitophilus granarius (Curculionidae: Coleoptera)
1
4
4. Khapra beetle - Trogoderma granarium (Dermestidae : Coleoptera)
Egg
Larva
Adult
Damage
Commodities attacked: groundnut, cotton, dried stored products,
barley, rice, millets, sesame, sorghum, wheat, maize, cowpea,
chickpea, sunflower, bajra and broad bean.
Identification: Adult-2-3 mm, oval, hairy, elytra, unmarked or
light markings. Antennal club three to eight segments; segment
jointed symmetrically. Larvae– eruciform, oval, with bands of
hairs.
Life cycle:
0 0
Optimum-25 days at 33-37 C, 45-75% RH Range- 20-40 C, % RH
> 2% Maximum population Growth rate per month – 13.
Eggs- laid amongst commodity.
Larvae- mobile, cast skins left in infested material, survive
without food for years.
Adults- short lived, do not feed on commodity, do not fly.
Symptoms of damage: Adults are harmless. Grub damages the
grain starting with germ portion, surface scratching and devouring
the grain. It reduces the grain into frass. Excessive moulting results
in loss of market value due to insanitation caused by the cast skin,
frass and hair. Crowding of larvae leads to unhygienic conditions
in warehouses.Damage is confined to peripheral layers of bags in
bulk storage.
1
5
5. Lesser grain borer - Rhyzopertha dominica (Bostrichidae: Coleoptera)
Egg
Larva
Adult
Damage
Commodities attacked: oats, wheat, rice, maize, jowar,
chickpea, barley, chilli, coriander, turmeric, cassava, beans,
ginger, ground nut, lentil, black gram and mung bean.
Ident ificatio n: Adults – 3 mm, dar k r eddish-br own,
cylindrical in cross-section. Head bent downwards and
concealed. Tip of abdomen tapered, end of elytra curved
gradually. Larvae – scarabaeiform, legs fully developed.
Life cycle:
o 0
Optimum- 25 days at 34 C, 70% RH. Range- 20-38 C, >30%
RH maximum population growth rate per month-20.
Eggs- laid on commodity or in tunnels bored by adults.
Larvae- internal feeders producing lots of flour, immobile
when mature.
Adults- long-lived, feed and bore into commodity, fly.
Symptoms of damage: Grubs and adults cause damage and
are voracious feeders. Adults reduce the grain kernels to mere
frass. Grubs eat their way into the grain or feed on the grain
dust and are capable of attacking grain externally.
1
6
Egg
Larva
Adult
Damage
Commodities attacked: pigeonpea, chickpea, soybean,
lentil, black gram, mung bean, cowpea, hyacinth bean,
buffalo-bean, rice, pea, winged bean, wheat, vetch, cowpea,
moth beans and groundnut.
Identification: Adults are 2.0-3.5 mm long. The antennae are
pectinate in the male, and serrate in the female, elytra
patterned and do not fully cover abdomen. Inner ridge of
lower side of hind femur with or without spine. Larvae-
scarabaeiform, legs partly developed.
Life cycle:
0 0
Optimum-21 days at 32 C, 90% RH. Range – 18-37 C,
20-90% RH. Maximum population growth rate per month – 50.
Eggs- glued individually to pod or seed.
Larvae- on hatching bore directly into seed, develop
concealed within seed.
Adults- short lived, do not feed on commodity, fly.
Symptoms of damage: Grubs eat up the grain kernel and
make a cavity. Adults come out making exit holes.
6. Pulse beetle - Callosobruchus chinensis (Bruchidae : Coleoptera)
1
7
Egg
Larva
Adult
Damage
Commodities attacked: gum arabic tree, pigeonpea, chickpea,
soybean, lentil, black gram, mung bean, cowpea, rice, pea,
winged bean, wheat, vetch, cowpea, moth beans, groundnut and
wild sweet pea.
Identification: Adults – 3-4 mm, globular with long legs and
antennae, elytra patterned and do not fully cover abdomen. Inner
and outer ridge of lower side of hind femur each with spine.
Larvae- scarabaeiform, legs partly developed.
Life cycle:
0 0
Optimum-21 days at 32 C, 90% RH. Range – 18-37 C, 20-90%
RH. Maximum population growth rate per month – 50.
Eggs- glued individually to pod or seed.
Larvae- on hatching bore directly into seed, develop
concealed within seed.
Adults- short lived, do not feed on commodity, fly.
