1. Kerstin Hell, Kukom Edoh Ognakossan and Ousmane Coulibaly
LOGO IITA
Purdue Improved Cowpea Storage (PICS) – Potential for Application in West Africa?
Kerstin Hell, Kukom Edoh Ognakossan and Ousmane Coulibaly

2. Traditional storage system
Environmental conditions, traditional farming methods, improper grain drying and storage practices facilitate quality reduction and insect infestation in African Post-harvest systems
Grain losses due to Insects in West-Africa
>30% in maize stores infested with Prostephanus truncatus
10-12 % in maize infested with Sitophilus zeamais
Several African staple commodities are affected by high losses due to insects – maize, millet, groundnut, rice, sorghum and processed yam and cassava products
Post-harvest Loss Network determined losses for cereals of 17.4% to 14.3% (2003 till 2008)
Traditional storage systems have high losses

3. Hermetic storage trials at IITA-Benin
Testing of IRRI Superbags (‘09) and PICS-Bags (‘09) for control of P. truncatus & S. zeamais on maize
Testing of PICS Bags for control of insects in maize (’10 & ’12) and cassava chips (’11 & ‘12)
Destructive sampling
Moisture content, insect species, grain losses, holes on bags, CO2 and O2 levels
Cost/benefit analysis to determine financial profitability
PICS bag

4. Mortality rate (%) of insects in IRRI Super bag (ISB) on maize
Days after storage
S. zeamais
P. truncatus
Mixture (S. zeamais + P. truncatus)
ISB
Control
Infestation with 10 insects 60
96.30 ± 3.70 Aa
5.28 ± 0.19 Ab
83.45 ± 8.31 Aa
7.74 ± 1.14 Ab
92.05 ± 1.45 Aa
7.90 ± 1.98 Ab 90
98.04 ± 1.96 Aa
7.94 ± 2.98 Ab
92.70 ± 7.29 Aa
10.80 ± 2.38 ABb
87.80 ± 6.76 Aa
9.06 ± 2.04 Ab
120
100 Aa
10.38 ± 1.24 Ab
85.06 ± 5.24 Aa
24.29 ± 5.76 Bb
92.63 ± 7.36 Aa
19.82 ± 1.86 Bb
150
10.64 ± 3.05 Ab
25.51 ± 5.43 Bb
24.13 ± 2.15 Bb
Infestation with 25 insects
92.48 ± 6.02 Aa
7.59 ± 0.84 Ab
99.52 ± 0.47 Aa
7.77 ± 0.66 Ab
92.75 ± 4.46 Aa
9.70 ± 1.42 Ab
10.93 ± 0.13 Bb
87.97 ± 6.03 Aa
10.51 ± 1.47 Ab
50.08 ± 7.78 Ba
16.32 ± 1.26 Bb
14.01 ± 0.99 Cb
73.04 ± Aa
19.41 ± 1.82 Bb
90.81 ± 9.18 Aa
22.27 ± 2.00 Bb
17.74 ± 1.16 Db
82.92 ± Aa
21.83 ± 1.57 Bb -
Mean (± SE) within a column (row) followed by the same uppercase letter (lowercase) are not significantly different from each other at 5% probability level

5. Mortality rate (%) of insects in IRRI Super bag and PICS on maize
Mortality rate (Mean % ± SE)a
Treatments
P. truncatus
S. zeamais
3 months of storage
6 months of storage
IRRI
100 ± 0.00Aa
90.97 ± 4.40 Ab
PICS
95.83 ± 4.16Aa
PPB (Control)
96.43 ± 2.33Aa
11.35 ± 1.71Bb
34.05 ± 2.69Ba
Mean (± SE) within a column (row) followed by the same uppercase letter (lowercase) are not significantly different from each other at 5% probability level

6. Means numbers of holes on PICS Bag and PPB
PsB
PPB

7. Effect of PICS & IRRI Bag on maize post-harvest pest after 3- and 6-month
Number of adult insects per kg of maize grains (Mean ± SE)a
P. truncatus
S. zeamais
C. quadricolis
Tribolium spp.
Treatments
3 months of storage
6 months of storage
IRRI
0.62
± 0.24 Aa
0.47
± 0.23 Aa
1.95
± 0.47 Aa
1.52
± 0.34 Aa
0.00
± 0.00 Aa
PICS
0.75
± 0.38 Aa
0.30
± 0.11 Aa
2.47
± 0.69 Aa
1.35
± 0.41 Aa
PPB (Control)
±0.27 Aa
0.96
± 0.12 Ba
234.37
± Ba
238.75
± 2.38 Ba
147.05
± 7.82 Ba
355.05
± Bb
44.77
± 5.18 Ba
191.65
± 6.83 Bb
Pest densities were significantly reduced in hermetic bags compared to control polypropylene Bags (PPB) (P=0.018)
In control bag insect densities increased significantly with storage time (P < )
In hermetic storage, P. truncatus was found ONLY when maize was artificially infested whereas in the control it all bags had this species

8. Effects of PICS & IRRI Bags on maize grain losses after 3- and 6-months
Losses were significantly lower in PICS & IRRI-bags .
No increase of losses in PICS & IRRI with storage.
In polypropylene bags losses increased with storage time reaching nearly 18%.

9. Financial benefits of PICS
Maize prices in three local markets
Maize prices in three local markets
Benefit Cost Ratio of the use of PICS bags
If bags would be reused for a second storage season the benefit/cost ratio would increase to 3.7, 5.0 and 6.3

10. Efficacy of PICS on cassava chips
Number of P. truncatus was not significantly different between treatments
Losses were beyond economical levels, exceeding 8% after 6 months of storage
Oxygen levels in both treatments reached 18.69% and 19.12% after 8 months of storage.

11. What have we learned? Hermetic storage technology effective for maize,
In regions with high levels of P. truncatus (more than 1 Pt per kg) precaution about technology
High moisture content of grains in PICS bags can reduce germinability and lead to quality loss
Bags are penetrated from inside to outside
Technology not effective for traditional cassava and yam chips

12. What R&D is missing
Need for low-cost energy efficient dryers to improve grain drying to avoid mycotoxins & moisture meters
Potentially increase effectiveness of PICS bags by including another technology to reduce insect attack (oils, natural substances, ???)
Test PICS bags for other commodities and include further quality parameters (nutrition, processing characteristics, toxins)
All stakeholders need to address the persistent high post-harvest losses (advocacy)