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

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

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

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 ± 16.33 Aa 19.41 ± 1.82 Bb 90.81 ± 9.18 Aa 22.27 ± 2.00 Bb 17.74 ± 1.16 Db 82.92 ± 14.38 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

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

Means numbers of holes on PICS Bag and PPB PsB PPB

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 ± 33.28 Ba 238.75 ± 2.38 Ba 147.05 ± 7.82 Ba 355.05 ± 14.26 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 < 0.0001) In hermetic storage, P. truncatus was found ONLY when maize was artificially infested whereas in the control it all bags had this species

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%.

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

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.

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

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)