Storage Pests and its Management
Storage pests causes different kinds of losses viz.
⮚ Quantitative loss
⮚ Qualitative loss
⮚ Loss of seed viability
Storage insect pests are categorized into two types viz.
⮚ Primary storage pests: Pests that cause enormous loss and mainly responsible for most of the damage to
grain in farm, transportation and storage. Eg: Sitophilus oryzae, Sitotroga cerealella.
They are classified as Internal feeders and External feeders
⮚ Secondary storage pests: Those pests which are frequently associated with particular environmental
conditions such as high and low moisture or temperature and poor sanitation. Eg.Oryzaephilus
surinamensis, Cryptolestis ferrugineus, Stegobium paniceum.
Primary storage pests: Insects that damages sound grains are primary storage pests
Common name Pest Family Order
Internal Feeders
Rice weevil Sitophilus oryzae, Curculionidae Coleoptera
S. zeamais, S. granarius
Lesser grain borer Rhyzopertha dominica Bostrychidae Coleoptera
Angoumois grain moth Sitotroga cerealella Gelechiidae Lepidoptera
Pulse beetle Callosobruchus chinensis, Bruchidae Coleoptera
C. maculatus
Potato tuber moth Phthorimoea operculella Gelechiidae Lepidoptera
Cigarette beetle Lasioderma sericorne Anobiidae Coleoptera
Sweet Potato weevil Cylas formicarius Apionidae Coleoptera
Tamarind Beetle Pachymeres gonagra Bruchidae Coleoptera
Drug store beetle Stegobium paniceum Anobiidae Coleoptera
Arecanut beetle Araecerus fasciculatus Anthribidae Coleoptera
External Feeders
Red flour beetle Tribolium castaneum, Tenebrionidae Coleoptera
Tribolium confusum
Indian meal moth Plodia interpunctella Phycitidae Lepidoptera
Fig moth or almond Ephestia cautella Phycitidae Lepidoptera
moth
Rice moth Corcyra cephalonica Galleriidae Lepidoptera
Khapra beetle Trogoderma granarium Dermestidae Coleoptera
Secondary storage pest: Insects that damage broken or already damaged grains secondary storage pests.
Common name Pest Family Order
Saw toothed grain beetle Oryzaephillis Silvanidae Coleoptera
surinamensis
Flat grain beetle Cryptolestus minutas Cucujidae Coleoptera
Long headed flour beetle Latheticus oryzae Tenebrionidae Coleoptera
Grain mite Acarus siro Acaridae Acari
1.Rice weevil: Sitophilus oryzae, S. zeamais, S. granaries
F: Curculionidae O: Coleoptera
Host range: Wheat, rice, maize, jowar, paddy
Symptoms of damage: Both grub and adults cause damage. Grains are hollowed out and the kernels are reduced
to powdered form. S. oryzae and S. zeamais starts its attacking in field itself. Adults cut circular holes on grains.
2.Khapra beetle/Cabinet beetle: Trogoderma granarium
F: Dermestidae O: Coleoptera
Host range: Wheat, maize, jowar, rice, pulses, oil seeds
Symptoms of damage: Grub damages the grain starting with germ portion, scratching the grain surface and
devouring the grain. The larva is the most destructive life stage, as the adults only live for 2–3 weeks with no or
limited feeding. It reduces the grain into frass. Crowding of larvae leads to unhygienic conditions in warehouses.
3.Lesser grain borer/Hooded grain borer/paddy borer beetle: Rhyzopertha dominica
F: Bostrichidae O: Coleoptera
Host range: Paddy, rice, wheat, maize.
Symptoms of damage: Grubs and adults cause damage and are voracious feeders. Adults reduce the grain
kernels to frass. Grubs eat their way into the grain or feed on the grain dust and are capable of attacking grain
externally.
4. Rust red flour beetle: Tribolium castaneum and Confused flour beetle: Tribolium confusum
F: Tenebrionidae O: Coleoptera
Host range: Broken grains/ mechanically damaged grains, germ portion and milled products.
Symptoms of damage: Grubs feed on milled products. Flour beetles are secondary pests of whole grains and
primary pests of flour and other milled products. In grains, embryo or germ portion is 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
5. Pulse beetle: Callosobruchus chinensis, C.analis
F: Bruchidae O: Coleoptera
Symptoms of damage: Grubs eat up the grain kernel and make a cavity. Adults come out making exit holes
6.Saw toothed grain beetle: Oryzaephilus surinamensis
F: Silvanidae O: Coleoptera
Symptoms of damage: Adults and larvae causes roughening of grain surface producing off odour.
INTEGRATED MANAGEMENT OF STORED PRODUCE PESTS
The control measures for stored produce pests can be classified into preventive and curative measures.
Preventive measures
Remove all debris in the godown.
Clean and maintain the threshing floor/yard free from insect infection.
Clean the machines like harvester and thresher before their use.
Periodic cleaning of godowns/ storage structures before and after storing the harvested crop
Provide a metal sheet upto a height of 25 cm at the bottom of the wood in doors to arrest the entry of rats.
Fix up wire meshes to windows, ventilators, gutters, drains etc., to prevent entry of rats, birds and squirrels.
