Predicting When, Why and Where Asian citrus psylllids move to increase effectiveness of insecticide sprays

Predicting When, Why and Where Asian citrus psylllids move to increase effectiveness of insecticide sprays

Report Date: 03/15/2016
Project: 15-024   Year: 2016
Category: ACP Vector
Author: Lukasz Stelinski
Sponsor: Citrus Research and Development Foundation

We built a new wind tunnel adapted for Asian citrus psyllid; this wind tunnel has been controlled for regular air flow and absence of air disturbance. We tested the effect of wind direction on psyllid ability to find a young emerging leaves (�flush�) introduced in the wind tunnel. In the absence of wind, or when they have to move in the same direction than the wind (downwind) psyllids found the introduced flush at a 30% rate. On the contrary, when psyllids had to move against the wind (upwind) only 11% settled on the flush. This may indicate that psyllids are reluctant to move upwind. Also the damaged flush in the wind tunnel may not release enough volatiles to attract psyllids. We will pursue our work with the wind tunnel with higher dosage of volatiles and different wind speeds to better understand psyllid movement depending of wind direction. Additionally, we developed a pressure chamber to measure psyllid dispersion depending of controlled pressure changes. Our pressure chamber consists of a glass chamber with controlled air flows. Psyllid are placed in the box within the chamber, and the pressure of the chamber is manipulated by changing the flow of air pushed in the chamber. When the pressure stabilized the box is open with a remote system and the number of psyllid captured by a small band of yellow sticky trap hanged on the top of the pressure chamber are counted. With this system, we were able to study the effect of barometric pressure changes on psyllid dispersal abilities. We found that psyllids responded to barometric changes rather than to different stable pressure. Psyllids were not more active at 1009 mbar or at 1022 mbar. However, we found that psyllids tend to disperse more as barometric pressure increased, and were less mobile when barometric chamber dropped. For instance, with an increase of 2.4 mbar per hour we captured 7.2 psyllid per hour, whereas with a decrease of -2.4 mbar per hour we only captured 4 psyllids per hour.


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