1. Insect Pests of Stored Grains and Pulses

3. Stored Entomology - The study of the insect pests of stored grains and pulses is called storage entomology.

4. Stored Grain Insect Pests These are of two types:
Primary Insect Pests or Internal Feeders which can damage all kinds of stored grains
Attack whole grains
Larvae feed and develop within the kernel
Secondary Insect Pests or External Feeders that attack only the broken kernel or milled grains(Feed on grain dust)
Can not damage whole grain
Follow internal feeders, i.e. damaged grain
Grain in poor condition, microbial activity.

5. Two Types Of Insects :
Beetles
Moths

6. Some of the pests are : MOTH : Rice Moth (Corcyra caphalonica)
BEETLES :
Pulse Beetle (Callosobruchus maculatus)
Rice Weevil (Sitophilus oryza)
Wheat Weevil (Trogoderma granarium)
Rust Red Flour Beetle (Tribolium castaneum)
Lesser Grain Borer (Rhizopertha dominica)
MOTH :
Rice Moth (Corcyra caphalonica)

7. Pulse Beetle (Callosobruchus maculatus) :

8. SYSTEMATIC POSITION
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Coleoptera Family: Chrysomelidae Genus: Callosobruchus Species: C. maculatus

9. DiSTRiBUTiON: First reported from china in 1758
cosmopolitan distribution, occurring on every continent except Antarctica

10. FEEdS ON :
It is a serious pest of stored grain as well as standing crop in the fields.
Feeds on pulses (cowpea or mung dal) or gram.
It also attacks practically all other pulses.

12. LiFE HiSTORY : Complete metamorphosis
Egg  Larva (Grub)  Pupa  Adult.
Chewing type of mouthparts.

13. Female lays clear, small, whitish eggs shiny, oval to spindle- shaped, and about millimeters long, singly on the stored seeds of the uppermost layer or on the green pods in a field.
Slender grubs emerge in 4-7 days.

15. They bore into the seeds or pods, feed voraciously and become full grown in 2-3 weeks in summer.
Full grown grub is 6mm. long, white, fleshy, heavily wrinkled creature.
Grub pupates within the seed .

17. The pupa is an oval, white structure.
Pupation takes about 4 days in summer, longer in winter.
The adults come out by cutting a circular hole in the cover and shift to the uppermost layers of the seeds.
They copulate immediately after emergence and female starts laying eggs the next day.

18. The life span of the adult varies from 5 to 20 days according to the climatic conditions.
There are 7 to 8 overlapping generation in a year.
Larva hibernates in winter.
The pulse beetle have tendency to shift to the fields after a few generation in the godowns.

19. GENERAL APPEARANCE :
The adult pulse beetle is a chocolate colored insect, about 3mm. long and also has two black spots.
It has relatively small head with blunt rostrum, long antenna with serrated inner margin, distinct prothorax with two white prominences, elytra not fully covering the last abdominal segment.

21. The beetle is sexually dimorphic and males are easily distinguished from females.
The females are sometimes larger than males, but this is not true of all strains.
Females are darker overall, while males are brown.
The plate covering the end of the abdomen is large and dark in color along the sides in females, and smaller without the dark areas in males.

22. DAMAGE :
C. maculatus is a serious pest of stored grain as well as standing crops in the field.
The grubs bore into the seeds and are mainly responsible for the damage.
Maximum damage occurs during April to October.
Entire contents of the seeds are consumed, leaving only testa behind.

23. The intensity of infestation depends on humidity and temperature.
Infested seeds become unfit for human consumption.
One or more circular holes about 1mm. wide in the seeds mark the exist of the grubs and indicate infestation.

24. CONTROL :
The beetle is considered "medically harmless" to humans. It is a damaging agricultural pest
The seeds should be exposed to sun for 3days in summer to kill the pests.
About 5cm. thick layer of sand spread over the seeds in summer will check egg laying.
About 25cm. thick layer of lime spread over the seeds in winter will check the damage effectively.

