Cold hardiness of the light brown apple moth: Assessing the rsk of etablishment in the nrthern U.S

The Light Brown Apple Moth, Epiphyas postvittana, is a highly invasive pest, and recently invaded California. Recent risk assessments for E. postvittana establishment in other U.S. states have been inconclusive, particularly for the Midwest region where many potential host plants of the pest occur (e.g., apples, alfalfa). Preliminary data indicated a relatively high level of cold hardiness in E. postvittana larvae and pupae. Therefore, the aim of this study was to improve our understanding of the capability of this species to survive low temperatures, which can then be used to assess the suitability of establishment of this pest in the northern states. Two indices of cold hardiness, the supercooling point (SCP), and lower lethal temperature (LLT) are reported here for selected larval instars and pupae. Measurements of SCP followed established protocols, with each insect cooled at a rate of ca. 1°C/min. The SCP is the lowest temperature recorded before detection of the exotherm. In brief, the SCPs for larvae ranged from -14 to -24°C, depending on instar; pupae ranged from ca. -15 to -17°C. Results for LLT showed a similar pattern. Parameter estimates from this study, along with other life history parameters will be used to develop an ecophysiological model, to create maps for risk of establishment and persistence of the pest in the contiguous United States.