We had great respect for Ralph's knowledge and expertise in apple pest management. P.O. Box 479, Columbus, OH 43216. They often infest peach trees, as well as apricot, cherry, and plum trees. The PTB is primarily a pest of young trees, the LPTB of older trees. Moths of the borers lay their eggs on the bark.
Pheromone traps indicate moth emergence and aid in proper timing of spray applications.
If only PTB is present and it is on a late-maturing variety, apply a trunk spray during the first week of August. Apply at least 1 gallon per tree. If only LPTB is present, either a preharvest spray on late-maturing varieties or a postharvest spray may be made as described above. Thoroughly wet all bark areas from ground level to scaffold limbs. Lorsban 50 WP is labeled for borer control on sour cherry, but not on sweet cherry, peach, or nectarine.