Loss Assessment of Stored Maize at Different Storage Durations and Maize Weevil Densities

Aims: The extent of stored grain losses depends on varieties and duration of storage, and most of the quantitative losses are attributed to insect pest infestations. The study was conducted to determine the damage caused by Sitophilus zeamais on maize stored at different durations.

Methodology: Sitophilus zeamais at four varying population densities (5, 10, 15, 20 adults) and four storage durations (30, 60, 90 and 120 days) reared on 200 g sample of Jeka maize variety was kept in glass jars covered with muslin cloth in a 4 x 4 factorial fitted in a completely ramdomised design with four replicates at room temperature for 120 days.

Results: Weight loss, seed damage and weight of dust caused by S. zeamais on maize seeds at 5-insect and 20-insect levels were statistically similar at 30 and 120 days but show significant difference at 60 days after storage. Sitophilus zeamais population continued to grow exponentially on maize grains after 120 days of storage, indicating that factors are not limiting, thereby causing significant losses to stored grains. Temperature and relative humidity were found to affect insect population growth positively (r = 0.73 and r = 0.70, respectively).

Conclusion: The study concluded that S. zeamais, which is a major pest in The Gambia, in the absence of control measures at any number of infestations greater than 5 weevils could result to severe damage to stored seeds.