25. Rice Weevil (Sitophilus oryza)

26. SYSTEMATIC POSITION
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Coleoptera Family: Curculionidae Subfamily: Dryophthorinae Genus: Sitophilus Species: S. oryzae

27. DiSTRiBUTiON: All over the world.
It is native of India and a serious pest of rice here.

28. FEEdS ON :
Feed on rice grains, less commonly on wheat and maize grains.
Only skin of the grain is left behind.

30. LiFE HiSTORY : Complete metamorphosis
Egg  Larva (Grub)  Pupa  Adult.
Chewing type of mouthparts.

32. The female weevil lays glistening, oval, whitish eggs measuring 0.66X0.3 mm. from April to October in 1mm. deep holes in the grains made with mandibles.
Generally one egg is deposited in one grain, 2-6 eggs per day and up to 300 over their lifetime.
After laying, the hole is plugged with a gelatinous secretion.
Small, white, fleshy, legless larvae, called grubs, emerge in just 4 days in warm and in 6 to 9 days in cold months.

34. The grubs burrow deeper, where they feed and become full grown (5mm
The grubs burrow deeper, where they feed and become full grown (5mm. long) in 19 to 34 days.
They pupate within the grain for 6 to 14 days.
The pupa is at first dirty white, but later becomes dark brown.
The adult weevils start breeding as soon as they emerge from the grains.

36. They live for 4 to 5 months.
A single female lays about 250 eggs during her life 5 to 6 broods.
A complete life cycle takes about a month.
The duration of various stages varies with the weather conditions, especially humidity and temperature.

37. GENERAL APPEARANCE :
Adult rice weevils are able to fly, and can survive for up to two years
An adult weevil is a small, reddish-brown beetle, about 3mm. long and with a prominent curved snout bearing a pair of stout jaws at the tip.
Four light reddish or yellowish spots occur on the elytra.
Male is generally smaller than female.
The adult beetles hibernate in winter in cracks and cervices or under wheat bags in the godowns.

38. DAMAGE : The rice weevil is a serious pest in our country.
Both grubs and adults feed on rice grains, less commonly on wheat and maize grains.
Only the skin of the grains is left behind and the grains becomes incapable of germination and unfit for human consumption.

39. Nearly 50% of the damage in grain stores is due to this pest.
The maximum damage occurs from August to September.
The pest prefers humid climate and multiplies enormously in stores left undisturbed and uncared for.

40. CONTROL :
Control of weevils involves locating and removing all potentially infected food sources. Rice weevils in all stages of development can be killed by freezing infected food below -17.7 °C (0 °F) for a period of three days, or heating to 60 °C (140 °F) for a period of 15 minutes
Godowns should be sterilized by burning coke before storing grains.

41. Grains should be thoroughly dried and stored in clean, dry insect-proof stores.
Surface infestation can be checked by pyrethrum aerosol.
Fumigation of godowns containing grains with % Hydrocyanic acid gas for 18 hours or by carbon disulphide for 24 hours is very useful.

42. Wheat Weevil (Trogoderma granarium)

43. SYSTEMATIC POSITION
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Coleoptera Family: Dermestidae Genus: Trogoderma Species: T. granarium

44. DiSTRiBUTiON: The khapra beetle is native to Punjab, India.
It has also been discovered in North America.
It has become established in a number of Mediterranean, Middle Eastern, Asian and African countries. It has also been discovered in North America
Specially abundant in places having a temp 90 to 100°F

45. FEEdS ON : Feeds on wheat.
Occasionally attacks jowar, oat, rice and maize and rarely gram also.
Infest top layers of the stored material.

47. LiFE HiSTORY : Complete metamorphosis
Egg  Larva (Grub)  Pupa Adult.
Chewing type of mouthparts.

49. The female wheat weevil lays eggs, cylindrical with one end more rounded and the other more pointed, about 0.7 mm long and 0.25 mm broad, weighing about 0.02 mg singly among the grains.
Sometimes they are laid in groups of 2-3 glued to a grains.
The pointy end has a number of spine-like projections.
The eggs are initially a milky white, translucent, but over several hours turn a pale yellowish color.

51. Yellow white, 1.5mm. long, hairy grub emerge in 5 to 9 days under proper conditions of humidity and temperature.
They bore into the grains and feed on the content.
The female larvae become full-grown in 24 to 40 days and male in 20 to 30 days.
Mature larvae are up to 5 millimeters long and are covered in dense, reddish-brown hair with yellowish- brown transverse bands across the body.
The larvae moult 4 times during this period.

53. Pupation occurs in the last larval skin among the grains and takes 4 to 6 days.
The adult usually emerge in April or early may.
They pair 2 to 3 days after emergence, and the females start laying eggs in 1 to 3 days.
The female lives for 16 to 32 days after maturity, and lays 125 eggs during her life.
Breeding occurs in April to October and there are 4 to 5 broods in a year.

