Location: Insect Control and Cotton Disease Research
Project Number: 3091-22000-038-070-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Aug 1, 2020
End Date: Jul 31, 2025
Objective:
1) Identify the pheromone components of the pecan weevil
2) Determine the ratio of the pheromone components
Approach:
Tedders and Circle traps will be established in two or three weevil-infested pecan orchards in Comanche County, TX, to collect adult pecan weevils soon after emergence from the soil but before adult weevils begin to feed on immature pecans. Traps will be established in early August and monitored every two to three days until weevils are detected at which time traps will be checked daily for one to two weeks or until enough male weevils are collected (minimum of 12 male adults). Each male weevil will be held separately in a 1-pint carton and provided a fresh immature pecan (gel/dough stage) daily for six days to promote pheromone production. Following the 6-day feeding period, weevils will be placed individually in pheromone collection vessels with a fresh pecan. Another set of four collection vessels will contain only pecans to allow differentiation of pecan and weevil emissions. Headspace volatiles will be collected over a 24-hour period on glass columns containing a bed of Super Q resin. The resin in each collection column will be eluted with methylene chloride, and the first 1 ml of eluate from each column will be captured in 1.5-ml GC vials. Samples will be analyzed on a Shimadzu gas chromatography/mass spectrometry system equipped with a DB-5M column operated in EI mode. Spectral data will subjected to the Wiley Registry of Mass Spectral Data 10th Edition and the 2011 NIST/EPA/NIH Mass Spectral Libraries to assist in identification of volatiles.
