The effectiveness of phytosanitation was investigated by periodic removal and counting of infested kolanuts. Effect of burying nuts in different media on infestation was investigated by storing kolanuts in humus soil, river sand, sawdust and in storage baskets without any medium (control) for four weeks. The sorting and removal of infested nuts at weekly intervals resulted in a significantly lower (P < 0.05) infestation (20%) than sorting at monthly intervals (52.8%). The control treatment differed significantly (P < 0.05) from all the other treatments as 92% of the nuts had become infested by the end of the 4th month. The highest rate of weevil emergence in the control occurred between 6 and 12 weeks of burying (23.3 to 84.5). This was followed by the nuts buried in dry and wet topsoil, which recorded high rate of weevil emergence at 6 and 8 weeks of burying (11.5 to 15.3 and 14.5 to 17.3 respectively). The rate of weevil development in the soaked nuts progressed steadily till the 4th week with mean adult emergence of 6.75 to 9.5 before it was drastically reduced from the 6th week. Storage of unskinned kolanuts in sawdust, river sand or top soil can therefore be recommended as a safe, cheap, easy-to-apply and effective method of control of weevils during storage. These media successfully acted as physical barrier, which disallowed egg laying and feeding by the first generation of adult weevils that emerged during storage.
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