55. Larvae hibernate in winter in cracks and cervices of the walls and floor or in other sheltered places.
The beetle prefers hot, dry conditions and can be found in areas where grain and other potential food is stored, such as pantries, malthouses, grain and fodder processing plants, and stores of used grain sacks or crates.

56. GENERAL APPEARANCE :
The adult beetle oval, dark-brown, about 2 to 3 mm. long.
It has retractile head with clubbed antennae.
The entire body bears fine hair.
There is no demarcation between thorax and abdomen.
The males are smaller and darker than the females.

57. DAMAGE : The rice weevil is a major pest of wheat.
Occasionally attacks jowar, oat, rice and maize and rarely gram also.
Main damage is caused by the grubs.
Luckily, they infest only the top layers of the stored material, usually not going deeper than 50cm.
Maximum damage is caused from July to October.

58. CONTROL :
In case of attack, the upper infested portion of the grains may be carefully separated and suitably treated.
Adults and grubs can be trapped by spreading gunny bags over the infested grains. The pests being positively thigmotactic, cling to the bags whence they may be collected and killed.

59. Fumigation with methyl bromide is the most effective treatment
Fumigation with methyl bromide is the most effective treatment. Powdered neem has been used to control the beetle in wheat stores in India. Note that neem powder repels many insects with a strong odor, but generally does not kill them.

60. Rust Red Flour Beetle (Tribolium castaneum)

61. SYSTEMATIC POSITION
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Coleoptera Family: Tenebrionidae Genus: Tribolium Species: T. castaneum

62. DiSTRiBUTiON: Occur all over the world.
Most common pest of wheat flour.

63. FEEdS ON : Feeds on wheat grains.
Damage flour and flour products and grains damaged by other pests.
It also attacks dry fruits and prepared cereal foods such as cornflakes.

65. LiFE HiSTORY : Complete metamorphosis
Egg  Larva (Grub)  Pupa Adult.
Chewing type of mouthparts.

67. The rust-red flour beetle breeds from April to October.
The adults mate 1 or 2 days after emergence.
The female lays white, transparent, cylindrical, sticky eggs in the flour or the frassy material among the grains and other food stuffs.
Flour or dust adheres to them.
Worm like, yellowish-white, 1mm. long larvae emerge in 4 to 10 days, and become reddish yellow, hairy, 6mm. long full-grown larvae in 22 to 25 days after 6 or 7 moults.

69. Pupation occurs in the flour.
Yellowish, hairy pupa produces an adult in 6 to 9 days.
The entire life history is completed in 26 to 30 days in summer, winter is passed mostly in the adult stage.

71. The adult is long-lived, sometimes living more than three years.
GENERAL APPEARANCE :
The adult is long-lived, sometimes living more than three years.
The adult is about 3.5mm. long, reddish brown beetle with bent and clubbed antennae.
It is an active insect, capable of short flight, but generally remains concealed in flour.

72. DAMAGE :
Both the larvae and the adults cause damage to flour and flour products and also to the grains damaged by other pests.
The flour may turn greyish and mouldy with unpleasant smell, that makes it unfit for human consumption.

73. Lesser Grain Borer (Rhizopertha dominica)

74. SYSTEMATIC POSITION
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Coleoptera Family: Bostrichidae Genus: Rhyzopertha Species: R. dominica

75. DiSTRiBUTiON:
Originally inhabited India, but has now spread practically all over the world.
It is commonly called susri.

76. FEEdS ON : Feeds on cereals, pulses and millets.
They feed on flour formed by the boring beetles or they enter damaged grains and feed inside them.

78. LiFE HiSTORY : Complete metamorphosis Egg  Larva (Grub)Pupa  Adult.
Chewing type of mouthparts.

79. Rhizopertha dominica breeds from April to November, and passes winter hibernated as larva or adult.
The female lays about 0.67mm. long, glistening white eggs that are rounded at one end and pointed at the other.
They are deposited singly in the frass or glued to the grains in small groups.
The larvae emerge in 5 to 9 days.

81. They feed on flour formed by the boring beetles or they enter damaged grains and feed inside them.
They undergo 4 or 5 moults and become 5mm. long, full grown larvae in 25 to 50 days.
Pupation occurs within the grains for 4 to 7 days.
Adult cuts its way out of the grains.
There are 5 to 6 broods in a year.