Remove and destroy dirt, rubbish, sweepings and webbings etc from the stores.
• Close all the rat burrows found in godown with a mixture of broken glass pieces and mud plastered with mud/
cement.
• Plaster the cracks, crevices, holes found on walls, and floors with mud or cement and white wash the stores
before storing of grains.
• Provide dunnage leaving gangway or alleyway of 0.75 to 1 m all around to maintain good storage condition.
• Disinfest the storage structures receptacles by spraying malathion 50 EC @ 3 lit 100 m before their use.
Curative measures
i) Ecological methods
• Manipulate the ecological factors like temperature, moisture content and oxygen through design and construction
of storage structures/ godown and storage to create ecological conditions unfavourable for attack by insects.
• Temperature above 42℃ and below 15℃ retards reproduction and development of insect while prolonged
temperature above 45℃ and below 10℃ may kill the insects.
• Dry the produce to have moisture content below 10% to prevent the build-up of pests.
• Kill the pest’s bio stages harbored in the storage bags, bins etc., by drying in the sun light.
• Store the grains at around 10 % moisture content to escape from the insect’s attack.
• Manipulate and reduce oxygen level by 1% to increase the CO 2 level automatically, which will be lethal to all
the stages of insects.
ii) Physical methods
• Provide a super heating system by infrared heaters in the floor mills and food processing plants to obtain effective
control of pests since mostly the stored produce insects die at 55 –60℃ in 10 – 20 minutes.
• Modify the storage atmosphere to generate low oxygen (2.4% and to develop high carbon dioxide (9.0 – 9.5) by
adding CO2 to control the insects.
• Seed purpose: Mix 1 kg of activated kaolin (or) lindane 1.3 D (or) malathion 5 D for every 100 kg of seed and
store/pack in gunny or polythene lined bags.
• Grain purpose: Mix 1 kg activated kaolin for every 100 kg of grain and store. To protect the pulse grains, mix
activated kaolin at the above dosage or any one of the edible oils at 1 kg for every 100 kg of grain or mix 1 kg of
neem seed kernel for every 100 kg of cereal / pulse and store.
• Do not mix synthetic insecticides with grains meant for consumption.
iii) Cultural methods
• Split and store pulses to escape from the attack by pulse beetle since it prefers to attack whole pulses and not
split ones.
• Store the food grains in air tight sealed structures to prevent the infestation by insects.
iv) Mechanical methods
• Sieve and remove all broken grains to eliminate the condition which favour storage pests.
• Stitch all torn out bags before filling the grains.
v) Chemical methods
• Treat the walls, dunnage materials and ceilings of empty godown with malathion 50 EC 10 ml/L (or) DDVP 76
WSC 7 ml/L1 at 3 L spray solution/10 sq.m.
• Treat the alleyways and gangways with malathion 50 EC 10 ml/L or DDVP 76 WSC 7 ml/ L (1 L of spray
fluid/270 m3).
• Spray malathion 50 EC 10 ml/ L with @ 3 L of spray fluid / 100 m2 over the bags.
• Do not spray the insecticides directly on food grains.
• Use knock down chemicals like lindane smoke generator or fumigant strips pyrethrum spray to kill the flying
insects and insects on surfaces, cracks and crevices.
• Use seed protectants like pyrethrum dust, carbaryl dust to mix with grains meant for seed purposes only.
• Decide the need for shed fumigation based on the intensity of infestation.
• Check the black polythene sheets or rubberized aluminium covers for holes and get them ready for fumigation.
• Use EDB ampoules (available in different sizes 3 ml, 6 ml, 10 ml, 15 ml and 30 ml) at 3 ml/quintal for wheat
and pulses and 5 ml/ quintal for rice and paddy (Do not recommend EDB for fumigation of flour oil seeds and
moist grains)
• Use EDCT (available in tin containers of 500 ml, 1 liter and 5 litres) at 30 – 40 litres/ 100 cubic meter in large
scale storage and 55 ml/quintal in small scale storage.
FUMIGATION
Use fumigants like ethylene dibromide (EDB), ethylene dichloride carbon tetra chloride (EDCT), aluminium
phosphide (ALP) to control stored produce pests effectively. Apply aluminum phosphide (available in 0.6 g and
3 gram tablets) @ 3 tablets (3 grams each) per tonne of food grains lot with help of an applicator. Choose the
fumigant and work out the requirement based on the following guidelines.
• 3 tablets of aluminum phosphide 3 g each per tonne of grain.
• 21 tablets of aluminium phosphide 3 g each for 28 cubic meters
• Period of fumigation is 5 days
Mix clay or red earth with water and make it into a paste form and keep it ready for plastering all-round
the fumigation cover or keep ready sand snakes. Place the required number of aluminium phosphide tablets in
between the bags in different layer. Cover the bags immediately with fumigation cover. Plaster the edges of cover
all round with wet red earth or clay plaster or weigh down with sand snakes to make leaf proof. Keep the bags for
a period of 5-7 days under fumigation based on fumigant chosen. Remove the mud plaster after specified
fumigation periods and lift cover in the corner to allow the residual gas to escape. Lift the cover after few hours
to allow aeration.
