Peach twig borer damage on purple leaf plum
Peach twig borer, Anarsia lineatella, caused this damage on purple leaf plum. Images are from third week in July.
Useful websites:
WSU Orchard Pest Management Online: Peach twig borer Nice images, useful phenological and management information.
UC IPM Online: Peach twig borer
Berry, R. E. 1998. Peach Twig Borer. Insect and Mites of Economic Importance in the Pacific Northwest, 2nd Ed.