Lesser peachtree borer

Systematic position: The Lesser peachtree borer (Synanthedon pictipes) is a member of the order Lepidoptera and the family Sesiidae (clearwing moths). Unlike its relative, the Peachtree borer, this species primarily infests the upper trunk and scaffold branches of trees, rather than the base near the ground.

Host plants: This pest is a serious threat to various stone fruit species. It commonly affects peaches, nectarines, cherries, plums, and apricots. It prefers trees that have existing wounds, sunscald damage, or poor pruning cuts, as these provide entry points for the larvae.

Biology and life cycle: The insect completes its life cycle by passing through egg, larval, pupal, and adult stages. Adult moths are diurnal and resemble wasps. Females lay eggs on the bark near wounds. Once the eggs hatch, the larvae tunnel into the inner bark to feed on the cambium layer, where they overwinter if necessary before pupating in the spring.

Damage and economic importance: The larval stage is responsible for all damage. By tunneling under the bark, they disrupt the tree's vascular system, leading to gummosis (excessive sap flow) at the entry holes. Heavy infestations weaken the tree, reduce fruit production, cause branch dieback, and create entryways for pathogens like Cytospora canker.

Control measures: Management involves an integrated approach focused on orchard sanitation and chemical suppression. Maintaining tree health through proper irrigation and balanced fertilization is the first line of defense. Pruning should be performed carefully to avoid large, jagged wounds. Insecticides can be applied to the trunk during peak moth flight times, and mating disruption using pheromones is an effective tool for commercial orchards.

• Avoid mechanical damage to trunks during mowing or cultivation.
• Paint tree trunks with white latex paint to reduce sunscald.
• Promptly remove and destroy heavily infested branches.
• Monitor pest activity using Pheromone traps to time treatments.