Triple layer bags consist of two gas-proof inner bags, one inside the other. For protection against physical damage these are placed inside a much tougher, open weave polypropylene (PP) bag. After filling they are tied shut with string. The inner bags are gas-tight (hermetic) so that some weeks after being filled with grain and tightly closed, a modified atmosphere is created that will kill insect pests. Triple bags usually have a capacity of 50 or 100kg. The name PICS bag is an acronym based on 'Purdue Improved Cowpea Crop Storage'.
CEREALS - Maize (Benin, Ghana, Kenya, Niger, Rwanda, Malawi, Senegal, Tanzania, Zimbabwe), millet (Senegal), sorghum (Senegal, Tanzania, Zimbabwe), rice (Tanzania), cowpea (Benin, Burkina Faso, Cameroon, Ghana, Mali, Niger, Nigeria, Togo, Senegal, Chad)
PULSES - common beans (Kenya), dolicos beans (Kenya), green gram (Kenya, Uganda and Tanzania) , groundnut seeds (Senegal), pigeonpeas (Kenya, Tanzania). In West Africa, mostly cowpea due to high value.
Purdue University - All pulses and cereals we have tested are well protected (Maize, sorghum, wheat, millet, rice, common bean, cowpea, peanut, bambara groundnuts, pigeon pea, mung bean, chickpea, sesame, etc.)
Two inner layers of high density polyethylene (HDPE) 80 microns thick held inside a third bag made of woven polypropylene
Bags have been manufactured in the following African countries: Burkina Faso - Fasoplast (Ouagadouogou); Ethiopia - SePCo (Addis); Ghana - Polytank (Accra); Kenya - Wonderpack (Nairobi), Bell Industries; Mali - EmbalMali (Bamako), Emballage Miankala ((Koutiala); Malawi - Polypack (Blantyre); Nigeria - Lela Agro (Kano); Rwanda - Ecoplastic (Kigali); Senegal -COFISAC(Dakar); Tanzania - PPTL (Tanga); Uganda - Luuka Plastics (Kampala); Zambia - Polythene Products; Zimbabwe - City Plastics (Harare). Also produced in Afganistan, India and Nepal.
Median life 3 years. In Niger, when cowpea is stored in PICS bags 79% of bags are in use at the end of the third year; usage declines fairly sharply thereafter.
Storage of crops not requiring hermetic storage, making plastic ropes and mats, rain-shedding wearables, baby diaper covers, as roofing, storage of clothing, as window covers.
The PICS bag has been the subject of numerous marketing campaigns in different countries, organised by the PICS project. Since 2007: Senegal, Mali, Burkina Faso, Ghana, Togo, Benin, Nigeria, Niger, Chad, and Cameroon. Since 2012: Afghanistan Since 2013: Rwanda, Kenya, Nepal, Burundi, and D.R. Congo Since 2014: Tanzania, Uganda, Ethiopia, Malawi, and Zambia Since 2015: Sierra Leone. Not yet promoted in Zimbabwe.
The marketing or promotion campaigns for PICS bags used a wide range of approaches including: village or market place demonstrations during or just prior to the harvest season, posters, leaflets, banners, cell phone videos, radio spots, TV spots, newspaper articles, drama, community radio training, agricultural exhibitions and events such as food safety week, or launch ceremonies by Ministers of Agriculture. They have been further promoted through their inclusion in collaborative on-farm storage trials by researchers, extension agents and farmers. Most felt it was too early to judge whether these promotion approaches have been successful. Some feel the campaigns lack a long-term sustained promotion strategy, and that the distribution network is the problem. Others feel adoption is now beginning to pick up.
Trainers were trained in a 2-day ToT event. This covered the major do’s and don’t’s of PICS bag use, and explained the mode of action and taught them how to answer typical questions that arise. The trainers then conducted village training activities in each focal village. Trainers implemented 1 to 2 hour demonstrations to teach farmers how to use PICS bags. Grain was loaded into PICS bags by pilot farmers, then the bags were stored for 4 to 6 months, after which ‘open-the bag’ public events were organized (and sometimes televised) to assess the effectiveness of the technology in preventing losses. In some locations the training/demonstration session included: review of storage pests of major crops; management methods of stored products; the use of PICS bags to address post-harvest losses (demonstration); mode of action of PICS bags; efficacy of PICS bags for grain and seed storage; assessing grain quality during storage; the economics of the PICS bags (cost: benefit analysis). In Rwanda training was reported to target agro-dealers as well as trainers and farmers.
Despite all the promotion, PICS bags adoption was not felt to be widespread yet. Some felt an adoption study was needed to be able to answer this point. The PICS project team reported that 4.5 million PICS bags have been produced and sold by plastics manufacturers and input dealers in SSA, and the PICS bag market is now expanding into Asia. Lack of availability of PICS bags at local level was viewed as a constraint to adoption, since if it was available locally then it was being adopted. See Moussa et al. (2014) Adoption of on-farm of hermetic storage for cowpea in West and Central Africa in 2012. Journal of Stored Products Research, 58, 77-86.
WFP Zambia is promoting PICS bag for cowpea storage in schools (have purchased about 10,000 bags), and for school feeding programs in Mali. They are also being used by school feeding programs in Northern Ghana. In West Africa, they are being used in community grain stores and by some government food security agencies (e.g. Niger OPVN who have purchased about 800,000 bags), and relief organisations, although emergency situations typically use large scale aggregators. However, procurement procedures for public schools, hospitals, military centres and prisons are often very bureaucratic which hinders adoption of PICS bags.
In general - PICS bags are easy to use, convenient and do not require the use of a grain protectant such as dilute dust insecticide. The technology is scale neutral- e.g. a 100kg bag capacity can effectively store 20 kg without any losses. Large quantities of grain can be stored using PICS bags (OPVN Niger stored 80,000 tons of cowpea in PICS bags). Also, the bags can be locally manufactured in most developing countries where there are plastic manufacturers. Rwanda - Can keep the grain longer than in the case of insecticide treatment, the grain is healthy for human consumption. The bags can be kept inside the house. Kenya - The two different layers of plastic provide greater insect deterrents. It is simple to use.
The PICS bags can be perforated by rodents. Zimbabwe - The current version from US is too big compared to what the farmers are used to (50kg). If used by farmers to full capacity, handling might be a problem because of the weight. Prone to LGB damage and possible rodent damage so that the bags are no longer hermetic. Rwanda - It requires technical know how. Cannot be used in large-scale storage as a large bag stack would appear to be unstable. Quality control of bags at manufacture company cannot be guaranteed and it is important that they are genuine PICS bags, i.e. that they are manufactured using high density polyethylene (HDPE) otherwise they have poor hermetic properties and are more likely to be penetrated by insects.