Peach twig borer

You will find dead shoot tips with oozing gum on peach, nectarine, apricot, and plum trees beginning at spring budbreak. Larvae bore into new shoots, feeding until late spring, leaving frass and gum accumulation at entry holes. Larvae overwinter in hibernacula under bark in limb crotches. This borer produces three complete generations annually in Washington. Twig damage is most obvious on young trees.

Cut out flagged twigs below the bored area, removing larvae inside. Apply dormant sprays of spinetoram or spinosad in late winter to kill overwintering larvae. Time growing season sprays at pre-bloom and petal fall stages. Hand-remove larval galleries when populations are light.