The cocoa pod borer, Conopomorpha cramerella (Snellen) (Lepidoptera: Gracillariidae) in Papua New Guinea: its distribution and host plant preference

Abstract

The Cocoa Pod Borer (CPB) moth, Conopomorpha cramerella (Snellen) (Lepidoptera: Gracillariidae) was first detected attacking cocoa in Papua New Guinea in 2006. Attempts to eradicate were unsuccessful and efforts to promulgate intervention strategies in the cocoa farming communities moved slowly due to various constraints. This provided an opportunity for the pest to spread. The pest, by now, has been in the country for more than six years. However, there is no information and work done on the local biological and ecological interactions of the pest and its distribution. This information is prerequisite to development of an effective location-specific integrated pest management strategy (Ls-IPM) for CPB in Papua New Guinea. This work intends to look into some aspects of the biology and ecology of the pest in its recently established local environment. Two main areas of interest this work intend to investigate are: (1) the spread and distribution of the pest after the incursion, and (2) the host plant preferences. Historical information and literature indicated that CPB is native to Southeast Asia where cocoa was introduced into this region in the 16th century by the Spaniards. Since its detection in 2006, the pest has now spread to nine provinces in Papua New Guinea. Evaluation on host plant preferences using a simple improvised olfactometer indicated a significant difference in orientation responses to Theobroma cacao L. than Nephelium lappaceum L. and Pometia pinnata J.R. Forst. & G. Forst. Egg deposition on host plants offered simultaneously also indicated a strong preference for oviposition on T. cacao. The attention of the pest towards T. cacao is a concern for cocoa cultivation. Also the ability of the adults reared purely from T. cacao to lay eggs and orientate towards N. lappaceum and P. pinnata, though not significant, is a serious concern for T. cacao cultivation in Papua New Guinea as N. lappaceum is gradually gaining momentum as an alternative cash crop and P. pinnata is edible and is a potential alternative cash crop and are seen within the vicinity of many smallholder cocoa farming systems.