Location: Horticultural Crops Disease and Pest Management Research Unit
Project Number: 2072-22000-044-025-G
Project Type: Grant
Start Date: Sep 1, 2021
End Date: Oct 31, 2024
Objective:
1. Measure and characterize volatiles of a plant-based deterrent for spotted-winged drosophila.
2. Evaluate the physiological response of spotted-wing drosophila after exposure to the plant-based deterrent.
3. Evaluate the efficacy of a plant-based deterrent as part of an integrated program for the management of spotted-winged drosophila.
Approach:
Towards Objective 1, volatiles from the head space of a glass container will be drawn (ca. 0.5-1 liters/min) using a vacuum pump and collected into a PorapakTM Q for characterization. Adsorbent samplings will be conducted at 0, 1, 2, 4 and 5 days at room temperature from 1-3 kg of plant material that was sprayed with deterrent and compared with a negative control. The volatiles will be eluted using 1 ml of appropriate solvent, reduced to 200µL via solvent evaporation under low-velocity air stream. Volatile organic collections will be characterized by GC-MS. The headspace above the product will be sampled with a gas-tight syringe and directly injected into the GC-MS. The instrument’s library software will aid to match signals obtained.
For Objective 2, volatiles collected as part of Objective 1 will be used in a whole-insect behavioral bioassays. Ten adult 3-day old female and male SWD each will be trialed for antennal response. A SWD antenna, separated at the head and cut at the fifth segment, will be mounted on the tip of a 1.5 mm glass capillary, filled with Kaissling solution, and equipped with a pure gold/silver wire indifferent electrode. A pure silver wire recording electrode within the glass capillary tube filled with saline, will be maneuvered allowing for electrical contact with the SWD antennal tip. The output signal from the antennae will be amplified and filtered using a simple resistance/capacitance (RC) high-pass filter. The signal will be recorded and synchronized using a GC integrator. This signal will be amplified and recorded simultaneously with volatile release.
Finally, for Objective 3 the intensity of physiological response elicited by the insect antenna to determine SWD antennal response towards each individual emitted volatile will allow for the determination of optimal dose. These doses will inform creation of formulations allowing first for replicated and randomized whole-insect laboratory followed by controlled field trials in order to screen improved formulations.
