1a. Objectives (from AD-416):
1. Establish attraction behavior of coffee berry borer. 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 CBB 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 coffee. Due to the fact that the pest spends a significant part of its life cycle in the berry, it is unclear if conventional pheromones are important in the biology of this insect. However we suspect kairomones (plant derived volatile chemicals arising from the plant may serve as important behavior cues. 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) and even gustatory electrophysiology (taste recordings). 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. Repellents - repellents will be identified using many of the procedures lists about for attractants research. Since both repellents and attracts can give similar electrophysiological signals most of the discovery will be based on the “bioassay”, tests of the compound against the whole insect. 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)
3. Progress Report:
The goal of the Trust Agreement is improved semiochemicals for detection and control of coffee berry borer. The work being done 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. Field evaluations of identified coffee volatiles were tested with methanol/ethanol packets for attraction and improvement of trap captures to methanol/ethanol alone. Tests were designed with a control for each treatment trap and rotated daily to alleviate positional effects with population variation. Brocap traps were used in all compound evaluations. Twenty five identified compounds from headspace analysis of ripe coffee cherries were tested. Two identified coffee compounds combined with methanol/ethanol had significantly better trap captures compared to methanol/ ethanol alone. Methylene chloride extracts of red, green and dried coffee cherries were also tested in field evaluations. Red coffee extract showed the most significant trap captures compared to the control traps followed by green coffee extracts and dried coffee extracts were least significant. Three compounds identified from coffee extracts and one pheromone compound showed electrophysiological responses with coffee berry borer females. The pheromone compound was also behaviorally active in the field. Further evaluations on concentration effects are continuing.