Abstract:
The dynamics of infestation and losses of stored maize due to the larger grain borer
(Prostephanus truncatus Horn) and maize weevils (Sitophilus zeamais Motschulsky) were
investigated in Tanzania. In single species populations, significantly higher maize
damage (P 0.05) was caused by P. truncatus (23.3%) compared to S. zeamais (6.4%).
Weight losses caused by P. truncatus were higher (12.7%) than for S. zeamais (6.7%)
under similar conditions. A higher proportion of P. truncatus in the initial infestation
population led to significantly higher ( 0.05) maize damage compared to equal or
higher proportions of S. zeamais. Irrespective of the initial number of S. zeamais,
population size increased to levels higher than for P. truncatus. Maize losses in
unimproved storage structures were480% compared to52.5% in improved structures
under natural infestation. Inter-specific competition appeared to influence the dynamics
of infestation, damage levels and weight losses. The first two months of storage were
critical for damaging insect populations to build up.
