Mahogany shoot borer, Hypsipyla robusta, is a serious pest of high quality meliaceous timber trees, and no effective method of control has been developed so far. We observed that two experimental plantations of mahogany (Swietenia macrophylla) enclosed by acacia trees (Acacia mangium) were not attacked by the borer for three years in Benakat, South Sumatra, where the attack by the borer had always occurred in mahogany plantations. This protection method could be promising, though its effectiveness must be reconfirmed by further replication of the experiments.