Insect and Disease Pests of Southern Hardwoods

In natural stands, trunk borers are economically the most serious insect pests. The larvae construct galleries in the trunks of living trees, causing the greatest damage in the lower portion (Beal 1952; Hay and Wootten 1955). The quality of the butt log, which is potentially the most valuable portion of the tree, is greatly reduced. Oaks suffer more damage than other hardwoods in the South (Hay and Wootten 1955, Putnam et al. 1960). Wood value is greatly reduced by the holes, but little physical weakening or growth loss occurs. In addition to the damage resulting from the galleries of the large trunk borers, secondary damage around holes is caused by wood-rot fungi, by carpenter ants, and by woodpeckers preying on the grubs CMorris 1965, Solomon 1969). High-quality veneer and furniture-grade lumber cannot be cut from borer-damaged trees. Mill-grade studies (Morris 1964) showed that insectcaused defects in the trunks of living southern oaks resulted in lumber degrade and loss averaging about $20 M b.m. Such losses applied to the approximately 3 billion board feet of oak lumber sawn annually in the South indicate 60 million dollars' worth of damage per year.