Within-Orchard and Within-Tree Distributions of Peach Twig Borer (Lepidoptera: Gelechiidae) Damage to Peaches

Abstract

The distribution of peach, Prunus persfca (L.) Batsch., fruit damage caused by the peach twig borer, Anarsfa lineatella Zeller, in orchards treated with pheromone dispensers for control of the oriental fruit moth, Grapholita molesta (Busck), was studied in four California peach orchards. Fruit damage in the tops of trees was significantly greater than fruit damage in the lower half of the tree canopy. Fruit damage at harvest was significantly greater than fruit damage at sampling dates up to 4 wk earlier in three of four orchards. Fruit damage in trees located on an orchard border was significantly greater than fruit damage in trees located in the center of the orchard. Fruit damage in trees located on the border row adjacent to an external source of A. lineatella was significantly greater than fruit damage in trees located in rows farther away from the external source. Fruit damage in the south tree quadrant was greater than fruit damage in at least one other tree quadrant in three of four orchards; this difference was significant in two of the three orchards. Results suggest that a simple fruit monitoring program can be used for peach orchards where control methods applied for other pests would not protect the crop from A. lineatella late in the season.