Cotonou — Insect pests that attack stored rice are causing financial losses to farmers in Benin, researchers report in the first such study of the crop in the country. But they also found significant regional differences in damage.
According to their paper, published in the Journal of Applied Sciences earlier this year (21 February), rice production in the past was not high enough in Benin to justify long-term storage on farms so insect damage was less significant.
But since 2009, rice production has increased in many African countries and storage has become common practice. In 2012, Benin recorded 150,000 tonnes of stored paddy rice.
The researchers sampled 65 rice stores around the country and carried out a survey among farmers to determine their views on the economic importance of insect damage.
For a storage period of four to six months, they found financial losses were up to 21,315 Francs of the African Financial Community (around US$42) per tonne of stored rice in the south of the country and up to US$16 in the north.
By weight, they reported losses of about 5.5 per cent after six months of storage in the south, four per cent in the central region and 1.6 per cent in the north.
The damage caused by insect pests includes a reduction in nutritional value, grain discolouration, reduced germination, bad odour and taste, and the formation of mycotoxins that can cause serious illness in consumers, says lead author Abou Togola, an entomologist at the Africa Rice Centre (AfricaRice) in Benin.
"Based on current levels of losses, the country could lose hundreds of millions of francs because of insect damage," he tells SciDev.Net.
AfricaRice has developed techniques now being introduced to farmers to help them reduce pests in rice stocks.
Togola says that technologies for impregnating jute packaging with insecticide are being tested and the spread of pests could be limited by "adopting some key practices such as ensuring proper drying before storage, reducing humidity levels, machining before storage - because some primary pests are unable to live on husked rice - and parboiling rice".
But Béla Teeken, a researcher at the technology and agrarian development group at Wageningen University, the Netherlands, says that the study missed the opportunity to look at possible differences in farming practices between the country's regions.
"The difference in pest damage might not only be related to humidity but also to the strategies of farmers. A study of farming styles might shed light on this. Apart from this, it could also be related to the varieties of rice being used," Teeken says.
This article has been produced by SciDev.Net's Sub-Saharan Africa desk.