Peach twig borer, Anarsia lineatella Zeller (Lepidoptera: Gelechiidae), development in Washington and California.

Lower and upper developmental thresholds for Anarsia lineatella Zeller based on egg duration and adult flight were 10 and 3l.1°C, respectively. Generation time ranged from 514 to 612 day-degrees. Adult flight of the winter generation was first observed 118 day-degrees after first pupation of overwinter larvae. Shoot flagging was observed 260 day-degrees after the first moth. The average day-degree duration for each insect stage is given. Parameters are suggested for using the PETE generalized-phenology model.