Improved Semiochemicals for Detection of Coconut Rhinoceros Beetle, An Invasive Pest on Coconut and Other Tropical Plants
Tropical Crop and Commodity Protection Research
2012 Annual Report
1a.Objectives (from AD-416):
1. Establish attraction behavior of coconut rhinoceros beetle.
2. Identify behaviorally active compounds using GC-EAD and GC-MS.
3. Validate attraction using lab and field bioassay and develop formulations and traps.
1b.Approach (from AD-416):
Attraction studies - we proposed to develop information on potential attractants of CRB using proven techniques used against other pests. The first is a solid understanding of the pest behavior and ecology; especially as it related to host plants such as coconut. Due to the fact that the pest is currently not established in Hawaii, studies will have to be conducted in a suitable quarantine facility (HDOA or USDA-FS, Volcano) or be carried out where the best can be predicted (Guam). However we suspect kairomones (plant derived volatile chemicals arising from the plant) may serve as important synergist to the aggregation pheromone to elicit flight and/or arrestment behaviors. Identification of these chemicals will be carried out using gas chromatography-mass spectrometry (GC-MS). In order to determine if the chemicals are detected by the insect we will employ coupled gas chromatography-electroantennogram detection (GC-EAD). Putative identified chemicals will be tested behaviorally in behavior arena such as olfactometers and a behavioral “servosphere” which allows us to measure precise distances and angles of insect that walk towards or from chemicals.
Field testing - Once putative semiochemicals are found we plan to test these in the field to establish their efficacy under real-world situations. Formulations and/or dispensers for these new semiochemicals will be developed and tested in collaboration with private industry partners who can manufacture the semiochemicals and traps for purchase by the public. (Technology transfer)
The goal of this Trust Agreement is improved semiochemicals for detection of coconut rhinoceros beetle. The research being conducted contributes directly to Objective 2 of the parent project to identify attractants from host and non-host plants and determine physiological and environmental factors affecting or modulating pest behavior.
Studies on the biology of the coconut rhinoceros beetle (CRB) were undertaken during two visits to Guam, USA, where the pest is established. Working with cooperators, we learned that the biology and behavior of this pest is complex with adults and larvae occupying different habitats. During the second trip, we shipped our electrophysiology equipment and conducted some preliminary electroantennogram (EAG) studies on this insect. Good electrophysiological responses were collected from some beetles to beetle pheromone and some unknown plant volatiles. We also initiated trapping of plant and insect produced volatiles and developed laboratory and field bioassays for further testing of this insect. Volatiles will be analyzed for the next phase of this project.