Low-temperature tolerance of light brown apple moth (LBAM), Epiphyas postvittana

The light brown apple moth (LBAM), Epiphyas postvittana (Walker), is a polyphagous invasive tortricid that was discovered in California in 2006. LBAM is considered a major pest of fruits including apples, grapes, oranges, and pears, and could threaten Washington's apple industry. A 3-month study on the low-temperature tolerance of light brown apple moth was replicated three times from the summer of 2009 to the fall of 2010. All life stages (eggs, larval instars, pupae, and adults) were held in an environmental growth chamber programmed for average winter temperatures and photoperiods from Yakima, Washington. A two-week period decreased temperatures and day length to reproduce fall conditions. Daytime and nighttime temperatures simulated December, January, and February weather data. Subsets were pulled from the environmental chamber every two weeks and held at normal rearing conditions for one day before being evaluated for mortality. All eggs and pupae were held for eclosion prior to evaluation. Surviving larvae were reared on artificial diet under normal laboratory colony conditions and then placed in mating containers upon pupation. Temperature and photoperiod were recorded using data loggers. Results indicate that the adult life stage is least tolerant of overwintering at simulated conditions for Yakima, Washington, achieving complete mortality. Eggs and pupae also experienced total kill. Larvae were most tolerant of the low-temperature treatment, with some later instars surviving and completing normal development. Resulting adults were successfully mated and produced viable offspring in the second replication of the study.