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The mechanism of resistance in maize to the stored product insects such as the maize weevil (MW), Sitophilus zeamais Motsch and the larger grain borer (LGB), Prostephanus truncatus Horn has been investigated in relation to secondary chemistry and other biochemical and physical characteristics of maize genotypes. Performance parameters of weevils (number of eggs laid, number of progeny, Dobie index, grain consumption) were negatively and significantly correlated (r=-0.8, P= 0.05) to the most abundant phenolic of grain, E-ferulic acid. With P. truncatus, the weight loss of grain also showed a negative correlation with E-ferulic acid while percent damage of kernels by insects was negatively correlated to p-coumaric acid. These phenolic acids were found in highest concentration in the pericarp and cell walls of the endosperm by fluorescence microscopy. Phenolic acid content was also found to correlate strongly with hardness of the grain, which may be related to the mechanical contributions of phenolic dimers to cereal cell wall strength. In the aleurone layer phenolic acid amines have been detected that have toxic effects on insects.