A laboratory experiment was conducted during October 2011 to compare the insecticidal effects of neem seed kernels ethanolic extracts prepared from neem products of five years (2007, 2008, 2009, 2010 and 2011) against the 3^rd instar larvae of Trogoderma granarium. Three concentrations (5%, 2.5% and 1.25%) were used from each product extract. The results of larval mortalities were recorded at four weekly intervals (7, 14, 21 and 30 days) post treatments. Although, some variations were observed between treatments after one week, no significant differences were detected. After 2 weeks, the highest rates (5%) of three products (2008, 2009 and 2010) extracts showed significantly the highest mortality percents, with the former one being relatively the best. After the 3^rd and 4^th weeks the three previous treatments also kept comparably superior significant effects, but the product of the year 2010 was relatively the best. It is clear that the fresh seeds (product of 2011) and the oldest seeds (2007) were the least effective during all counts. In general, all extracts exerted increased mortalities in relation to concentrations and exposure time. No significant variations were detected regarding seeds damage due to the short period of the study. Hence, it can be concluded that storage of neem berries at periods ranging from one to three years under normal room temperature were optimum for obtaining the highest effect of ethanol extract from seed kernels.   

Keywords: Neem, Storage durations, Seeds age, Insecticidal effect, Trogoderma granarium.

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