Analysis of Occurrence Pattern of the Pear Psylla, Cacopsylla pyricola, in the Pear Exporting Complex

Abstract

One of the most serious insect pests for pear is the pear psylla, Cacopsylla pyricola Foerster (Hemiptera: Psyllidae). Due to the nature of the overwintering adults that spend winter time underneath bark the control of the pear psylla is very difficult. Thus, one of the effective control methods recommended includes a spray of machine oil emulsion, when overwintering adults start to move upward to tree branches and when eggs that have been oviposited by overwintered adult females are observed. Previously, the model that predicts the onset date of upward-movement and oviposition has been proposed on the basis of weather and ecological information of the pear psylla, but it based the information obtained from the central region of Korea, requiring the data from the southern part of Korea that is warmer than central region. In this study, therefore, we investigated annual occurrence of the pear psylla by weekly field observation and meteorological data obtained by automatic weather station (AWS) that has been installed at Bonghwang in Naju City. As a result, we found 14 days difference for the onset of upward-movement at maximum and 7 days difference for the first observation of eggs at Naju City compared with the existing prediction. Consequently, additional study for prediction model and resultant modification of the control strategy is needed, targeting the pear psylla populations occurring in southern region of Korea.