Identification, Synthesis and Biological Testing of Semiochemicals for Fruitworm Moths (Carposinidae)

Abstract

Semiochemicals are chemical signals that organisms use to communicate with each other in their environment. This project explored the semiochemicals of two pest fruitworm moths (Carposinidae), Heterocrossa rubophaga (raspberry bud moth) and Coscinoptycha improbana (guava moth). The project looked at three distinct areas of communication: pheromones and their analogues, host plant volatiles, and herbivore induced plant volatiles (HIPVs). The aim of these studies was to improve the general understanding of carposinid moth semiochemistry and identify potential pest management tools. A new pheromone component, (7Z)-tricosene, was identified for raspberry bud moth. In field trapping trials it was unattractive alone, but when applied in combination with the previously identified pheromone it over doubled the catch of male moths. Concomitantly, an ester pheromone analogue, (4Z)-heptyl undecenoate was identified as a potential mating disruption tool, providing 95% trap shutdown in field trials with raspberry bud moth pheromone baited traps. Two ester pheromone analogues, (4Z)-heptyl undecenoate, and (2Z)-nonenyl nonanoate, gave electrophysiological responses from the male guava moth, yet neither analogue showed any significant effects in field trapping trials. Host plant volatiles from Syzygium paniculatum (magenta lilly pilly) and Acca sellowiana ‘Kakariki’ (feijoa) showed 12 antennally active compounds in electrophysiological testing with female guava moth. Of these compounds, three were common to both host plant species. Female attractant lures were formulated from these compounds and field-tested. Methyl benzoate lures were found to be weakly attractive to female guava moth. Raspberry bud moth host plant volatiles were produced in such low amounts that there was insufficient material for antennal testing and female attractant development. For the HIPVs, an effect was only observed with the raspberry bud moth host plants. Rubus cissoides (bush lawyer), Rubus ursinus ‘Mapua’ (Boysenberry), and Rubus fruticosus (blackberry) released varying HIPVs in response to raspberry bud moth larval feeding. Bush lawyer, the native host, gave a limited response restricted to green leaf volatiles (GLVs). The non-native hosts, blackberry and Boysenberry, gave strong HIPV responses releasing a number of unique nitrogenous compounds in conjunction with the GLVs. Dolichogenidea carposinae was found to parasitise raspberry bud moth on blackberry.