Effects of corn varieties on the growth of sitophilus oryzae populations

Abstract

This paper is concerned with the effects of different corn varieties on the development of populations of Sitophilus oryzae (L., 1763) (Col., Curculionidae) under laboratory conditions. The experiment was established in a completely randomized design in a factorial scheme, with three replications. The C-111 hybrid, Piranão and Flint Composto varieties were infested with 0; 5; 10 and 20 pairs of insects and stored for 60; 105 and 150 days. Analysis of variance confirmed the number of insects that emerged from C-111 hybrid was significantly greater than Flint Composto which did not differ statistically from the Piranão variety. The S. oryzae population increased with the initial infestation and storage period, except for the hybrid which caused a decrease in the number of alive adults after 105 days of storing period with the highest initial population, due to the feeding competition in a restricted nutritional substratum. The hardness of the grains was not the only factor affecting the populational development of this species. The carbohydrates content had an important role as a favorable factor for insects reproduction.