Peach Twig Borer
Common Name: Peach Twig Borer
Latin Name: Anarsia lineatella
Main Host(s): Fruit and nut trees such as peaches, nectarines, prunes, plums, apricots, almonds
Peach Twig Borer (PTB) is a pest common to the Mediterranean area but also to many fruit and nut growing areas around the world, from North America to Europe and Asia, with the exception of Australia and Japan. Its primary hosts are stone fruits such as peaches, nectarines and prunes, but nut trees such as almonds are susceptible as well.
Between one to four generations of PTB occur depending on the climate of the region. Young PTB larvae overwinter as young first or second stage larvae in shelters called hibernacula. On second- and third-year wood, they will generally emerge in early spring as daytime temperatures begin to hit about 15C (60F). Degree-day models have been developed by scientists to predict PTB emergence. Pupae can be found beneath bark or in crevices. Females lay egg masses of about 80-90 eggs on shoots, fruit and underside of leaves. The eggs hatch in 5-8 days, or longer in cooler areas.
The overwintering larvae of this species feed on buds and leaves and enter the young shoots, causing “flagging”. The summer larval generations feed on immature fruits and shoots.
Impact & Damage
Summer generations of peach twig borer infest the fruit and can cause considerable economic damage. The “flagging”, i.e. snapping of young shoots by the overwintering larvae boring into the terminals can cause stunting and reduce the vigor of young trees.
Scouting for larvae in their hibernacula will help establish pest control timing for individual orchard plots. A spray program is initiated when 20% emergence is observed. DiPel® is an excellent control for PTB and unlike some chemicals used against this pest, DiPel is completely harmless to bees. A second DiPel application should be made at 80% to 100% emergence, about a week later under normal conditions. Using biorational products, like DiPel, in early season can prevent flare up of secondary pests during the summer. Pheromone traps are used to monitor the adult moth population and predict egg laying of the summer generation(s).
References & Sources:
Pesticides and Beneficial Organisms; IOBC/wprs Bulletin Vol. 35, 2008; pp. 44-50