Symptoms of damage: Grubs eat up the grain kernel and make a
cavity. Adults come out making exit holes. Infestation may start in
the pods before harvest and carry over into storage where
substantial losses may occur. As adult emerged from the seeds
they leave behind neat circular holes in the seed, behind which is a
large cavity left by the larvae.
7. Cowpea weevil - Callosobruchus maculatus (Bruchidae : Coleoptera)
1
8
Egg
Larva
Adult
Damage
Commodities attacked: wheat, rice, maize, jowar, chickpea,
barley, bell pepper, coriander, black pepper, ginger, turmeric, oats
and weed e. colonum.
Identifica tion: Adults- labial palps long and strong curved
upwards. Forewing (5-6 mm) pale greyish-brown with single small
black spot in centre, two-thirds from base. Wings heavily fringed
with fine hairs, forewing tapered to apex, rear wing with finger-like
projection.
Life cycle:
o 0
Optimum- 30 days at 30 C, 75% RH. Range- 16-35 C, RH >30%.
Maximum population growth rate per month-50.
Eggs- laid on commodity.
Larvae- excavate cavity in grain, remain concealed there, make
neat hole (covered with silk) in grain surface prior to pupation.
Adults- exit through hole often leaving silken 'door, still
attached to grain, short-lived, do not feed, fly.
Symptoms of damage: Larvae damage grains, adults being
harmless. Grains are hollowed out. It attacks both in fields and
stores. In stored bulk grain, infestation remains confined to upper 30
cms depth only. Caterpillar enters the grain through crack or
abrasion on grain. It feeds inside and remains in a single grain only.
8. Angoumois grain moth- Sitotroga cerealella (Gelechiidae: Lepidoptera)
1
9
Egg
Larva
Adult
Damage
Commodities attacked: groundnut, wheat, rice, maize, jowar,
barley, prunus, dried stored products, oats, sunflower, walnut,
pistachio, almond, cocoa, milled cereal products, spices, beans,
lentils and chocolate.
Identification: Adults- labial palps point forwards. Forewing
(7-9 mm) bi coloured cream and reddish-brown. Larvae- 15
mm, unmarked creamy white, rim of abdominal spiracles evenly
thickened.
Life cycle:
o 0
Optimum- 30 days at 30 C, 75% RH. Range- 15-35 C, RH 25-
90%. Maximum population growth rate per month-60.
Eggs- stuck to commodity.
Larvae- external feeders produce silk webbing.
Adults- short-lived, do not feed on commodity, fly.
Symptoms of damage: Larva causes serious damage to ear and
grain of maize; contaminates the grain with excreta, cast skins,
webbings, dead individuals and cocoons; prefers to eat the germ
portion and hence grains lose viability. It feeds superficially but
may construct more than one silken tunnel.
9. Indian meal moth - Plodia interpunctella (Pyralidae : Lepidoptera)
1
10
Larva
Adult
Damage
Commodities a tta cked: grou ndnut, fig, soybean,
cotton, flax, cassava, wheat, rice, maize, jowar, barley,
dried stored products, oats, sunflower, walnut, almond,
cocoa, apricot and mango.
Identification: Adults- labial palps short and curved
upwards. Forewing (7-9 mm) grey with darker markings.
Larvae-15-20 mm, white to pink with black spots (base
of hairs), rim of abdominal spiracles evenly thickened.
Life cycle:
o 0
Optimum- 26 days at 30 C, 75% RH. Range- 17-37 C,
RH >20%. Maximum population growth rate per month-
60.
Eggs- laid on loose in commodity.
Larvae- external feeders produce silk webbing.
Adults- short-lived, do not feed on commodity, fly.
Symptoms of damage: Larva feeds on germ portion
leaving the rest of the kernel undamaged. In bulk
infestation its damage is limited to peripheral top layers
only. Web formation covers the bags, floor-space and
mill machinery thereby leading to clogging in mills.
10. Almond moth - Cadra cautella (Pyralidae : Lepidoptera)
1
11
Egg
Larva
Adult
Damage
Commodities attacked: cassava, nutmeg, wheat, rice, maize,
jowar, chickpea, dried stored products, cotton, apricot, sesame,
groundnut, bell pepper, maize and redgram.
Identification: Adults- labial palps; male – short, hidden by
scales; female- curved downwards. Forewing (78-13 mm) grey
with no markings. Males much smaller than females. Larvae-
15-20 mm, white, rim of abdominal spiracles evenly thickened
on one (rear) side.
Life cycle:
o 0
Optimum- 27 days at 30 C, 75% RH. Range- 17-37 C, RH
>20%. Maximum population growth rate per month-10.
