Location: Vegetable Research
Project Number: 6080-22000-030-004-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jun 1, 2020
End Date: May 31, 2025
Objective:
1. Identify new pheromone compounds from live unmated pestiferous click beetle females.
2. Develop new or improved methods for the management of insect pests (including whiteflies and soil dwelling pests) and whitefly-transmitted viruses in vegetable crop production systems. Sub-objective 3c - Characterize infochemicals and plant-based chemicals of vegetable pests (e.g., click beetles, sweetpotato weevil and whiteflies) for use in detection, monitoring, and biologically-based management. This agreement will complement the parent project by identifying insect-produced chemicals used for attraction by pests and that can be used for pest management.
2. Field screen possible pheromone compounds to determine which chemicals or blends are attractive to pestiferous click beetle species.
Approach:
Screening of putative pheromone chemicals will be performed in two general habitats: 1) native vegetation in potato growing areas where diverse and relatively dense assemblages of wireworm species can be found, and 2) agricultural habitats where pestiferous species of wireworms are prevalent, in multiple geographic and climatic regions. Synthetic chemicals tested using a randomized complete block experimental design. Pitfall traps will be baited with test lures (dispensed from rubber septa), and unbaited traps will be used as controls. A 1:1 mixture of water and propylene glycol will be used as a killing agent in the traps. Traps will be placed in the soil in crop fields or at field borders adjacent to non-crop habitat. Traps will be emptied of insects, lures and killing agent will be replaced, and damaged or missing traps replaced at weekly intervals from spring through the end of the summer growing season, which may vary with location. Trap catches will be identified to species and sex and compared between traps baited with a chemical compound and a paired unbaited control trap by repeated measures analysis.
To identify new pheromone compounds, live virgin females will be obtained by rearing field-collected larvae to adults in the laboratory, individually, in plexiglass containers. Additionally, click beetles will be collected by sweep netting and live trapping. Volatiles will be collected from live beetles for ~1 week. If the beetles do not produce sufficient quantities of pheromone, volatiles will be collected from macerated female abdomen tips. Extracts will be analyzed by gas chromatography(GC)-electroantennography to locate likely pheromone compounds, which will then be identified by a combination of GC-mass spectrometry, GC retention indices, microchemical tests, and as needed microbore nuclear magnetic resonance spectrometry.
