Volatile organic compounds in healthy and Opisina arenosella Walker (Lepidoptera: Oecophoridae) infested leaves of coconut palms

Abstract

An exploratory study, for the first time, was conducted to identify the volatile organic compounds (VOCs) present in dichloromethane extracts of uninfested and O. arenosella infested leaves of three varieties of coconut palms, viz. WCT, MGD and COD, as well as from the frass produced by the caterpillars while feeding on these varieties. Many VOCs reported from other plant species and having specific functions in plant-plant and plant-insect interactions were identified in the leaf material. Green leaf volatiles (Z)-3-hexen-1-ol and (Z)-3-hexen-1-ol acetate, acetophenone and nonanal were found in both uninfested and infested leaves. Differences in VOCs were observed between different varieties of coconut plants and between infested and uninfested plants of these varieties. The VOCs identified in insect frass included 6-hydroxy-2-hexanone, n-hexadecanoic acid, b-pinene, b-myrcene, hexahydrofarnesyl acetone, acetophenone and undecane. Indicated possible roles of the identified VOCs based on existing reports for other plant species.