Eggs- laid on loose in crevices in commodity.
Larvae- external feeders produce lots of silk webbing,
irregular holes bitten into attacked material.
Adults- short-lived, do not feed on commodity, fly.
Symptoms of damage: Larva is only responsible for damage. It
contaminates food grains with frass, moults and dense webbing.
In whole grains, kernels are bound into lumps upto 2 kg.
11. Rice moth - Corcyra cephalonica (Pyralidae : Lepidoptera)
1
12
Egg
Larva
Adult
Damage
Commodities attacked: groundnut, oats, brazil nut, barley,
walnuts, lentil, rice, beans, lima bean, pea, almond and rye.
Identification: Adults- 3-4.5 mm, flattened, parallel-sided,
reddish-brown. Gap between eyes – 33% of head width. Last
three segments of antennae as distinct club. Structure between
base of front legs widest at tip (like 'axe head'). Eye divided
number of facets at narrowest point – 2. Larvae- elateriform.
Life cycle:
0 0
Optimum- 20 days at 35-68 C, >70% RH. Range- 22-40 C, RH
>1%. Maximum population growth rate per month-70.
Eggs- laid on commodity.
Larvae- mobile external feeder.
Adults- long-lived, feed on commodity, fly.
Symptoms of damage: Grubs feed on milled products. Flour
beetles are secondary pests of all grains and primary pests of
flour and other milled products. In grains, embryo or germ
portion preferred. They construct tunnels as they move through
flour and other granular food products. In addition they release
gaseous quinines to the medium, which may produce a readily
identifiable acid odour in heavy infestations.
12. Red flour beetle - Tribolium castaneum (Tenebrionidae : Coleoptera)
1
13
Egg
Larva
Adult
Damage
Commodities attacked: oats, rice, maize, jowar, chickpea,
barley, bajra, groundnut, hemp, cassava, sunflower and rye.
Identification: Adults- 3-4.5 mm, flattened, parallel-sided,
reddish-brown. Gap between eyes – 50% of head width.
Segments of antennae gradually wider towards tip. Structure
between base of front legs widest at tip (like 'axe head'). Larvae-
elateriform.
Life cycle:
o o
Optimum- 25 days at 32.5 C, >70% RH. Range- 19-37.5 C, RH
>1%. Maximum population growth rate per month-60.
Eggs- laid on commodity.
Larvae- mobile external feeder.
Adults- long-lived, feed on commodity, do not fly.
Symptoms of damage: Grubs feed on milled products. Flour
beetles are secondary pests of all grains and primary pests of
flour and other milled products. In grains, embryo or germ
portion preferred. They construct tunnels as they move through
flour and other granular food products. In addition they release
gaseous quinines to the medium, which may produce a readily
identifiable acid odour in heavy infestations.
13. Confused flour beetle- Tribolium confusum (Tenebrionidae: Coleoptera)
1
14
Egg
Larva
Adult
Damage
Commodities attacked: groundnut, dried stored products,
african oil palm, cotton, beans, cocoa, indian tamarind and bajra.
Identification: Adults- 17 mm, globular with long legs and
antennae, elytra light brown and do not fully cover abdomen.
Femur of hind leg enlarged, with one large tooth and 11-12
smaller 'teeth' on lower edge. Larvae-scarabaeiform, legs partly
developed.
Life cycle:
o o
Optimum, 42days at 30-33 C, 70-90% RH. Range- 23-35 C.
Eggs- glued individually to pod or seed.
Larvae- on hatching bore directly into seed, develop
completely within seed but may pupate in flimsy cocoon
outside seed.
Adults- leave neat exit hole in seed, short lived, do not feed
on commodity, fly.
Symptoms of damage: Grub causes the damage. Circular hole
on fruits and seeds of tamarind both in tree and storage.
14. Groundnut bruchid- Caryedon serratus (Chrysomelidae: Coleoptera)
1
15
Egg
Larva
Adult
Damage
Commodities attacked: oats, wheat, rice, maize, sorghum,
chickpea, barley, dried stored products, neem, locust bean,
sunflower, millets, rye and broad bean.
Identification: Adults- 3 mm, dark brown to dark grey, highly
flattened, parallel-sided. Thorax with three longitudinal ridges.
Side of thorax with six tooth – like projections. Length of head
behind the eye. Larvae- campodeiform.
