Analyse de la susceptibilité de sept cultivars de maïs aux attaques du Grand Capucin, Prostephanus truncatus, Horn. (Coleoptera: Bostrichidae)

Abstract

To prevent serious post-harvest losses in corn by the Larger Grain Borer, Prostephanus truncatus (Coleoptera: Bostrichidae) in the sub-saharan Africa, kernel resistance mechanisms to this insect were analyzed. Kernels of seven cultivars from the International Centre for Corn and Wheat Improvement (CIMMYT, Mexico) were analyzed for their physical characteristics and their biochemical properties. Also, grain damage and biology of the borer were recorded on intact kernels. Excellent correlations were observed between hardness and adult mortality and oviposition. The quality of the endosperm appeared to be determinant of levels of susceptibility. Unlike what was noted with Sitophilus zeamais (Serratos, 1987), lipids appear to stimulate Prostephanus truncatus activities and development, and the estimated protein content did not present significant correlations. Among the three endogeneous phenolic acids in corn kernels, ferulic, sinapic and p-coumaric, the latter presented very significant and negative correlations with damage and with oviposition rate. (Abstract shortened by UMI.)