The study was conducted to investigate the phenology of G. molesta adult, and to develop and validate the degree-day model of G. molesta in apple orchards. It was known that G. molesta is a multi-voltine insect depending on temperature and geographic location. G. molesta damage to many economically important fruit trees such as apple and pear. Data collection was carried out in five apple-growing location (Chungju, Bonghwa, Andong, Uiseong, and Geochang) and at least three commercial orchards of each location was selected for collecting data in 2011 and 2012. The commercial pheromone monitoring trap (GreenAgroTech) was used to investigate the flight phenology of G. molesta. The relationships between degree-day accumulated above the low temperature threshold and cumulative proportion of accumulated G. molesta caught per generation were used to predict the phenology of G. molesta. The phenology of G. molesta per generation was analyzed by Weibull 2-parameter function. The generation of G. molesta was depending on local environmental conditions, specially temperature. The first flight of G. molesta adult in Chungju was later than other places. The average number of G. molesta caught in Uiseong was significanlty decreased from 2011 to 2012. The occurrence of G. molesta adult was explained well by degree-day model using Weibull 2 parameter function. The developed model system could be applied to manage G. molesta population in apple orchards.

Grapholita molesta is one of economically important pests in pear orchards and has four to five generations per year depending on food resources, geographic location, and temperature. The overwintering larvae of G. molesta pupate early in the spring and new adults start to flight for several reasons such as mating, seeking resources and oviposition. The study was conducted to develop the full seasonal phenology model of G. molesta and to investigate the phenology of G. molesta adult in pear orchards. Data collection was carried out in five pear-growing location (Anseong, Icheon, Sangju, Ulju and Naju). Three commercial orchards of each location was selected for collecting data in 2011 and 2012. The flight phenology of G. molesta was investigated by the commercial pheromone monitoring trap (GreenAgroTech) once per week. The phenology of G. molesta per generation was predicted by the relationships between degree-day accumulation above the low temperature threshold and cumulative proportion of accumulated moth caught per generation. The phenology of G. molesta per generation was calculated by Weibull 2-parameter function. Although the latitude of Sangju was higher than that of Naju, the first flight of G. molesta adult from two orchards was similar. The average number of G. molesta adult caught in every pear orchards was increased from 2011 to 2012. The occurrence of G. molesta adult was explained well by degree-day model using Weibull 2-parameter function.