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Issues in Grain Storage: How to Avoid Surprises at Delivery
Paul Fields1
Noel White1, Blaine Timlick2, Fuji Jian3 and Digvir Jayas3
1 Agriculture and Agri-Food Canada, Cereal Research Centre, [email protected] Canadian Grain Commission, 3 University of Manitoba.
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Overview
• Storage Structures• Insects in Stored Grain• Prevention• Detection• Control
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Moisture Migration
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Temporary Farm Storage
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• Silobags, grain bags, grain harvest bags• Used in Australia and South America,
Canada• Started in Argentina in 1995• Argentina in 2006 stored 20 million tonnes
Temporary Farm Storage
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Silobags Costs
• Extracter + bagger = $80,000• Bag = $2/tonne ($0.06/bu)• Bags 60 m long, store about 200 t (7000
bu) wheat
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Silobags
• Low cost storage• Lower transportation costs• Flexible storage• Segregation of crops• Place in well drained ground• Crest of hill• Away from woods (deer)• Deer, birds, rodents can puncture bag• Fences/netting to reduce animal damage• Few options for management once in bag
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Silobags
• Manufacturers claim that bags are airtight• Australian study shows wide variation in
airtightness (Darby and Caddick 2007)• Only 2/13 bags of bags on farms airtight• Some bags initially very airtight, but after
several months some lost airtightness• Careful loading and regular repair needed
to maintain airtight seal
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Loading with Canola with Bagger
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Loading Canola into Bag
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Finishing off Bag
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Rolling Membrane to Seal Bag
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Unloading with Extractor
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Cleaning up Front End Loader
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Bag Storage of Canola, Winnipeg
• 20 t canola at 8,10 and 14% mc• Sampled for quality, temperature and CO2
• Stored from Oct 2010-Aug 2011• 14% canola extensive spoilage
– Recommend only storage for few months• 8 and 10% mc no significant quality loss
– Recommend only storage for 10 months
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Argentina Silobag Guidelines
Cereals(mc %)
Oilseed(mc %)
Months in StorageLow Risk
Medium Risk
High Risk
Below 14 Below 11 6 12 24
14-16 11-14 2 4 6
Above 16 Above 14 1 2 4
Darby and Caddick 2007
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Delivery to Elevator
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Terminal Elevator
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Overview
• Storage Structures• Insects in Stored Grain• Prevention• Detection• Control
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Canadian Grain Act
• Illegal to sell, transport grain that is infested.
• Insect-free grain helps guarantee high quality of Canadian grain.
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Month0 1 2 3 4 5 6 7
Num
ber o
f Ins
ects
(100
0x)
0
20
40
60
80
100
Khapra beetle 12x/mGranary weevil 15x/mRed flour beetle 60x/m
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Rusty Grain Beetle Cryptolestes ferrugineus• Food: broken grain, germ, mould• Egg to Adult: 3 wks• Adult Longevity: 10-30 wks• Eggs/female: 400• Rate of increase: 60 fold/month• Size: 1.6-2.2 mm
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Rusty Grain Beetle
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Flour Beetles
• Food: broken grain, mould, germ• Egg to Adult: 3- 8 wks• Adult Longevity: 45 - 70 wks• Eggs/female: 450 • Rate of increase: 60-70 fold/month• Size: 3-4 mm
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Insects Pests of Grain Rare/Localized
Sawtoothed grain beetleOryzaephilus surinamensis
Mites
old.
