Storage Solutions to
Improve Food
Security for Small
Farmers
Floyd Dowell, Ph.D.
USDA ARS
Center for Grain and Animal
Health Research
Manhattan, Kansas
Post-Harvest Losses
• 10-33% of grain is lost to insects after harvest
in developing countries
Post-Harvest Losses
• 10-33% of grain is lost to insects after harvest
in developing countries.
• Most grain storage research addresses large
commercial storage structures, where losses
are usually very low.
Post-Harvest Losses
• 10-33% of grain is lost to
insects after harvest in
developing countries.
• Most grain storage research
addresses large commercial
storage structures where losses
are low.
• HOWEVER, many small
farmers store grain at home in
India and Africa, where losses
are much higher
Post-Harvest Losses
• 10-33% of grain is lost to
insects after harvest in
developing countries.
• Most grain storage research
addresses large commercial
storage structures.
• HOWEVER, many small
farmers store grain at home in
India and Africa.
• Most funding agencies
overlook on-farm storage
needs.
• But is there really anything wrong with a little
insect damage? Aren’t insects just “protein”?
Effect of Insect Damage on Grain
Quality
• Total protein increases as starch
decreases
• Thus insects are likely converting
starch to protein
• But . . . .
Protein Content
Starch Content
8.75
60.8
60.6
60.4
8.65
60.2
% Starch
% Protein
8.70
8.60
8.55
60.0
59.8
59.6
59.4
8.50
59.2
8.45
0
20
40
Days since infesting
60
80
59.0
0
20
40
Days since infesting
60
80
Effect of Insect Damage on Grain Quality
• Jood et al (Jaryana Ag. University)
showed that although Total PC
increase, the True PC decreases!
Total and True Protein Content
18
Protein Content, %
16
14
12
Total Protein
True Protein
10
8
6
0
10
20
30
40
50
Infestation Level, %
60
70
80
Effect of Insect Damage on Grain Quality
• Jood et al also showed that digestibility and
weight gain decrease significantly with infestation.
Protein Digestibility
Body Weight Gain
75
16
70
Digestibility, %
Weight Gain, g
14
12
10
8
65
60
55
50
45
6
40
4
0
10
20
30
40
50
Infestation Level, %
60
70
80
0
20
40
Infestation Level, %
60
80
Effect of Insect Damage on Grain Quality
• Besides a loss in nutrients,
there is an obvious loss in grain
weight.
Grain Weight Loss
1.005
Normalized Sample Weight
1
0.995
Control
0.99
Lesser Grain Borer
0.985
Rice Weevil
0.98
0.975
0
10
20
30
40
Days Since Infesting
50
60
Increase in Insects Over Time in Stored Grain
9000
Number of insects per kg
8000
7000
6000
5000
4000
3000
2000
1000
0
0
10
20
30
40
50
60
Storage Period, days
70
80
90
100
Current Types of Insect Control
 Chemical dusts (Actellic Super, Actellic Golden
Dust, Shumba Super, Stocal Super, Spinosad)
 Chemical gas (Phostoxin, Methyl Bromide)
 Diatomacious earths (Protect-It, PyriSec, and
DEA-P, Dryacide )
 Oxygen-free storage using
bags such as those provided
by GrainPro, or triple bagging
promoted in West Africa.
Problems with some available methods:
• Counterfeits!
Problems with some available methods:
• Rodents and insects chewing through
commercial oxygen-free bags.
Rats!
What Alternatives are Available for Small Farmers
with Few Resources?
 Treated bednets
 Repellents
 Controlled atmosphere
What Alternatives are Available for Small Farmers
with Few Resources?
 Treated bednets
Appropriate Alternatives to Control Insects
- Insecticide Treated Seed Bags • Similar technology as used in insecticide-treated bednets for
malaria control.
• After 3 weeks, there were no live insects in treated bags.
• Untreated bags had significant damage.
Control (left) and Treated Bag (right)
Appropriate Alternatives to Control Insects
- Insecticide Treated Seed Bags • Vestergaard-Frandsen is working on a treated seed
bag appropriate for developing countries.
• May possibly provide stored grain pest and
mosquito control with one bag?
Potential Test Site
What Alternatives are Available for Small Farmers
with Few Resources?
 Treated bednets
 Repellents
Appropriate Alternatives to Control Insects
- Food-Safe Repellent • Same technology as used for repelling flies,
mosquitoes, and other disease vectors.
• No insect damage at a 1% w/w application rate.
Test Cage
Appropriate Alternatives to Control Insects
- Food-Safe Repellent • We are working with the CDC and Stratacor to
field test this repellent in grain in Kenya.
What Alternatives are Available for Small Farmers
with Few Resources?
 Treated bednets
 Repellents
 Controlled atmosphere
Appropriate Alternatives to Control Insects
- Controlled Atmosphere Storage • Composting material can be used to produce
carbon dioxide that can then be used to control
insects in storage.
CO2
CO2
Appropriate Technologies to
Control Insects
- Controlled Atmosphere Storage • Composting material can be used to produce
carbon dioxide that can then be used to control
insects in storage.
Controlled Atmosphere Storage
Extracted CO2 from
Composting Material
Appropriate Alternatives to Control Insects
- Controlled Atmosphere Storage -
Insect Damaged Kernels vs CO2 Content
30
30
25
25
No. Damaged Kernels
No. Damaged Kernels
Insect Damaged Kernels vs O2 Content
20
15
10
5
0
20
15
10
5
0
3.7
3.8
4
O2 Content, %
7.1
19.4
1.3
15.3
15.5
CO2 Content, %
16
28.7
Appropriate Alternatives to Control Insects
- Controlled Atmosphere Storage • We showed that as oxygen content decreases
and carbon dioxide content increases, damage
by insects decreases.
Oxygen
Carbon Dioxide
35
O2 or CO2 Content
30
25
20
15
10
5
0
0
5
10
15
20
Number of Damaged Kernels, %
25
30
Appropriate Alternatives to Control Insects
In summary, the following low-cost solutions may soon be
available to help improve food security for small farmers.
• Treated seed bags
• Repellents
• Controlled atmosphere storage
All have a very low cost