Pest management in storage
Joe Rickman and Martin Gummert,
Agricultural Engineering,
International Rice Research Institute, Philippines
Pest of stored grains
•
•
•
•
Insects
Pathogens (fungi)
Rodents
Birds
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Ideal Conditions for pest
Environment Conditions
• Temperature 20 - 40oC
• Relative humidity 60-70%
Mixing grain lots
• old and new
Time
• Longer storage >no insects
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Common Post harvest insects
• Lesser
grain
borer
(Rhzopertha dominica),
• Rice weevil (Sitophilus
oryzae),
• Angoumois grain moth
(Sitotroga cerealella),
• Red
flour
beetle
(Tribolium castaneum)
Lifecycle
• Beetles 15-18 days
• Moths 28 - 35 days
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Management of insect pests
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Harvesting and drying
• Grain moisture
content (12-14%)
• Minimize cracked
and broken grain
during processing
• Don’t mix old and
new grain
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Cleaning and disinfesting the
storage system
• Clean storage - containers, structures, equipment
and bags
• May need to treat with insecticide
– Malathion (50EC) at 5ml/20l of water @20ml/m2,
– Fenitrothion (50EC) at 5ml/l water @20ml/m2,
– Deltamethrin
(2.5%
WP)
at
1.5g/l
@20ml/m2
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water
Treat infected grain
Grain treatment
• Insecticide- malathion
• Fumigation
– phosphine,
– carbon dioxide
Physical
• Heat < 15, >55 (15mins)
• Impact
– pneumatic conveyers
• Diatomaceous earth
– dehydration
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Sealing the system
(low oxygen system)
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Live Insect Counts
(Insects/ kg)
Months
Open
Storage
Hermetic
(5 ton)
Hermetic
(small)
Cold
room
Air
conditioner
(bags)
0
3.2
8.8
7.4
8.4
8.4
3
234
0
1.4
0
1.6
6
114
0.4
1.6
0
3.0
9
54.4
0.4
1.2
0
3.4
12
27.2
2.2
1.2
0
9.0
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Bag dipping
(Live Insects/kg)
Days
Control
Deltamethrin
(bag dipped)
Phosphine
Tablet
0
10
10
7.6
25
30
5
0
53
72
1
0
98
86
1
3.6
125
48
0
11
159
6
0
28.6
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Rats
Species
• Black rat or House rat (Rattus rattus)
• Norway rat or Common rat (Rattus norvegicus)
• House mouse (Mus musculus)
Damage
• Feed on grain
– rats 25 gm of food per day,
– mice 3-4 gm per day
• Spoilage and contamination of grain
• Damage materials –tarpaulins, bags, electric cables
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Rat management
• Keep the store clean-remove any spilt grain
• Store bags in tidy stacks set up on pallets,
• Store any empty or old bags and fumigation sheets
on pallets, and if possible in separate stores!
• Keep the store free of rubbish Bum or bury it!
• Keep the area surrounding the store free of tall
weeds
• Keep the area in the vicinity of the store free of any
stagnant water
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Fungi
Most common :
• Aspergillus and Penicillium
• Grain spoilage and mycotoxins (poisonous)
Determined by:
• Moisture content of the stored grain
• Temperature
• Condition of the grain going into storage
• Length of time the is grain stored and
• Amount of insect and mite activity in the grain.
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Fungi
Control
• Moisture content (12-14%)
• Heat
– dry heat at 65oC for 6 days
– hot water treatment at 52-55oC
• Fungicides
– Dithane M-45 and Benlate at 3 grams kg-1.
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Storage Hygiene
• Keep storage areas clean.
• Clean storage rooms after they are emptied
• Placing rat-traps and barriers in drying and storage
areas. Cats deter and help control rats and mice
• Inspect storage room regularly to keep it vermin
proof.
• Inspect the stored seeds once a week for signs of
insect infestation.
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Priorities Management Options
1. Good hygiene -cleanliness
in store, clean bags
2. Hermetic storage
3. Bag dipping
4. Phosphine tablets
5. Fumigation-last resort
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