Life cycle:
o o
Optimum, 20 days at 30-33 C, 70-90% RH. Range- 20-38 C,
RH > 10%. Maximum population growth rate per month – 50.
Eggs- laid amongst commodity.
Larvae- mobile, external feeders.
Adults- long-lived, very active, walk long distances, feed
on commodity, fly.
Nature of damage: Adults and grub cause roughening of grain
surface and off odour in grain. Grains with higher percentage of
broken, dockage and foreign matter sustain heavy infestation,
which leads to heating of grain.
15. Sawtoothed grain beetle - Oryzaephilus surinamensis (Silvanidae: Coleoptera)
1
16
Larva
Adult
Damage
Commodities attacked: rape, grasses, dried stored
products, wheat, rice and maize.
Identification: Adults- 3 mm, parallel-sided, slender,
flattened, yellowish-brown. Eyes crescent-shaped from
side. Antennae with distinctive five-segmented club,
final segment narrower than preceding one. Larvae -
elateriform.
Life cycle:
o o
Optimum, 22 days at 35 C, 85% RH. Range- 25-40 C,
RH > 30%. Maximum population growth rate per month
– 10.
Eggs- laid amongst commodity.
Larvae- mobile, external feeders.
Adults- long-lived, feed on commodity, fly.
Symptom of damage: Both grubs and adults feed.
16. Longheaded flour beetle - Latheticus oryzae (Tenebrionidae : Coleoptera)
1
17
Egg
Larva
Adult
Damage
Commodities attacked: cinnamon, cumin, cassava, tobacco,
dried stored products, cocoa, ginger, groundnut, peppers,
safflower, turmeric, yam, sweet potato, rice, aniseed, wheat and
cowpea.
Identification: Adults- 3-4 mm, brown, globular. Antennae
long, segments saw-like, elytra smooth with fine hairs. Larvae-
scarabaeiform, legs fully developed.
Life cycle:
o o
Optimum- 26 days at 30 C, 70% RH, range- 20-38 C RH> 25%.
Maximum population growth rate per month-20.
Eggs- laid in crevices in commodity.
Larvae- internal feeders, immobile when mature.
Adults- active, short-lived, do not feed on commodity, fly.
Symptoms of damage: Grub causes the damage which made
circular, pinhead sized bore holes on processed tobacco.
17. Cigarette beetle - Lasioderma serricorne (Anobiidae : Coleoptera )
1
18
Egg
Larva
Adult
Damage
Commodities attacked: cinnamon, cumin, cassava, tobacco,
dried stored products, cocoa, ginger, groundnut, peppers,
safflower, turmeric, yam, sweet potato, rice, aniseed, wheat and
cowpea.
Identification: Adults- 3-4 mm, brown, globular, last three
segments of antennae form loose club, elytra with fine
longitudinal ridges and fine hairs. Larvae- scarabaeform, legs
fully developed.
Life cycle:
o o
Optimum- 40 days at 30 C, 60-90% RH, range- 15-34 C RH>
35%. Maximum population growth rate per month-8.
Eggs- laid in crevices in commodity.
Larvae- internal feeders, immobile when mature.
Adults- active, short-lived, do not feed on commodity, fly.
Symptoms of damage: Circular pinhead sized bore holes,
caused by grubs.
18. Drugstore beetle - Stegobium paniceum (Anobiidae : Coleoptera)
1
19
Egg
Larva
Adult
Damage
Commodities attacked: maize, cassava, wheat, rice, jowar,
chickpea, barley, dried stored products, lentil, pea, rye, broad bean,
adzuki bean, mung bean and cowpea.
Identification: Adults 3-4 mm, dark brown to black , elytra each
with two dull orange spot, flight wing (under elytra) present, thorax
with circular shape punctures. These species are externally identical
and only be distinguished by examination of genitalia. Larvae-
apodus.
Life cycle:
o o
optimum 25 days at 30 C 70% RH range 15-34 C maximum
population growth rate per month -25.
Eggs- laid singly in operated hole in grain then covered with
waxy plug.
Larvae- immobile, develop concealed within single grain.
Adult- on emergence leave ragged hole in grain, long-lived
feed, fly.
Damage: Both grub and adults cause the damage. Grains are
hollowed out; kernels are reduced to mere powder. S. zeamais starts
its attack in field itself. Heating takes place during heavy infestation,
which is known as 'dry heating'. Damage is distinctive; both adults
and larvae feed directly on the kernel. Larvae feed internally and
newly emerged adults leave a ragged exit hole and will also feed on
the damaged kernel. Maize weevil infestations produce heat and
moisture.
