A Postharvest Control Technique of the Oriental Fruit Moth, Grapholita molesta, Infesting Apples Using CATTS

Abstract

Postharvest insect pest control is necessary for agricultural industry including domestic consumer markets and exporting products to meet quarantine issue. Especially, the organic or environmentally friendly agricultural products do not fit to the traditional chemical postharvest treatments mostly using methyl bromide. As an alternative, a physical treatment called CATTS (controlled atmosphere and temperature treatment) has been developed to control various insect and mite pests on apple and several stone fruits. This study was designed to determine the CATTS conditions to control the oriental fruit moth, Grapholita molesta, which is restricted in exporting the infested apples. To apply CATTS on this insect pest, the most heat-tolerant stage was determined. Among the immature stages locating on the fruits, the fifth instar larvae were the most tolerant to 44℃ for 20 min. The ramping rate (the time to increase chamber temperature from 25℃ to 46℃) was positively correlated with the CATTS efficiency under 15% CO2 and 1% O2. After the ramping step, the duration of CATTS was positively correlated with CATTS efficiency. In addition, the CATTS efficiency was highly dependent on the fruit internal temperature at 44℃. From all these parameters, we developed a standard protocol yielding 100% control efficiency of CATTS against apples infested by 4,378 larvae including 2,104 fifth instar individuals.