Post-harvest screening for maize weevil resistance in different types of corn hybrid seeds

A total of nine commercial field and sweet corn hybrids were screened for evidence of maize weevil (Sitophilus zeamais Motschulsky) (Coleoptera: Curculionidae) resistance.  One hundred grams of open pollinated kernels from each hybrid were pre-conditioned to the same moisture content, and then infested with ten maize weevils per jar. The treatments were arranged in a randomized completely block design with five replications (or jars) of each hybrid as the block factor, and the experiment was conducted twice. Founding adults used for initial infestation were removed after 3 wk, and trials were terminated 83 d after the initial infestation. Offspring per founding female, the number of insect damaged kernels, and grain weight loss were compared among the hybrids. Data showed great differences in susceptibility among the hybrids, and sweet corn hybrids were generally more susceptible than the field corn hybrids. Investigations into the mechanisms of resistance are underway.