Evaluation of the effect of interspecific competition by larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) and maize weevil, Sitophilus zeamais (Mots.) (Coleoptera: Curculionidae) on damage to maize grains

Abstract : This study evaluated the effect of interspecific competition between the larger grain borer ? Prostephanus truncatus and maize weevil - Sitophilus zeamais on damage by the insects to infested maize grains. 50 g maize grains was weighed into 250 cm3 kliner jars and infested with adult LGB and S. zeamais of between 1 ? 10 days old as follows: 50 g maize + 6 pairs of LGB, 50 g maize + 6 pairs of S. zeamais, 50 g maize + 3 pairs of LGB + 3 pairs of S. zeamais, 50 g maize + 4 pairs of LGB + 2 pairs of S. zeamais, 50 g maize + 2 pairs of LGB + 4 pairs of S. zeamais, 50 g maize + No LGB + No S. zeamais. At 90 days post-infestation, the following data were taken: weight of grain dust (g), final weight of grains (g), weight of damage and undamaged grains (g), number of living adults and number of adult mortality. The result indicated a significantly (p < 0.05) higher % grain damage (91.33) and grain dust (2.42 gm) in maize grains solely infested with S. zeamais. In treatments with mixed insect infestation, treatment with higher population of S. zeamais (50 g maize grains + 2 pairs of LGB + 4 pairs of S. zeamais) had a significantly (p < 0.05) higher % damage (42.90) than other treatments of mixed insects infestation. However, a significantly (p < 0.05) higher % weight loss (5.01) and weight of grain dust (2.51 gm) was obtained in treatment with higher population of LGB (50g maize grains + 4 pairs LGB + 2 pairs S. zeamais). Mortality of adult LGB (7.3) was significantly (p < 0.05) higher in treatment with higher population of LGB (50 g maize grains + 4 pairs LGB + 2 pairs S. zeamais). In two of the treatments with mixed insect infestation, (3 pairs LGB + 3 pairs S. zeamais) and (2 pairs LGB + 4 pairs S. zeamais), all the introduced LGB died and no larvae nor pupae was seen in the treatments. The study indicated the ability of S. zeamais to suppress the activities of LGB in interspecific competition
Keyword : P. truncatus, S. zeamais, Z. mays, Interspecific competition, infestation
Author(s) : , A. A. Osipitan, T. J. Adebowale, I. G. Mohammed, D. I. Adekanmbi
Downloads : 1261


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