Insect pests infesting stored pearl millet Pennisetum glaucum (L.) R. Br. in northeastern Nigeria and their damage potential

A survey of the systems used for pearl millet storage, the species of insect pests infesting stored pearl millet and their damage potential, was carried out in 1997/98 in the sudano-sahelian zone of northeastern Nigeria. Polypropylene sacks with a frequency of 65.6% were employed more frequently by farmers for pearl millet storage than rumbus (mud silos), clay pots or underground pits with frequencies of 18.8, 9.4 and 6.3%, respectively. Three species of secondary pests, Tribolium castaneum (Tenebrionidae), Cryptolestes ferrugineus (Cucujidae) and Liposcelis bostrychophilus (Liposcelidae) constituted 47.7, 27.8 and 17.0% of the total number of insects collected from millet sub-samples, respectively; two species of primary pests, Rhyzopertha dominica (Bostrychidae) and Sitophilus zeamais (Curculionidae) constituted 6.8 and 0.6%, respectively. Percentage of damaged pearl millet grains was significantly higher in grains stored in the underground pit storage system (80.1%) than in grains stored in the rumbu (39.2%), clay pot (15.8%) or polypropylene sack (14.0%). Damage by insect pests was significantly higher in grains stored for a longer duration than in grains stored for a relatively short period.