padi
l.gov
.au
Psocids
Rice or Granary WeevilsSitophilus oryzaeSitophilus granarius
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Overview
• Storage Structures• Insects in Stored Grain• Prevention
– Clean Grain into Clean Silos– Dry grain– Cool grain
• Detection• Control
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Sanitation• Clean up food residues• Treat empty bins with insecticide
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Insecticide Treatment of Empty Bins
• Malathion– Extensive resistance– Do NOT treat canola bins
• Cyfluthrin (Tempo)• Diazon• Dichlorvos• Pyrethrum with PBO• Diatomaceous Earth
– Needs dry conditions
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Overview
• Storage Structures• Insects in Stored Grain• Prevention• Detection• Control
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Detection of Insects in Grain
• You stumble upon them
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Detection of Insects in Grain
• You look for them (Berlese funnels)
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Detection of Insects in Grain
Probe pitfall trapsCone pitfall traps
• You ask them to help (traps)
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Electronic grain probe
Opisystems, Calgary AB1-800-661-1055
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Insector: Electronic trap
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Carbon dioxide measuring to detect insects or moulds
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Pests of Stored Grain
• Storage Environment• Pests • Detection• Control Methods
– Extreme temperatures– Fumigants– Contact insecticides– Biological control– Physical control
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Temperature Effects on InsectsTe
mpe
rat u
re(°
C)
Tem
pera
ture
(°F)
-30
-20
-10
0
10
20
30
40
50
60
70
-20
0
20
40
60
80
100
120
140
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Cold
• Turning grain• Aeration of grain• Rusty grain beetle• -5oC for 8 weeks • -10oC for 6 weeks • -15oC for 4 weeks
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Overview
• Insects in Stored Grain• Prevention• Detection• Control
– Extreme temperatures– Fumigants– Contact insecticides– Biological control– Physical control
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Grain Fumigants
• Phosphine: PH3
• Carbon dioxide: CO2
• Sulfuryl fluoride: SO2 F2 (under review)• Methyl bromide: CH3 Br (being phased out)
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Phosphine Fumigation: AlPH3 / PH3• Most common chemical control• 5oC grain temp. limit• Restricted use
The use and sale of aluminum phosphide is restricted to licensed pesticide applicators possessing a stored agricultural products license
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Aluminum phosphide
Phostoxin® tablet prepac33 g of phosphine
Phostoxin® tablets1 g of phosphine
Phostoxin® pellets0.2 g of phosphine
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Aluminium Phosphide ReactionAlP + 3 H2 O →
Al(OH)3 + PH3
solid liquid solid gas
Al(OH)3
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• Precise control of dosage
• Uniform distribution of pellets
• Workers don’t enter bin
• Done during grain loading
Automatic Distributor
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• Equal distribution of gas
• Workers stay outside bin
• No movement of grain
• Permanent or temporary installation
• Dosage can be reduced
• For silos 20 m or higher
Recirculation Method
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Gaseous Phosphine: ECO2 FUME
• 2% phosphine in 98% CO2 in cylinder• Quicker, accurate dosing• Faster than MgPH3 packs
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Phosphine Resistance
• Extensive phosphine resistance in Oklahoma USA, Australia, India, Brazil
• Renders phosphine fumigations ineffective
• Populations 30-500 fold more resistance to phosphine
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Carbon Dioxide
• Needs warmer temperatures than PH3
• Needs longer durations than PH3
• 80% CO2 for 9 d• 60% CO2 for 11 d• 40% CO2 for 17 d• 20% CO2 weeks to months • 70% to not less than 35% at 15 d
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High pressure CO2 fumigation
• High value products• Spices and pet food in Europe• Quick & expensive
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Take Home Message: Fumigants
• Advantages– Quick– Kills internal stages– Minimal residual chemicals in grain
• Disadvantages– All fumigants very, very toxic– Need grain above 5oC– No residual effect– Some resistance to phosphine: Australia,
Brazil, India, USA
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Overview
• Insects in Stored Grain• Prevention• Detection• Control
– Extreme temperatures– Fumigants– Contact insecticides– Biological control– Physical control
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Treating Grain with Insecticides
• Malathion– Wide spread resistance
• Diatomaceous Earth– Grain must below 14% mc– Lowers test weight– Long lasting
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Take Home Message: Residual Insecticides
• Advantages– Long term protection– Inexpensive
• Disadvantages– Consumers concerned about insecticides– Worker exposure to insecticides– Resistance to insecticides– Kills parasites
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Overview
• Insects in Stored Grain• Prevention• Detection• Control
– Extreme temperatures– Fumigants– Contact insecticides– Biological control– Physical control
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Future Solutions for Warehouses
• Parasitoids• Trichogramma• Bracon hebator• In USA in grain• In Germany inhealth food stores
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Overview
• Insects in Stored Grain• Prevention• Detection• Control
– Extreme temperatures– Fumigants– Contact insecticides– Biological control– Physical control
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Impact machine
• Pin mills, Entoleters• Kill insects by impact• 2,500 g• Flour, semolina, grain• Can lower mill capacity• Cost of power• Higher speeds = higher mortality• Lower throughput = higher mortality
www.entoleter.com
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Websites• Canadian Grain Commission Grain Storage,
Winnipeg, Canada• USDA ARS Stored Product Insect Research
Unit, Manhattan, KS, USA• Stored Product Protection Electronic book on
grain storage• Subramanyam Bhadriraju's Lab, Dept. Grain
Science and Industry, KSU, Manhattan, KS, USA
• Western Australia Grain Storage Publications• Purdue University
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Acknowledgments
Degesch America (phosphine slides)Dr. Zlatko Korunic (contact insecticide slides)Canola Council (Funding Silobag study)