Diversity and community structure of insect pests developing in stored sorghum in the Northern-Sudan ecological zone of Burkina Faso

• Twelve coleopteran and two lepidopteran species developed in sorghum stocks in Burkina Faso.
• Insect diversity is highest in sorghum stored within straw granaries.
• Rhyzopertha dominica (Fabricius) is the most important pest of stored sorghum.

Stored insect pests often create major problems for farmers worldwide. Comprehensive data of insect pests of stored sorghum in Burkina Faso are scarce. Understanding the population structure of insect fauna infesting stored sorghum is important for development of management strategy. Sorghum panicles were collected from January to September 2011 in farmers' granaries in the Northern-Sudanian ecological zone of Burkina Faso to determine the diversity of insect pests and their importance in post-harvest losses. A total of 14 species of insect pests were recorded, including twelve coleopteran and two lepidopteran species. Species diversity peaked between May and September. The highest insect diversity was recorded in sorghum stored in straw granaries and on red coloured grains when compared with that of sorghum stored in mud granaries and on white coloured grains. Rhyzopertha dominica (Fabricius) appears to be the primary insect pest followed by secondary pests including Oryzaephilus mercator (Fauvel), Cryptolestes ferrugineus (Stephens) and Sitophilus zeamais (Motschulsky). The distribution pattern of the pests in granaries corresponds to the Mandelbrot model in which colonization of species in an environment depends on the physical conditions of that environment and on the species currently present, which suggest a progressive colonization occurs in waves with stocks of grain.