Ioberlinia scheffleriHarms is a common tree in the East Usambara Mountains of Tanganyika, andParinari excelsasubsp.holstiiis the dominant tree of the Kalinzu Forest and adjacent areas of Uganda. The utilization of these two species, however, is severely curtailed by borer damage. The infestations to which the living trees are subject, results in serious losses in volume on conversion and frequently renders trees unacceptable for milling. In certain areas of the Usambaras 87 per cent of all commercial sizeIsoberliniatrees are borer-infested. In parts of the Kalinzu concessions 98 per cent of exploitableParinaritrees are attacked.