83. GENERAL APPEARANCE :
The adult is a 3mm. long, shinning, dark- brown or black, cylindrical beetle.
The deflexed head is covered by a hood like pronotum and bears clubbed antennae.
The sexes are alike.
Polyandry and polygamy are common in this pest.
The adults can fly from one godown to another.

84. DAMAGE :
Both the larvae and the adults cause damage to the grains, reducing them to mere perforated shells.
They also produce a considerable frass on which the young grubs feed till they are able to bore into the grains.

85. Rice Moth (Corcyra caphalonica)

86. SYSTEMATIC POSITION
Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Lepidoptera Family: Pyralidae Subfamily: Galleriinae Tribe: Tirathabini Genus: Corcyra Species: C. cephalonica

87. DiSTRiBUTiON: Found in most countries.
Important stored grain pest of our country.

88. FEEdS ON : Feeds on rice and maize grains.
Also infest oil seeds and dry fruits.

90. LiFE HiSTORY : Complete metamorphosis
Egg  Larva (Caterpillar)  Pupa  Adult.
Siphoning type of mouthparts.

91. The Rice Moth (Corcyra cephalonica) is a pyraloid moth of the family Pyralidae. It is – as far as is known – the only living species of the genus Corcyra.
The rice moths are dark grey insects.
They breed in march to November.
Larvae hibernate in winter and pupates in spring.
The emerging moths are nocturnal and live for 2 to 4 days.
The female lays eggs singly or in small groups on the grains, bags or other objects in the godowns.

93. Creamy white larvae emerge in 4 to 7 days and feed under silken, weblike covers, preferring partially damaged grains.
Hey become full grown in 21 to 41 days after 5 moults.
They now prepare silken cocoon among the grains for pupation.
They change into adults in 9 to 14 days.
The entire life cycle takes about 33 to 52 days.
There about 6 generations in a year.

95. DAMAGE : The larvae damage the rice and maize grains.
With heavy infestation, entire stock of grains is changed into a webbed mass with foul smell.
The grains become unfit for human consumption
Also infest oil seeds and dry fruits.

96. General Control Of Stored Grains Pests:
The stores should be clean and well ventilated.
The stores should not be damp.
The grains to be stored should not have more than 10% of moisture in them. These may be dried by exposure to sun before storage.
One godown should be used to store only one kind of grain.
The floor, walls and ceilings of the godowns should not have holes, cracks and cervices to let the pests in.

97. If the stores are air-tight :-
Fumigate the empty store with HCN during April.
Fumigate the infested grain with either a mixture of ethylene dichloride and carbon tetrachloride, or methyl bromide.
If the stores are not airtight, spray the walls, floor and ceiling of the godown with 0.05% malathion emulsion and stack the bags on dunnage away from the walls.
Mix malathion 5% dust at the rate of 250gm with one quintal of grains meant for seed.
Disinfect old gunny bags by dipping them into % fenvalerate/cymbush in 10 litres of water for 10 minutes and dry them in shade before filing with grains. Better use new gunny bags each year.

98. CONTROL
Control measures include physical, chemical and biological measures.
PHYSICAL CONTROL:
Manipulation of the storage environment, making it less favourable for the insects.
Exposure of seeds to sun for 3 days in summer kill the pests.
Stores should be clean and well ventilated.
One godown should be used to store only one kind of grain.

100. 5. Cracks, holes and crevices in the walls ,floors and ceilings of the store house should be prevented for not letting the pests in.
CHEMICAL CONTROL:
Contact poisons and fumigants are used to kill the pests.
Pyrethrins of plant origins are mostly used due to low mammalian toxicity, unstable to sunlight, rapid breakdown.
Fenvalerate and Deltamethrin are synthetic pyrethroids, highly toxic to the larvae.

101. BIOLOGICAL CONTROL: This is a safe method to get rid of insect pests of stored grain.
Some of the biological species which are predators of the infecting pest are listed:
NATURAL ENEMY
TYPE
LIFE STAGES
1. Acaropsellina docta
Predator
Eggs/ Larvae
2. Amphibolous venator
Larvae
3. Antrocephalus mitys
Parasite
Larvae/ Pupae
4. Blattisocious keegani
5. Artema atlanta

103. THANKYOU