19. Maize weevil - Sitophilus zeamais (Curculionidae: Coleoptera)
1
20
Egg
Larva
Adult
Damage
Commodities attacked: cereal grain and products, other dried
material of plant origin, packaged and processed goods.
Identification: Adults- 1.5-2 mm, reddish-brown, highly
flattened, parallel-sided. Hair –like antennae, up to length of
body. A ridge runs from above each eye down side of thorax.
Species difficult to distinguish except by examination of
genitalia. Larvae- campodeiform.
Life cycle:
o o
Optimum- 21 days at 35 C, 90% RH. Range- 20-42.50 C, 40-
90% RH. Maximum population growth rate per month-60.
Eggs- laid amongst commodity.
Larvae- mobile, external feeders.
Adults- long-lived, walk with characteristic sway, feed on
commodity, fly.
Damage: Both larvae and adults feed on germ and endosperm.
Heavy infestations may cause grain to heat and spoil. Beetles
may spread fungal spores through grain.They are the main insect
pest of farm-stored cereals.
20. Rusty/Flat grain beetle – Cryptolestes ferrugineus (Laemophloeidae: Coleoptera)
1
21
Psocids are major problem for the effective protection of stored products worldwide.
Psocids are the smallest pests of stored commodities. Psocids act as nuisance pests or
contaminants of low economic importance. This ignorance has mostly been due to
the fact that damage to bulk commodities by these pests has always been
overshadowed by major pests, such as beetles. Among psocids, members of genus
Liposcelis are the most frequently encountered pests in grain storages on farm, export
terminals, warehouses with bagged commodities and even in kitchen pantries.
21. Psocids
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Feeding on Grains Adult
Lifecycle: Development occurs during the summer and lasts between 20 and 40 days;
Optimum conditions: At a constant temperature of 27°C and 65% relative humidity the
development lasts about 30 days, of which seven are the egg stage. Six to eight
generations can be produced in a year.
Identification: Adults 0.7 to 1mm.highly flattened, wingless femur of hindleg
enalarged, translucent to dark brown.
Commodities attacked: Any dried material of plant and animal origin especially of
slightly damp, a common pest of crop residue.
Nature of damage: Liposcelis are secondary pest which are able to excavate the soft
endosperm from the damaged and broken grain. They feed preferentially on damaged
grain germ and capable of completely eating out the germ. Psocids will also eat mould
spores and fungal hyphae.
22. Liposcelis bostrychophila (Liposcelididae, Psocoptera)
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Larva
Damage
Identification: Adults 1mm.highly flattened, wingless femur of
hindleg enalarged, translucent to dark brown.
Commodities attacked: Any dried material of plant and animal
origin especially of slightly damp, a common pest of crop
residue.
Optimum conditions: At a constant temperature of 18°C and
60% relative humidity the development lasts about 30 days, of
which seven are the egg stage. Six to eight generations can be
produced in a year.
Nature of damage: Liposcelis are secondary pest which are
able to excavate the soft endosperm from the damaged and
broken grain. They feed preferentially on damaged grain germ
and capable of completely eating out the germ. Psocids will also
eat mould spores and fungal hyphae.
23. Liposcelis entomophila (Liposcelididae, Psocoptera)
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Lepidoglyphus destructor
Tyrophagus putrescentiae
Mites as pests At least twelve mite species infest stored
grai n. The mo st c om mon ar e sp ec ies of A ca ru s,
Tyrophagus, Glycyphagus and Lepidoglyphus. Mites can
cause direct damage by eating out the germ and can taint
produce. The most serious effects potentially result from
allergens that mites contain or produce. Mites may also
transmit fungal spores and act as vectors of human
pathogens. Living and dead mites have been found in foods
ranging from biscuits to baby food. Such contamination is
causing increasing concern. Mites can survive inside grain
and populations build up quickly.
Life cycle: Females may lay up to 250 eggs in a month.
Some mites may also enter a highly resistant, non-feeding
resting stage known as a hypopus. Mites thrive in high
humidity conditions. Mites mainly feed on the germ. Mites
can subsist on organic debris in cracks, crevices and
corners of storage areas.
Optim um cond it io ns: M it es mu lt iply un der h ig h
humidity conditions (over 65% relative humidity) and
o
upp er te mperatu re limit of 3 5-37 C. Commodi ties
24. Storage Mites
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Commodities attacked: flour, grain, seeds and bulbs
and Also fungi that develop on these products.
