Adult activity may begin as early as mid-June but primarily occurs during July and August. After mating, the female moth lays up to 400 eggs on the bark of the lower trunk and in soil cracks near the tree base. Eggs generally hatch in about 10 days. External evidence of peach tree borer tunneling is a wet spot on the bark or the presence of oozing, gummy sap. The sap is clear or translucent and often dark from the sawdust-like excrement of the insect.
Most injuries occur along the lower trunk beneath the soil line.
Lower branches rarely receive injuries. Preventive Sprays Peach tree borer can be difficult to control because insecticides cannot reach the damaging larvae after they move under the bark. The most effective controls are preventive insecticide applications at the vulnerable egg and early larval stages, while the insect is on the tree bark. In Colorado, egg laying occurs during the middle of the growing season. In warmer areas, it may begin July 1 and continue into September.