Effects of PICS bags on insect pests of sorghum during long-term storage in Burkina Faso

Antoine Waongo,Fousséni Traore,Malick N Ba,Clémentine Dabire-Binso,Larry L Murdock,Dieudonné Baributsa,Antoine Sanon

doi:10.1016/j.jspr.2019.07.010

Abstract

The PICS bags, originally developed for cowpea storage, were evaluated for sorghum (Sorghum bicolor) preservation. Batches of 25 kg of sorghum grain were stored in 50 kg PICS or polypropylene (PP) bags under ambient conditions for 12 months and assessed for the presence of insect pests and their damage, seed viability and, oxygen and carbon dioxide variations. The grain was incubated for 35 days to assess whether any insects would emerge. After six months of storage, oxygen levels decreased in the PICS bags compared to polypropylene bags. After 12 months of storage, only two pests, Rhyzopertha dominica and Sitophilus zeamais were found in the PICS bags. However, in PP bags there were additional pests including Tribolium castaneum and Oryzeaphilus mercator and Xylocoris flavipes. Grain weight loss and damage caused by these insects in the PP bags were significantly higher compared to those stored in PICS bags. Germination rates of sorghum grains stored in PP bags decreased significantly while no changes were observed in grains stored in PICS bags when compared to the initial germination. After the incubation post storage period, there was a resurgence of R. dominica in sorghum grains from PICS bags but the population levels were significantly lower compared to polypropylene bags. PICS bags preserved the quality and viability of stored sorghum grains and protected it from key insect pests. The PICS technology is effective for long-term sorghum storage but the potential resurgence of insects in low-oxygen environment calls for further research.

Highlights

Agriculture in the Sahel is dominated by the production of traditional grains such as millet [Pennisetum glaucum (L.)] and sorghum [Sorghum bicolor (L.) Moench] (World Bank, 2011)
By the end of the 8-months period, the O2 concentration in the PICS bags decreased by about 8% compared with a 2% decrease in the PP bags (Fig. 1a)
In the meantime the CO2 concentration increased by more than 6% in PICS bags compared to only 0.7% increase in the PP bags (Fig. 1b)

Summary

Introduction

Agriculture in the Sahel is dominated by the production of traditional grains such as millet [Pennisetum glaucum (L.)] and sorghum [Sorghum bicolor (L.) Moench] (World Bank, 2011). In Burkina Faso, sorghum is the predominant cereal. In Burkina Faso, sorghum grains are attacked by several insect pests, with the lesser grain borer Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) being the most important (Waongo et al, 2015). Infestation of stored grains by R. dominica is known to cause losses in both quality (Williams et al, 1981) and quantity (Brower and Tilton, 1973). In Burkina Faso, losses during sorghum storage are estimated to be 6.8% (Loada et al, 2015). Damage to seed and residue produced insect feeding reduce grain quality and decreases the essential amino acid contents (Jood et al, 1995). Damage caused by R. dominica reduce seed viability and seedling vigor (Jilani et al, 1989).

Methods

Results

Conclusion