Identification: Mites are pale, pearly or greyish white
and about the size pinhead. They have translucent ,soft,
wingless bodies with no pronounced demarcation
between body parts .The first two pairs of legs are widely
separated from the two hind pairs of legs. There are two
pairs of fairly long hairs trailing and the end of the body.
Damage: Both the mould and grain mites cause direct
damage by eating the germ of the grain and spreading
fungi in the commodities. Heavily infested commodity
becomes tainted with off-flavours caused by squashed
mite bodies when it is moved or processed. During heavy
infestation from the mould mite, the dead and live mites
settle as a brownish dust layer on stacks of commodities
and floors of stores.
25. Acarus , Glycyphagus
Acarus siro
Glycyphagus domesticus
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Rodents: Rats have been estimated to damage more than
1% of the world cereal crops and 3-5% in developing
countries. Rats consume about 25gm of food per day and
mice eat approximately 3-4 gm per day. They contaminate
a lot of the stored produce with urine, faces, hair and
pathogenic agents. Infested batches often have to be
declared unfit for human consumption. As rodents mainly
feed on the embryo, they cause particular damage to the
nutritional value and germination ability of seeds. Produce
leaking out of bags or containers. Bag stacks collapsing.
Droppings shape, size and appearance of droppings can
provide information as to the species of rodents and the
degree of infestation.
26. Rodents
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Identification: 16 – 24 cm in length, with a tail longer than the head and body.150 –
200g in weight. Pointed nose, large ears and a slender body when compared to the
Brown Rat (Rattus norvegicus).
Lifecycle: 5 – 10 young per litter; 3 – 6 litters a year. Gestation period of about 3 weeks.
12 – 16 weeks from birth to sexual maturity.
Habits: Appearance confined mainly to ports. Often climbs, agile, rarely burrowing
and rarely outdoors in India. Preferred food is moist fruits. Will eat around 15g of food
a day and drink 15ml.
27. Black rat (Rattus rattus) Black rats can be found only rarely in India.
Rattus rattus
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Brown rats usually prefer ground living and burrowing, but sometimes they can be
known to climb.
Appearance: Up to 40 cm in length, with a tail shorter than the head and body. 350 –
500g in weight. Blunt nose, small ears and a thicker body when compared to the Black
Rat (Rattus rattus).
Lifecycle: 7 – 8 young per litter; 3 – 6 litters a year. Gestation period of about 3 weeks.
10 – 12 weeks from birth to sexual maturity
Habits: Usually ground living and burrowing, but sometimes climbs. The only species
to occur in sewers in India. Preferred food is cereals. Will eat around 30g of food a day
and drink 60ml.
28. Brown rat (Rattus norvegicus)
Rattus norvegicus
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This species is also cosmopolitan, There are many subspecies and colour variations are
extreme: the fur dorsally is usually brown to brownish grey (although black and other
colours occur), and grey ventrally. The head+body length is 70-110 mm, and a fully
grown adult weighs 15-30 am. The tail is about as long as the head+body length. The
ears are quite large in relation to the rest of the body, while the feet are comparatively
small and the snout pointed.The house mouse is a good climber and lives in social
groups. It can be a serious pest in agricultural fields and buildings, but has also been
recorded in native or natural vegetation.
29. The House Mouse, Mus musculus
Mus musculus
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Bandicoot rat (Bandicota indica) is the largest, weighing 0.5 to 1 kg (1.1 to 2.2
pounds). The shaggy, blackish brown body is 19 to 33 cm (7.5 to 13 inches) long, not
including a scantily haired tail of about the same length. Greater bandicoot rats are
found on the Indian subcontinent. It is a serious pest in agricultural fields and
warehouses.
30. Bandicoot rat (Bandicota indica)
Bandicoot rat
(Bandicota indica)
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Bandicota bengalensis
(Lesser bandicoot rat)
Bandicota bengalensis (Lesser bandicoot rat) is 270 mm in head and body, the tail is
220 mm, dark in colour. Body weight is 250-600 g. The fur is coarse and rough looking
and the longer guard hairs are prominent. Animals range from brownish grey to almost
blackish. It is a serious pest in agricultural fields and warehouse.
31. Bandicota bengalensis (Lesser bandicoot rat)
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N I P H M
NATIONAL INSTITUTE OF PLANT HEALTH MANAGEMENT
(Department of Agriculture, Cooperation & Farmers Welfare)
Ministry of Agriculture & Farmers Welfare, Govt. of India
Rajendranagar, Hyderabad 500 030.