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, paul.fields@agr.gc.ca2 Canadian Grain Commission, 3 University of Manitoba.

Overview

• Storage Structures• Insects in Stored Grain• Prevention• Detection• Control

Farm Storage

Moisture Migration

Temporary Farm Storage

• 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

Silobags Costs

• Extracter + bagger = $80,000• Bag = $2/tonne ($0.06/bu)• Bags 60 m long, store about 200 t (7000

bu) wheat

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

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

Loading with Canola with Bagger

Loading Canola into Bag

Finishing off Bag

Sealing Bag

Rolling Membrane to Seal Bag

Starting New Bag

Unloading with Extractor

Extractor

Cleaning up Front End Loader

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

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

Delivery to Elevator

Terminal Elevator

Overview

• Storage Structures• Insects in Stored Grain• Prevention• Detection• Control

Canadian Grain Act

• Illegal to sell, transport grain that is infested.

• Insect-free grain helps guarantee high quality of Canadian grain.

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

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

Rusty Grain Beetle

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

Insects Pests of Grain Rare/Localized

Sawtoothed grain beetleOryzaephilus surinamensis

Mites

old.

padi

l.gov

.au

Psocids

Rice or Granary WeevilsSitophilus oryzaeSitophilus granarius

Overview

• Storage Structures• Insects in Stored Grain• Prevention

– Clean Grain into Clean Silos– Dry grain– Cool grain

• Detection• Control

Sanitation• Clean up food residues• Treat empty bins with insecticide

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

Overview

• Storage Structures• Insects in Stored Grain• Prevention• Detection• Control

Detection of Insects in Grain

• You stumble upon them

Detection of Insects in Grain

• You look for them (Berlese funnels)

Detection of Insects in Grain

Probe pitfall trapsCone pitfall traps

• You ask them to help (traps)

Electronic grain probe

Opisystems, Calgary AB1-800-661-1055

Insector: Electronic trap

Carbon dioxide measuring to detect insects or moulds

Pests of Stored Grain

• Storage Environment• Pests • Detection• Control Methods

– Extreme temperatures– Fumigants– Contact insecticides– Biological control– Physical control

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

Cold

• Turning grain• Aeration of grain• Rusty grain beetle• -5oC for 8 weeks • -10oC for 6 weeks • -15oC for 4 weeks

Overview

• Insects in Stored Grain• Prevention• Detection• Control

– Extreme temperatures– Fumigants– Contact insecticides– Biological control– Physical control

Grain Fumigants

• Phosphine: PH3

• Carbon dioxide: CO2

• Sulfuryl fluoride: SO2 F2 (under review)• Methyl bromide: CH3 Br (being phased out)

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

Aluminum phosphide

Phostoxin® tablet prepac33 g of phosphine

Phostoxin® tablets1 g of phosphine

Phostoxin® pellets0.2 g of phosphine

Aluminium Phosphide ReactionAlP + 3 H2 O →

Al(OH)3 + PH3

solid liquid solid gas

Al(OH)3

• Precise control of dosage

• Uniform distribution of pellets

• Workers don’t enter bin

• Done during grain loading

Automatic Distributor

• 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

Gaseous Phosphine: ECO2 FUME

• 2% phosphine in 98% CO2 in cylinder• Quicker, accurate dosing• Faster than MgPH3 packs

Phosphine Resistance

• Extensive phosphine resistance in Oklahoma USA, Australia, India, Brazil

• Renders phosphine fumigations ineffective

• Populations 30-500 fold more resistance to phosphine

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

High pressure CO2 fumigation

• High value products• Spices and pet food in Europe• Quick & expensive

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

Overview

• Insects in Stored Grain• Prevention• Detection• Control

– Extreme temperatures– Fumigants– Contact insecticides– Biological control– Physical control

Treating Grain with Insecticides

• Malathion– Wide spread resistance

• Diatomaceous Earth– Grain must below 14% mc– Lowers test weight– Long lasting

Take Home Message: Residual Insecticides

• Advantages– Long term protection– Inexpensive

• Disadvantages– Consumers concerned about insecticides– Worker exposure to insecticides– Resistance to insecticides– Kills parasites

Overview

• Insects in Stored Grain• Prevention• Detection• Control

– Extreme temperatures– Fumigants– Contact insecticides– Biological control– Physical control

Future Solutions for Warehouses

• Parasitoids• Trichogramma• Bracon hebator• In USA in grain• In Germany inhealth food stores

Overview

• Insects in Stored Grain• Prevention• Detection• Control

– Extreme temperatures– Fumigants– Contact insecticides– Biological control– Physical control

Unloading Grain

Pneumatic auger

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

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

Acknowledgments

Degesch America (phosphine slides)Dr. Zlatko Korunic (contact insecticide slides)Canola Council (Funding Silobag study)